Page 1 This manual applies to SN 6560XXX and higher. HYDRA 2620A Data Acquisition Unit 2625A Data Logger 2635A Data Bucket Service Manual PN 202231 February 1997 © 1997 Fluke Corporation, All rights reserved. Printed in U.S.A. All product names are trademarks of their respective companies.
Page 2 Fluke’s warranty obligation is limited, at Fluke’s option, to refund of the purchase price, free of charge repair, or replacement of a defective product which is returned to a Fluke authorized service center within the warranty period.
Page 3 20402. Stock No. 004-000-00345-4. Declaration of the Manufacturer or Importer We hereby certify that the Fluke Models 2625A Data Logger, 2620A Data Acquisition Unit and 2635A Data Bucket are in compliance with BMPT Vfg 243/1991 and is RFI suppressed. The normal operation of some equipment (e.g.
Page 5 Safety Summary Safety Terms in this Manual This instrument has been designed and tested in accordance with IEC Publication 1010, Safety Requirements for Electronical Measuring, Control and Laboratory Equipment. This Service Manual contains information, warnings, and cautions that must be followed to ensure safe operation and to maintain the instrument in a safe condition.
Page 6 Use the Proper Fuse To avoid fire hazard, use only a fuse identical in type, voltage rating, and current rating as specified on the rear panel fuse rating label. Grounding the Standard The instrument utilized controlled overvoltage techniques that require the instrument to be grounded whenever normal mode or common mode ac voltage or transient voltages may occur.
Page 7: Table Of Contents
Table of Contents Chapter Title Page Introduction and Specifications............1-1 1-1. Introduction ..................1-3 1-2. Options and Accessories ..............1-3 1-3. Operating Instructions ................. 1-3 1-4. Organization of the Service Manual ........... 1-4 1-5. Conventions ..................1-5 1-6. Specifications ..................1-7 Theory of Operation (2620A/2625A)..........
Page 8 HYDRA Service Manual 2-32. Digital Kernel ................2-10 2-43. Digital I/O ................... 2-14 2-44. Digital Input Threshold .............. 2-15 2-45. Digital Input Buffers ..............2-15 2-46. Digital and Alarm Output Drivers ..........2-15 2-47. Totalizer Input ................2-16 2-48. External Trigger Input Circuits ..........2-16 2-49.
Page 9 Contents (continued) 2A-22. Main PCA ..................2A-7 2A-23. Power Supply Circuit Description..........2A-8 2A-31. Digital Kernel ................2A-10 2A-42. Digital I/O..................2A-18 2A-43. Digital Input Threshold ............... 2A-19 2A-44. Digital Input Buffers..............2A-19 2A-45. Digital and Alarm Output Drivers ..........2A-19 2A-46.
Page 10 HYDRA Service Manual 3-22. Install Miscellaneous Chassis Components ........3-13 3-23. Install the A/D Converter PCA ............3-13 3-24. Install the Main PCA ..............3-14 3-25. Install the IEEE-488 Option (2620A Only) ........3-14 3-26. Install the Memory PCA (2625A Only) .......... 3-14 3-27.
Page 11 Contents (continued) 5-7. Power Fail Detection ............... 5-8 5-8. 5-Volt Switching Supply..............5-8 5-9. Inverter .................... 5-9 5-10. Analog Troubleshooting ..............5-12 5-11. DC Volts Troubleshooting .............. 5-17 5-12. AC Volts Troubleshooting .............. 5-17 5-13. Ohms Troubleshooting ..............5-18 5-14. Digital Kernel Troubleshooting ............
Page 12 HYDRA Service Manual 5A-30. Failure to Illuminate the Battery Led .......... 5A-31 5A-31. Failure to Write to Memory Card..........5A-32 5A-32. Write/Read Memory Card Test (Destructive) ......5A-32 List of Replaceable Parts ..............6-1 6-1. Introduction ..................6-3 6-2. How to Obtain Parts ................6-3 6-3.
Page 13 List of Tables Table Title Page 1-1. Hydra Features......................1-6 1-2. Accessories ......................1-7 1-3. 2620A/2625A Specifications................. 1-8 1-4. 2635A Specifications..................... 1-20 2-1. Microprocessor Memory Map ................2-11 2-2. Option Type Sensing ..................... 2-14 2-3. Programmable Input Threshold Levels ..............2-15 2-4.
Page 14 HYDRA Service Manual 5-3. Power Supply Troubleshooting Guide..............5-13 5-4. DC Volts HI Troubleshooting ................5-17 5-5. AC Volts HI Troubleshooting ................5-18 5-6. Ohms Open-Circuit Voltage .................. 5-18 5-7. Ohms HI Troubleshooting ..................5-18 5-8. Display Initialization ..................... 5-23 5-9.
Page 15 List of Figures Figure Title Page 2-1. Interconnect Diagram .................... 2-4 2-2. Overall Functional Block Diagram................ 2-5 2-3. Analog Simplified Schematic Diagram..............2-18 2-5. Ohms Simplified Schematic .................. 2-23 2-6. AC Buffer Simplified Schematic................2-24 2-7. A/D Converter Simplified Schematic..............2-26 2-8.
Page 16 HYDRA Service Manual 5-6. Integrator Output ....................5-17 5-7. Microprocessor Timing ..................5-20 5-8. Test Points, Display PCA (A2)................5-22 5-9. Display Controller to Microprocessor Signals ............5-23 5-10. Display Test Pattern #1..................5-24 5-11. Display Test Pattern #2..................5-24 5A-1.
Page 17 Chapter 1 Introduction and Specifications Title Page 1-1. Introduction ..................1-3 1-2. Options and Accessories ..............1-3 1-3. Operating Instructions ................1-3 1-4. Organization of the Service Manual............. 1-4 1-5. Conventions..................1-5 1-6. Specifications ..................1-7...
Page 18 HYDRA Service Manual...
Page 19: Introduction And Specifications
• Accessory 2620A-100 (Connector Kit). The instrument can be mounted in a standard 19-inch rack panel on either the right-hand or left-hand side using the Fluke M00-200-634 Rackmount Kit. Accessories are listed in Table 1-2. 1-3. Operating Instructions Full operating instructions are provided in the Hydra User Manual (2620A or 2625A) and in the Hydra Data Bucket User Manual (2635A).
Page 20: Organization Of The Service Manual
HYDRA Service Manual 1-4. Organization of the Service Manual This manual focuses on performance tests, calibration procedures, and component-level repair of each of the instruments. To that end, manual sections are often interdependent; effective troubleshooting may require not only reference to the troubleshooting procedures in Section 5, but also some understanding of the detailed Theory of Operation in Section 2 and some tracing of circuit operation in the Schematic Diagrams presented in Section 8.
Page 21: Conventions
Introduction and Specifications Conventions Chapter 7. IEEE-488 Option (2620A only) This chapter describes the IEEE-488 option. Included are specifications, theory of operation, maintenance, and a list of replaceable parts. Schematic diagrams for this option are included at the end of the overall Service Manual (Chapter 8). Chapter 8.
Page 22 HYDRA Service Manual Table 1-1. Hydra Features • Channel Scanning Can be continuous scanning, scanning at an interval time, single scans, or triggered (internal or external) scans. • Channel Monitoring Make measurements on a single channel and view these measurements on the display. •...
Page 23: Specifications
Shielded RS-232 modem cable. Connects the instrument to a modem with properly configured DB-25 male pin connector. Use an RS40 and an RS41 cable in series to connect with an IBM PC/AT(R). RS42 Shielded serial printer cable. Contact Fluke for list of compatible printers. TL20 Industrial test lead set. TL70A Test lead set (one set is supplied with the instrument).
Page 24 HYDRA Service Manual Table 1-3. 2620A/2625A Specifications The instrument specifications presented here are applicable within the conditions listed in the Environmental portion of this specification. The specifications state total instrument accuracy following calibration, including: • A/D errors • Linearization conformity •...
Page 25 Introduction and Specifications Specifications Table 1-3. 2620A/2625A Specifications (cont) Thermocouple Inputs Accuracy (±°C)* Thermocouple 18°C to 28°C 0°C to 60°C Temperature 90 Days 1 Year 1 Year 1 Year 1 Year Type (°C) Slow Slow Fast Slow Fast -100.00 0.49 0.53 1.00 0.73...
Page 26 HYDRA Service Manual Table 1-3. 2620A/2625A Specifications (cont) Thermocouple Inputs (cont) Input Impedance 100 MΩ minimum in parallel with 150 pF maximum Common Mode and Normal Mode Rejection See Specifications, DC Voltage Inputs Crosstalk Rejection Refer to "Crosstalk Rejection" at the end of this table. Open Thermocouple Detect Small ac signal injection and detection scheme before each measurement detects greater than 1 to 4 kΩ...
Page 27 Introduction and Specifications Specifications Table 1-3. 2620A/2625A Specifications (cont) AC Voltage Inputs (True RMS AC Voltage, AC-Coupled Inputs) Resolution Range Minimum Input for Rated Accuracy Slow Fast 10 µV 100 µV 300 mV 20 mV 100 µV 1 mV 200 mV 1 mV 10 mV 300V...
Page 28 HYDRA Service Manual Table 1-3. 2620A/2625A Specifications (cont) AC Voltage Inputs (True RMS AC Voltage, AC-Coupled Inputs) (cont) Maximum Frequency Input at Upper Frequency 20 Hz - 50 Hz 300V rms 50 Hz - 100 Hz 300V rms 100 Hz - 10 kHz 200V rms 10 kHz - 20 kHz 100V rms...
Page 29 Introduction and Specifications Specifications Table 1-3. 2620A/2625A Specifications (cont) Ohms Input Resolution Range Typical Full Maximum Current Maximum Open Scale Voltage Through Unknown Circuit Voltage Slow Fast 300Ω 10 mΩ 0.1Ω 0.22V 1 mA 3.2V 110 µA 3 kΩ 0.1Ω 1Ω...
Page 30 HYDRA Service Manual Table 1-3. 2620A/2625A Specifications (cont) Frequency Inputs (cont) Sensitivity Frequency Level (sine Wave) 15 Hz - 100 kHz 100 mV rms 100 kHz - 300 kHz 150 mV rms 300 kHz - 1 MHz 2V rms Above 1 MHz NotSpecified Maximum AC Input 300V rms or 424V peak on channels 0, 1, and 11...
Page 31 Introduction and Specifications Specifications Table 1-3. 2620A/2625A Specifications (cont) Maximum Autoranging Time (Seconds per Channel) Function Range Change Slow Fast 300 mV to 150V 0.25 0.19 150V to 300 mV 0.25 0.18 300 mV to 150V 1.40 1.10 150V to 300 mV 1.40 1.10 Ohms...
Page 32 HYDRA Service Manual Table 1-3. 2620A/2625A Specifications (cont) Digital and Alarm Outputs Output Logic Levels Logical "zero": 0.8V max for an Iout of -1.0 mA (1 LSTTL load) Logical "one": 3.8V min for an Iout of 0.05 mA (1 LSTTL load) For non-TTL loads: Logical "zero": 1.8V max for an Iout of -20 mA...
Page 33 Introduction and Specifications Specifications Table 1-3. 2620A/2625A Specifications (cont) Memory Life 10 years minimum over Operating Temperature range Stores: real-time clock, set-up configuration, and measurement data Common Mode Voltage 300V dc or ac rms maximum from any analog input(channel) to earth provided that channel to channel maximum voltage ratings are observed.
Page 34 HYDRA Service Manual Table 1-3. 2620A/2625A Specifications (cont) 2620A Options IEEE-488 (Option -05K) Capability codes:SH1, AH1, T5, L4, SR1, RL1, PP0, DC1, DT1, E1, TE0, LE0 and C0 Complies with IEEE-488.1 standard Crosstalk Rejection AC signals can have effects on other channels(crosstalk). These effects are discussed here by measurement function.
Page 35 Introduction and Specifications Specifications Table 1-3. 2620A/2625A Specifications (cont) AC Signal Crosstalk into an Ohms Channel AC Frequency = 50, 60 Hz, ±0.1%   Ohmss error OHMS Error Ratio =     VAC rms crosstalk Range Ratio (worst case) Ratio (typical) ...
Page 36 HYDRA Service Manual Table 1-4. 2635A Specifications The instrument specifications presented here are applicable within the conditions listed in the Environmental portion of this specification. The specifications state total instrument accuracy following calibration, including: • A/D errors • Linearization conformity •...
Page 37 Introduction and Specifications Specifications Table 1-4. 2635A Specifications (cont) Input Impedance 100 MΩ minimum in parallel with 150 pF maximum for all ranges 3V and below 10 MΩ in parallel with 100 pF maximum for the 30V and 300V ranges. Normal Mode Rejection 53 dB minimum at 60 Hz ±0.1%, slow rate 47 dB minimum at 50 Hz ±0.1%, slow rate...
Page 38 HYDRA Service Manual Table 1-4. 2635A Specifications (cont) Thermocouple Inputs Temperature Measurements - Accuracy (Thermocouples) (IPTS-68) Accuracy (±°C)* Thermocouple 18°C to 28°C 0°C to 60°C Temperature 90 Days 1 Year 1 Year 1 Year 1 Year Type (°C) Slow Slow Fast Slow Fast...
Page 39 Introduction and Specifications Specifications Table 1-4. 2635A Specifications (cont) Thermocouple Inputs Temperature Measurements - Accuracy (Thermocouples) (ITS-90) Accuracy (±°C)* Thermocouple 18°C to 28°C 0°C to 60°C Temperature 90 Days 1 Year 1 Year 1 Year 1 Year Type (°C) Slow Slow Fast Slow...
Page 40 HYDRA Service Manual Table 1-4. 2635A Specifications (cont) Thermocouple Inputs (cont) Input Impedance 100 MΩ minimum in parallel with 150 pF maximum Common Mode and Normal Mode Rejection See Specifications, DC Voltage Inputs Crosstalk Rejection Refer to "Crosstalk Rejection" at the end of Table 1-3. Open Thermocouple Detect Small ac signal injection and detection scheme before each measurement detects greater than 1 to 4 kΩ...
Page 41 Introduction and Specifications Specifications Table 1-4. 2635A Specifications (cont) AC Voltage Inputs (True RMS AC Voltage, AC-Coupled Inputs) Resolution Range Minimum Input for Rated Accuracy Slow Fast 10 µV 100 µV 300 mV 20 mV 100 µV 1 mV 200 mV 1 mV 10 mV 150/300V...
Page 42 HYDRA Service Manual Table 1-4. 2635A Specifications (cont) AC Voltage Inputs (True RMS AC Voltage, AC-Coupled Inputs) (cont) Maximum Frequency Input at Upper Frequency 20 Hz - 50 Hz 300V rms 50 Hz - 100 Hz 300V rms 100 Hz - 10 kHz 200V rms 10 kHz - 20 kHz 100V rms...
Page 43 Introduction and Specifications Specifications Table 1-4. 2635A Specifications (cont) Ohms Input Resolution Range Typical Full Maximum Current Maximum Open Scale Voltage Through Unknown Circuit Voltage Slow Fast 300Ω 10 mΩ 0.1Ω 0.22V 1 mA 3.2V 110 µA 3 kΩ 0.1Ω 1Ω...
Page 44 HYDRA Service Manual Table 1-4. 2635A Specifications (cont) Frequency Inputs (cont) Sensitivity Frequency Level (sine Wave) 15 Hz - 100 kHz 100 mV rms 100 kHz - 300 kHz 150 mV rms 300 kHz - 1 MHz 2V rms Above 1 MHz NotSpecified Maximum AC Input 300V rms or 424V peak on channels 0, 1, and 11...
Page 45 Introduction and Specifications Specifications Table 1-4. 2635A Specifications (cont) Maximum Autoranging Time (Seconds per Channel) Function Range Change Slow Fast 300 mV to 150V 0.25 0.19 150V to 300 mV 0.25 0.18 300 mV to 150V 1.40 1.10 150V to 300 mV 1.40 1.10 Ohms...
Page 46 HYDRA Service Manual Table 1-4. 2635A Specifications (cont) Digital and Alarm Outputs Output Logic Levels Logical "zero": 0.8V max for an Iout of -1.0 mA (1 LSTTL load) Logical "one": 3.8V min for an Iout of 0.05 mA (1 LSTTL load) For non-TTL loads: Logical "zero": 1.8V max for an Iout of -20 mA...
Page 47 Introduction and Specifications Specifications Table 1-4. 2635A Specifications (cont) General Channel Capacity 21 Analog Inputs 4 Alarm Outputs 8 Digital I/O (Inputs/Outputs) Measurement Speed Slow rate: 4 readings/second nominal Fast rate: 17 readings/second nominal 1.5 readings/second nominal for ACV and high-Ω inputs For additional information, refer to Typical Scanning Rate and Maximum Autoranging Time.
Page 48 HYDRA Service Manual 1-32...
Page 49: Theory Of Operation (2620A/2625A)
Chapter 2 Theory of Operation (2620A/2625A) Title Page 2-1. Introduction ..................2-3 2-2. Functional Block Description............... 2-3 2-3. Main PCA Circuitry................. 2-3 2-4. Power Supply................2-3 2-5. Digital Kernel ................2-3 2-6. Serial Communication (Guard Crossing) ........2-6 2-7. Digital Inputs and Outputs............2-6 2-8.
Page 50 HYDRA Service Manual 2-47. Totalizer Input ................2-16 2-48. External Trigger Input Circuits............ 2-16 2-49. A/D Converter PCA ................. 2-16 2-50. Analog Measurement Processor ..........2-16 2-51. Input Protection ................2-17 2-52. Input Signal Conditioning............2-20 2-58. Passive and Active Filters............2-25 2-59.
Page 51: Introduction
Theory of Operation (2620A/2625A) Introduction 2-1. Introduction The theory of operation begins with a general overview of the instrument and progresses to a detailed description of the circuits of each pca. The instrument is first described in general terms with a Functional Block Description. Then, each block is detailed further (often to the component level) with Detailed Circuit Descriptions.
Page 52 HYDRA Service Manual DIGITAL I/O AND TOTALIZE INPUT ALARM OUTPUTS SCAN TRIGGER INPUT AC IN RS-232 DISPLAY MAIN 2625A MEMORY ONLY REAR 2620A IEEE PANEL ONLY CHANNEL 0 CHANNELS 11…20 ANALOG INPUT CONVERTER CONNECTOR CHANNELS 1…10 S1F.EPS Figure 2-1. Interconnect Diagram...
Page 53: Overall Functional Block Diagram
Theory of Operation (2620A/2625A) Functional Block Description ANALOG INPUT CONNECTOR INPUT MULTIPLEXING INPUT PROTECTION INPUT SIGNAL CONDITIONING ANALOG MEASUREMENT PROCESSOR (A/D CONVERTER) MICRO CONTROLLER A/D CONVERTER SERIAL INGUARD GUARD CROSSING OUTGUARD COMMUNICATION DIGITAL VACUUM FLUORESCENT DISPLAY RS-232 µ P DISPLAY CONTROLLER IEEE-488 CALENDAR FRONT PANEL...
Page 54: Serial Communication (Guard Crossing)
HYDRA Service Manual 2-6. Serial Communication (Guard Crossing) This functional block provides a high isolation voltage communication path between the Digital Kernel of the Main PCA and the microcontroller on the A/D Converter PCA. This bidirectional communication circuit requires power supply voltages from the Power Supply block.
Page 55: Channel Selection Circuitry
Theory of Operation (2620A/2625A) Detailed Circuit Description 2-14. Channel Selection Circuitry This circuitry consists of a set of relays and relay-control drivers. The relays form a tree that routes the input channels to the measurement circuitry. Two of the relays are also used to switch between 2-wire and 4-wire operation.
Page 56: Power Supply Circuit Description
HYDRA Service Manual 2-24. Power Supply Circuit Description The Hydra power supply consists of three major sections: • Raw DC Supply The raw dc supply converts line voltage (90V to 264V ac) to a dcoutput of 7.5V to 35V. • 5V Switcher Supply The 5V switching supply regulates the 7.5 to 35V dc input to anominal 5.1V ±0.25V dc (VCC).
Page 57 Theory of Operation (2620A/2625A) Detailed Circuit Description Dual inductor A1T2 regulates the current that flows from the raw supply to the load as the switching transistor in A1U9 is turned on and off. Complementary switch A1CR10 conducts when the switching transistor is off. The pulse-width modulator comparator in A1U9 compares the output to the reference and sets the ON-time/OFF-time ratio to regulate the output to 5.1V dc.
Page 58: Digital Kernel
HYDRA Service Manual amplifier. A1VR2 is the reference for the positive supply. A1R14 provides the current to bias the reference zener. A1C4 is the output filter, and A1C9 provides frequency compensation of the regulator circuit. Transistor A1Q1 and resistor A1R13 make up the current-limit circuit.
Page 59 Theory of Operation (2620A/2625A) Detailed Circuit Description The Microprocessor communicates to the Microcontroller on the A/D Converter PCA (via the Serial Communication circuit) using an asynchronous communication protocol at 4800 baud. Communication to the Microcontroller (A3U9) originates at A1U4-11. Communication from the A/D’s Microcontroller to the Microprocessor appears at A1U4- 10.
Page 60 HYDRA Service Manual phototransistor base discharges through A1R16. With this arrangement, the rise and fall times of the phototransistor collector signal are nearly symmetrical. The transmission of data from the Microcontroller (A3U9) to the Microprocessor (A1U4) is accomplished via the circuit made up of A3Q1, A3R7, A1U5, A1R7, and A1R3.
Page 61 Theory of Operation (2620A/2625A) Detailed Circuit Description 2-39. EEPROM The EEPROM contains 64 registers, each of which is 16 bits long. These registers are used to provide nonvolatile storage of some of the instrument configuration information and all of the calibration information. When the Microprocessor is communicating to the EEPROM, Chip Select input (A1U1-1) is driven high to enable the EEPROM interface.
Page 62: Digital I/O
HYDRA Service Manual Data Terminal Ready (DTR) is a modem control signal controlled by the Microprocessor. When the instrument is powered up, the Microprocessor port pin (A1U4-32) goes high, which results in the RS-232 driver output (A1U25-7) going to - 5.0V dc.
Page 63: Digital Input Threshold
Theory of Operation (2620A/2625A) Detailed Circuit Description 2-44. Digital Input Threshold 2-1. The Digital Input Threshold circuit sets the input threshold level for the Digital Input Buffers and the Totalizer Input. A software programmable voltage divider (A1U17, A1R35, A1R36, A1R37) and a unity gain buffer amplifier (A1AR1) are the main components in this circuit.
Page 64: Totalizer Input
HYDRA Service Manual 2-47. Totalizer Input The Totalizer Input circuit consists of Input Protection, a Digital Input Buffer circuit, and a Totalizer Debouncer circuit. The Digital Input Buffer for the totalizer is protected from electrostatic discharge (ESD) damage by A1R49 and A1C43. Refer to the detailed description of the Digital Input Buffer circuit for more information.
Page 65: Input Protection
Theory of Operation (2620A/2625A) Detailed Circuit Description The Analog Measurement Processor (A3U8) is a 68-pin CMOS device that, under control of the A/D Microcontroller (A3U9), performs the following functions: • Input signal routing • Input signal conditioning • Range switching •...
Page 66: Analog Simplified Schematic Diagram
HYDRA Service Manual s3f.eps Figure 2-3. Analog Simplified Schematic Diagram 2-18...
Page 67 Theory of Operation (2620A/2625A) Detailed Circuit Description Table 2-4. Analog Measurement Processor Pin Descriptions Name Description +5.4V supply ACBO AC buffer output (not used) AGND2 Analog ground ACR4 AC buffer range 4 (300V) ACR3 AC buffer range 3 (30V) ACR2 AC buffer range 2 (3V) ACR1 AC buffer range 1 (300 mV)
Page 68: Input Signal Conditioning
HYDRA Service Manual Table 2-4. Analog Measurement Processor Pin Descriptions (cont) Name Description Integrator summing node Buffer output, 100 mV range B.32 Buffer output, 300 mV range Buffer output, 1000 mV range B3.2 Buffer output, 3V range VREF+ A/D voltage reference plus VREF- A/D voltage reference minus A/D reference amplifier output...
Page 69 Theory of Operation (2620A/2625A) Detailed Circuit Description Table 2-5. Function Relay States Relay Position Function A3K17 A3K16 A3K15 DC mV, 3V,Thermocouples Reset DC 30V, 300V Reset Ohms, RTDs Reset Reset Frequency Reset 2-54. DC Volts and Thermocouples For the 3V and lower ranges (including thermocouples), the HI input signal is applied directly to the A3U8 analog processor through A3R11, A3K17, and A3R42.
Page 70 HYDRA Service Manual A3R11 A3K17 INPUT HI A3R10 A3Z4 PASSIVE HIGH FILTER A3Z4 10.01k A3R34 A3K16 INPUT LO s4f.eps Figure 2-4. DC Volts 300V Range Simplified Schematic When an input is switched in for a measurement, the ohms source in Analog Processor A3U8 is set to the correct voltage for the range selected and is connected to the appropriate reference resistor in network A3Z4.
Page 71: Ohms Simplified Schematic
Theory of Operation (2620A/2625A) Detailed Circuit Description OHMS VOLTAGE SOURCE A3Z4 INTEGRATE REFERENCE REFERENCE – RESISTOR A3R34 HIGH A3K16 A3RT1 & A3R10 A3R11 A3R42 PASSIVE HIGH A3K17 FILTER UNKNOWN INTEGRATE RESISTOR UNKNOWN •R •R s5f.eps Figure 2-5. Ohms Simplified Schematic The reference resistor for the 300-kΩ, 3-MΩ, and 10-MΩ...
Page 72: Ac Buffer Simplified Schematic
HYDRA Service Manual Since virtually no current flows through the sense path, no error voltages are developed that would add to the voltage across the unknown resistance; this 4-wire measurement technique eliminates user lead-wire and instrument relay contact and circuit board trace resistance errors.
Page 73: Passive And Active Filters
Theory of Operation (2620A/2625A) Detailed Circuit Description Table 2-6. AC Volts Input Signal Dividers Range Drive Signal A3Z3 Divider Overall Gain Resistor(s) 300 mV ACR1 111.1 kΩ ACR2 12.25 kΩ || 111.1 kΩ 0.25 ACR3 1.013 kΩ || 111.1 kΩ 0.025 150/300V ACR4...
Page 74: A/D Converter
HYDRA Service Manual 2-59. A/D Converter Figure 2-7 shows the dual slope a/d converter used in the instrument. The unknown input voltage is buffered and used to charge (integrate) a capacitor for an exact period of time. This integrator capacitor is then discharged by the buffered output of a stable and accurate reference voltage of opposite polarity.
Page 75: Inguard Microcontroller Circuitry
Theory of Operation (2620A/2625A) Detailed Circuit Description The current through the selected integrator input resistor charges integrator capacitor A3C13, with the current dependent on the buffer output voltage. After the integrate phase, the buffer is connected to the opposite polarity reference voltage, and the integrator integrates back toward zero capacitor voltage until the comparator trips.
Page 76: Open Thermocouple Check
HYDRA Service Manual The coils for the relays are driven by the outputs of Darlington drivers A3U4, A3U5, A3U10, A3U11, and A3U12. The relays are switched when a 6-millisecond pulse is applied to the appropriate reset or set coil by the NPN Darlington drivers in these ICs. When the port pin of Microcontroller A3U9 connected to the input of a driver is set high, the output of the driver pulls one end of a relay set or reset coil low.
Page 77: Display Pca
Theory of Operation (2620A/2625A) Detailed Circuit Description 2-64. Display PCA Display Assembly operation is classified into six functional circuit blocks: the Main PCA Connector, the Front Panel Switches, the Display, the Beeper Drive Circuit, the Watchdog Timer/Reset Circuit, and the Display Controller. These blocks are described in the following paragraphs.
Page 78: Display
HYDRA Service Manual approximately 20 kΩ. Checking resistances between any two signals (SWR1 through SWR6) verifies proper termination by resistor network A2Z1. 2-67. Display The custom vacuum-fluorescent display (A2DS1) comprises a filament, 11 grids (numbered 0 through 10 from right to left on the display), and up to 14 anodes under each grid.
Page 79: Display Controller
Theory of Operation (2620A/2625A) Detailed Circuit Description 4.75-second watchdog timeout period. Each time a low-to-high transition of DISTX is detected on A2U5-2, capacitor A2C2 is discharged to restart the timeout period. If there are no low-to-high transitions on DISTX during the 4.75-second period, A2U5-13 transitions from high to low, triggers the other half of A2U5, and causes output A2U5-12 to go low.
Page 80: Grid Control Signal Timing
HYDRA Service Manual Table 2-8. Display Initialization Modes A2TP4 A2TP5 Power-Up Display Initialization All Segments OFF All Segments ON (default) Display Test Pattern #1 Display Test Pattern #2 The Display Controller provides 11 grid control outputs and 15 anode control outputs (only 14 anode control outputs are used).
Page 81: Memory Pca (2625A Only)
Theory of Operation (2620A/2625A) Detailed Circuit Description GRID/ANODE TIMING 1 . 1 4 m s GRID(X) -30V 116 µs ANODE(14..0) -30V 19 µs 56 µs 60 µs 98 µs GRID(X-1) -30V s10f.eps Figure 2-10. Grid-Anode Timing Relationships 2-71. Memory PCA (2625A Only) The Memory PCA is a serially-accessed, byte-wide, nonvolatile 256K-byte memory that is capable of storing up to 2047 scans of data.
Page 82: Byte Counter
HYDRA Service Manual the WE* signal is low, NAND gate output A6U2-3 goes high to latch the data bus into the lower part of the page register (A6U1).When register select PAGEH goes high and the WE* signal is low, NAND gate output A6U2-8 goes high to latch the lower three bits of the data bus into the high part of the page register (A6U4).
Page 83: Theory Of Operation (2635A)
Chapter 2A Theory of Operation (2635A) Title Page 2A-1. Introduction ..................2A-3 2A-2. Functional Block Description...............2A-3 2A-3. Main PCA Circuitry.................2A-3 2A-4. Power Supply................2A-3 2A-5. Digital Kernel ................2A-3 2A-6. Serial Communication (Guard Crossing) ........2A-6 2A-7. Digital Inputs and Outputs............2A-6 2A-8. A/D Converter PCA .................2A-6 2A-9.
Page 84 HYDRA Service Manual 2A-46. Totalizer Input ................2A-19 2A-47. External Trigger Input Circuits............2A-20 2A-48. A/D Converter PCA .................2A-20 2A-49. Analog Measurement Processor ..........2A-20 2A-50. Input Protection ................2A-24 2A-51. Input Signal Conditioning............2A-25 2A-57. Passive and Active Filters............2A-30 2A-58. A/D Converter ................2A-30 2A-59. Inguard Microcontroller Circuitry ..........2A-32 2A-60.
Page 85: 1. Introduction
Theory of Operation (2635A) Introduction 2A-1. Introduction The theory of operation begins with a general overview of the instrument and progresses to a detailed description of the circuits of each pca. The instrument is first described in general terms with a Functional Block Description. Then, each block is detailed further (often to the component level) with Detailed Circuit Descriptions.
Page 86 HYDRA Service Manual DIGITAL I/O AND TOTALIZE INPUT ALARM OUTPUTS SCAN TRIGGER INPUT AC IN RS-232 DISPLAY MAIN MEMORY CRAD INTERFACE CHANNEL 0 CHANNELS 11…20 ANALOG INPUT CONVERTER CONNECTOR CHANNELS 1…10 S11F.EPS FIGURE 2A-1. InterconnectDiagram (2635A) 2A-4...
Page 87 Theory of Operation (2635A) Functional Block Description ANALOG INPUT CONNECTOR INPUT MULTIPLEXING INPUT PROTECTION INPUT SIGNAL CONDITIONING ANALOG MEASUREMENT PROCESSOR (A/D CONVERTER) MICRO CONTROLLER A/D CONVERTER INGUARD SERIAL GUARD COMMUNICATION OUTGUARD CROSSING RS-232 µ P NVRAM & FLASH MEMORY REAL-TIME MEMORY CARD CLOCK...
Page 88: 6. Serial Communication (Guard Crossing)
HYDRA Service Manual 2A-6. Serial Communication (Guard Crossing) This functional block provides a high isolation voltage communication path between the Digital Kernel of the Main PCA and the microcontroller on the A/D Converter PCA. This bidirectional communication circuit requires power supply voltages from the Power Supply block.
Page 89: 14. Channel Selection Circuitry
Theory of Operation (2635A) Detailed Circuit Description 2A-14. Channel Selection Circuitry This circuitry consists of a set of relays and relay-control drivers. The relays form a tree that routes the input channels to the measurement circuitry. Two of the relays are also used to switch between 2-wire and 4-wire operation.
Page 90: 23. Power Supply Circuit Description
HYDRA Service Manual 2A-23. Power Supply Circuit Description The Hydra power supply consists of three major sections: • Raw DC Supply The raw dc supply converts line voltage (90V to 264V ac) to a dcoutput of 7.5V to 35V. • 5V Switcher Supply The 5V switching supply regulates the 7.5 to 35V dc input to anominal 5.0V ±0.25V dc (VCC).
Page 91 Theory of Operation (2635A) Detailed Circuit Description The output voltage of the switcher supply is controlled by varying the duty cycle (ON time) of the switching transistor in the controller/switch device A1U9. A1U9 contains the supply reference, oscillator, switch transistor, pulse-width modulator comparator, switch drive circuit, current-limit comparator, current-limit reference, and thermal limit.
Page 92: 31. Digital Kernel
HYDRA Service Manual 2A-29. Inverter Inguard Supply The inverter inguard supply provides three outputs: +5.3V dc (VDD) and -5.4V dc (VSS) for the inguard analog and digital circuitry, and +5.6V dc (VDDR) for the relays. Diodes A1CR5 and A1CR6, and capacitor A1C12 are for the +9.5 volt source, and diodes A1CR7 and capacitor A1C13 are for the -9.5V source.
Page 93 Theory of Operation (2635A) Detailed Circuit Description The Display Reset signal (DRST*) is driven low by A1U2-6 when POR* is low, or it may be driven low by the Microprocessor (A1U1-56) if the instrument firmware needs to reset only the display hardware. For example, the firmware resets the display hardware after the FPGA is loaded at power-up and the Display Clock (DCLK) signal from the FPGA begins normal operation.
Page 94 HYDRA Service Manual The Microprocessor communicates to the Display Controller using a synchronous, three- wire communication interface controlled by hardware in the Microprocessor. Information is communicated to the Display Controller to display user interface menus and measurement data. Details of this communication are described in the Display Controller Theory of Operation in this section.
Page 95 Theory of Operation (2635A) Detailed Circuit Description 2A-34. Address Decoding The four chip-select outputs on the Microprocessor are individual software programmed elements that allow the Microprocessor to select the base address, the size, and the number of wait states for the memory accessed by each output. The FLASH* signal (A1U1-128) enables accesses to 128 kilobytes of Flash Memory (A1U14 and A1U16).
Page 96 HYDRA Service Manual 2A-35. Flash EPROM The Flash EPROM is an electrically erasable and programmable memory that provides storage of instructions for the Microprocessor and measurement calibration data. A switching power supply composed of A1U15, A1T3, A1CR21, and A1C66 through A1C69 generates a nominal +12 volt programming power supply (VPP) when the Microprocessor drives VPPEN high (A1U15-2).
Page 97 Theory of Operation (2635A) Detailed Circuit Description The SRAM* address decode output (A1U1-127) for the 128 kilobytes of NVRAM goes low for any memory access to A1U20 or A1U24. This signal must go through two NAND gates in A1U26 to the NVRAM chip select inputs (A1U20-22 and A1U24-22). This ensures that when the instrument is powered down and A1U10-7 is driven low, A1U20-22 and A1U24-22 will be driven high so that the contents of the NVRAM cannot be changed and the power dissipated by the NVRAM is minimized.
Page 98 HYDRA Service Manual 2A-38. Display/Keyboard Interface The Microprocessor sends information to the Display Processor via a three-wire synchronous communication interface. The detailed description of the DISTX, DISRX, and DSCLK signals may be found in the detailed description of the Display PCA. Note that the DISRX signal is pulled down by resistor A1R1 so that Microprocessor inputs A1U1-49 and A1U1-118 are not floating at any time.
Page 99: Digital I
Theory of Operation (2635A) Detailed Circuit Description Clock Dividers The 12.288-MHz system clock (A1U25-30) is divided down by the Clock Dividers to create the 3.072-MHz Option Clock (OCLK; A1U25-22) and 1.024-MHz Display Clock (DCLK; A1U25-19). The Display Clock is not a square wave; it is low for 2/3 of a cycle and high for the other 1/3.
Page 100 HYDRA Service Manual description of the External Trigger operation may be found in the "External Trigger Input Circuits" section. 2A-40. RS-232 Interface The RS-232 interface is composed of connector A1J4, RS-232 Driver/Receiver A1U13, and the serial communication hardware in Microprocessor A1U1. The serial communication transmit signal (A1U1-80) goes to the RS-232 driver (A1U13- 14), where it is inverted and level shifted so that the RS-232 transmit signal transitions between approximately +5.0 and -5.0V dc.
Page 101: 42. Digital I
Theory of Operation (2635A) Detailed Circuit Description 2A-42. Digital I/O The following paragraphs describe the Digital Input Threshold, Digital Input Buffers, Digital and Alarm Output Drivers, Totalizer Input, and External Trigger Input circuits. 2A-43. Digital Input Threshold The Digital Input Threshold circuit sets the input threshold level for the Digital Input Buffers and the Totalizer Input.
Page 102: 47. External Trigger Input Circuits
HYDRA Service Manual The Totalizer Debounce circuit in the FPGA (A1U25) allows the Microprocessor to select totalizing of either the input signal or the debounced input signal. The buffered Totalizer Input signal (TOTI*) goes into the FPGA at A1U25-12. Inside the FPGA, the totalizer signal is routed to the Totalizer Output (TOTO, A1U25-8) which then goes to a 16-bit counter in the Microprocessor (A1U1-114;...
Page 103 Theory of Operation (2635A) Detailed Circuit Description • Passive filtering of dc voltage and resistance measurements • Active filtering of ac voltage measurements • A/D conversion • Support for direct volts, true rms ac volts, temperature, resistance,and frequency measurements 2A-21...
Page 104 HYDRA Service Manual s13f.eps Figure 2A-3. Analog Simplified SchematicDiagram (2635A) 2A-22...
Page 105 Theory of Operation (2635A) Detailed Circuit Description Table 2A-4. Analog Measurement Processor Pin Descriptions (2635A) Name Description +5.4V supply ACBO AC buffer output (not used) AGND2 Analog ground ACR4 AC buffer range 4 (300V) ACR3 AC buffer range 3 (30V) ACR2 AC buffer range 2 (3V) ACR1...
Page 106: 50. Input Protection
HYDRA Service Manual Table 2A-4. Analog Measurement Processor Pin Descriptions (2635A) (cont) Name Description VREF+ A/D voltage reference plus VREF- A/D voltage reference minus A/D reference amplifier output A/D reference amplifier noninverting input A/D reference amplifier inverting input Passive filter 2 Passive filter 1 plus resistance Passive filter 1 Filter amplifier inverting input...
Page 107: 51. Input Signal Conditioning
Theory of Operation (2635A) Detailed Circuit Description • The open thermocouple detect circuitry is protected against voltagetransient damage by A3Q14 and A3Q15. • When measuring ac volts, the ac buffer is protected by dual-diodeclamp A3CR1 and resistor network A3Z3. • Switching induced transients are also clamped by dual-diodeA3CR4 and capacitor A3C33, and limited by resistor A3R33.
Page 108 HYDRA Service Manual For the 300V range (Figure 2A-4), the HI signal is again scaled by A3Z4. The input is applied to pin 1 of A3Z4, and a 1000:1 divider is formed by the 10-MΩ and 10.01-kΩ resistors when switches S3 and S9 are closed in A3Z4. The attenuated HI input is then sent through internal switch S10 to the passive filter and the a/d converter.
Page 109 Theory of Operation (2635A) Detailed Circuit Description OHMS VOLTAGE SOURCE A3Z4 INTEGRATE REFERENCE REFERENCE – RESISTOR A3R34 HIGH A3K16 A3RT1 & A3R10 A3R11 A3R42 PASSIVE HIGH A3K17 FILTER UNKNOWN INTEGRATE RESISTOR UNKNOWN •R •R s15f.eps Figure 2A-5. Ohms Simplified Schematic (2635A) For the RTD, 300Ω, 3-kΩ, and 30-kΩ...
Page 110 HYDRA Service Manual A3U8 switch S2, and the LO SENSE path of A3R35 and Analog Processor switch S19. Passive filtering is provided by A3C34, A3C27, and portions or all of the DC Filter block. The voltage across the reference resistor for the 300Ω and RTD, 3-kΩ, and 30-kΩ ranges (the 1-kΩ, 10.01-kΩ, and 100.5-kΩ...
Page 111 Theory of Operation (2635A) Detailed Circuit Description INPUT HI A3U6 A3R11 A3C15 A3Z3 A3K15 & 1.111M A3U7 A3C16 A3C31 COVERTER A3Z3 2.776k A3R44 A3Z3 FEEDBACK A3Z3 RESISTOR 115.7 INPUT LO A3R43 s16f.eps Figure 2A-6. AC Buffer Simplified Schematic (2635A) JFETs A3Q3 through A3Q9 select one of the four gain (or attenuation) ranges of the buffer (wide-bandwidth op-amp A3U7.) The four JFET drive signals ACR1 through ACR4 turn the JFETs on at 0V and off at -VAC.
Page 112: 57. Passive And Active Filters
HYDRA Service Manual The output of the buffer is ac-coupled by A3C15 and A3C16 to the true-rms ac-to-dc converter A3U6. Discharge JFET A3Q13 is switched on to remove any excess charge from the coupling capacitors A3C15 and A3C16 between channel measurements. A3C17 provides an averaging function for the converter, and resistor network A3Z1 divides the output by 2.5 before sending the signal to the active ac volts filter.
Page 113 Theory of Operation (2635A) Detailed Circuit Description + REFERENCE (– INPUT) COUNTER REFERENCE A3C13 COMPARATOR INTEGRATE REFERENCE –REFERENCE (+ INPUT) A3Z2 INPUT HI BUFFER INTEGRATOR INTEGRATE INPUT LO INPUT s17f.eps Figure 2A-7. A/D Converter Simplified Schematic (2635A) In both the slow and fast measurement rates, the a/d converter uses its ±300 mV range for most measurement functions and ranges.
Page 114: 59. Inguard Microcontroller Circuitry
HYDRA Service Manual 2A-59. Inguard Microcontroller Circuitry The Microcontroller, A3U9, with its internal program memory and RAM and associated circuitry, controls measurement functions on the A/D Converter PCA and communicates with the Main (outguard) processor. The Microcontroller communicates directly with the A3U8 Analog Measurement Processor using the CLK, CS, AR, and AS lines and can monitor the state of the analog processor using the FC[0:7] lines.
Page 115: Input Connector Pca
Theory of Operation (2635A) Detailed Circuit Description 2A-62. Input Connector PCA The Input Connector assembly, which plugs into the A/D Converter PCA from the rear of the instrument, provides 20 pairs of channel terminals for connecting measurement sensors. This assembly also provides the reference junction temperature sensor circuitry used when making thermocouple measurements.
Page 116: 65. Front Panel Switches
HYDRA Service Manual 2A-65. Front Panel Switches The FPGA scans the 19 Front Panel Switches (A2S1 through A2S18, and A2S21) using only six interface signals (plus the ground connection already available from the power supply). These six signals (SWR1 through SWR6) are connected to bidirectional I/O pins on the FPGA.
Page 117: 68. Watchdog Timer And Reset Circuit
Theory of Operation (2635A) Detailed Circuit Description The second four-bit counter is controlled by an open-drain output on the Display Controller (A2U1-17) and pull-down resistor A2R1. When the beeper (A2LS1) is off, A2U1-17 is pulled to ground by A2R1. This signal is then inverted by A2U6, with A2U6-6 driving the CLR input high to hold the four-bit counter reset.
Page 118 HYDRA Service Manual Once reset, the Display Controller performs a series of self-tests, initializing display memory and holding the DISRX signal high. After DISRX goes low, the Display Controller is ready for communication. On the first command byte from the Microprocessor, the Display Controller responds with a self-test results response.
Page 119: 70. Memory Card Interface Pca
Theory of Operation (2635A) Detailed Circuit Description GRID TIMING 16.56 ms GRID(10) 1.37 ms GRID(9) 1.37 ms … … GRID(1) 1.37 ms GRID(0) 1.37 ms 140 µs s19f.eps Figure 2A-9. Grid Control Signal Timing (2635A) GRID/ANODE TIMING GRID(X) 1 . 3 7 m s -30V 140 µs ANODE(14..0)
Page 120: 71. Main Pca Connector
HYDRA Service Manual 2A-71. Main PCA Connector The Memory Card Interface PCA interfaces to the Main PCA through a 40-pin, right angle connector (A6P2). This connector routes eight bits of the Microprocessor data bus, the lower four bits of the address bus, memory control, interrupt and address decode signals from the Main PCA to the Memory Card Interface PCA.
Page 121: 74. Pcmcia Memory Card Connector
Theory of Operation (2635A) Detailed Circuit Description The Memory Card Controller provides a register based interface for the Microprocessor to use to access data stored on industry standard PCMCIA memory cards. A 26 bit counter controls the address bus (CA<0> through CA<25>) to the PCMCIA Memory Card Connector (A6P1).
Page 122 HYDRA Service Manual ground pins are mated first followed by the reset of the input / output signals with the card detection signals mating last. This sequence is reversed on memory card removal. The PCMCIA Memory Card Connector has a metal shell that is connected to chassis ground to help ensure that the instrument meets EMI/EMC and ESD performance requirements.
Page 123 A Message From Fluke Corporation Some semiconductors and custom IC's can be damaged by electrostatic discharge during handling. This notice explains how you can minimize the chances of destroying such devices 1. Knowing that there is a problem.
Page 124 8. WHEN REMOVING PLUG-IN ASSEMBLIES 5. USE STATIC SHIELDING CONTAINERS FOR HANDLE ONLY BY NON-CONDUCTIVE HANDLING AND TRANSPORT. EDGES AND NEVER TOUCH OPEN EDGE CONNECTOR EXCEPT AT STATIC-FREE WORK STATION. PLACING SHORTING STRIPS ON EDGE CONNECTOR HELPS PROTECT INSTALLED S.S. DEVICES. 6.
Page 125: General Maintenance
Chapter 3 General Maintenance Title Page 3-1. Introduction ..................3-3 3-2. Warranty Repairs and Shipping ............3-3 3-3. General Maintenance................3-3 3-4. Required Equipment ................ 3-3 3-5. Power Requirements ................ 3-3 3-6. Static Safe Handling ................ 3-3 3-7. Servicing Surface-Mount Assemblies..........3-4 3-8.
Page 126 HYDRA Service Manual 3-30. Install the Handle and Mounting Brackets........3-15 3-31. Install the Instrument Case............... 3-15...
Page 127: Introduction
Equipment required for calibration, troubleshooting, and repair of the instrument is listed in Section 4 (Table 4-1.) Refer to the Fluke "Surface Mount Device Soldering Kit" for a list of special tools required to perform circuit assembly repair. (In the USA, call 1-800-526-4731 to order).
Page 128: Servicing Surface-Mount Assemblies
Unique servicing, troubleshooting, and repair techniques are required to support this technology. Refer to Section 5 for additional information. Also, refer to the Fluke "Surface Mount Device Soldering Kit" for a complete discussion of these techniques (in the USA, call 1- 800-526-4731 to order).
Page 129: Line Fuse Replacement
Line Fuse Replacement 3-9. Line Fuse Replacement The line fuse (125 mA, 250V, slow blow, Fluke Part Number 822254) is located on the rear panel. The fuse is in series with the power supply. For replacement, unplug the line cord and remove the fuse holder (with fuse) as shown in Figure 3-1. The instrument is shipped with a replacement fuse loosely secured in the fuse holder.
Page 130: Remove The Instrument Case
HYDRA Service Manual 3-11. Remove the Instrument Case Use the following procedure to remove the instrument case. 1. Make sure the instrument is powered off and disconnected from the power source (ac or dc). 2. Remove the screw from the bottom of the case, and remove the two screws from the rear bezel as shown in Figure 3-2.
Page 131: Removing The Case
General Maintenance Disassembly Procedures MOUNTING SCREW (2) GROUNDING SCREW CASE REAR BEZEL CHASSIS s22f.eps Figure 3-2. Removing the Case...
Page 132: Removing The Handle And Handle Mounting Brackets
HYDRA Service Manual Ω 300V s23f.eps Figure 3-3. Removing the Handle and Handle Mounting Brackets Note The Display PCA provides a space for a center securing screw. If the two tabs are intact, this screw is not necessary. If a tab is broken, a screw can be used as an additional securing device.
Page 133: 2620A And 2625A Assembly Details
General Maintenance Disassembly Procedures s24f.eps Figure 3-4. 2620A and 2625A Assembly Details...
Page 134: 2635A Assembly Details
HYDRA Service Manual s25f.eps Figure 3-5. 2635A Assembly Details 3-10...
Page 135: Remove The Ieee-488 Option (2620A Only)
General Maintenance Disassembly Procedures 3-15. Remove the IEEE-488 Option (2620A Only) Section 7 of this manual provides a detailed removal procedure for the IEEE-488 option. The following removal instructions provide the essentials of this procedure. Parts referenced by letter (e.g., A) are shown in Figure 3-4. If necessary, refer to the complete procedure in Section 7.
Page 136: Remove The Main Pca
HYDRA Service Manual 3-18. Remove the Main PCA With the IEEE-488 option (2620A) and the Memory PCA (2625A) or Memory Card I/F PCA (2635A) removed, the Main PCA (H) can be removed. Parts referenced by letter (e.g., A) are shown in Figure 3-4 (2620A or 2625A) or Figure 3-5 (2635A). Use the following procedure: 1.
Page 137: Disconnect Miscellaneous Chassis Components
General Maintenance Assembly Procedures 3-20. Disconnect Miscellaneous Chassis Components Use the following procedure to disconnect the remaining hardware from the chassis. Parts referenced by letter (e.g., A) are shown in Figure 3-4 (2620A or 2625A) or Figure 3-5 (2635A). 1. Use needle nose pliers to remove the internal connections at the line power plug (X). Remove the ground screw prior to disconnecting the ground wire from the plug.
Page 138: Install The Main Pca
HYDRA Service Manual 3-24. Install the Main PCA 1. Fit the Main PCA (H) so that the chassis guides pass through notches on both sides of the pca. Then slide the pca back until it is snug against the Rear Panel. 2.
Page 139: Install The Memory Card I/F Pca (2635A Only)
General Maintenance Assembly Procedures 3-27. Install the Memory Card I/F PCA (2635A Only) 1. Place the Memory Card I/F PCA (Q) into position so that the three mounting holes line up with the chassis supports located at the front-center of the chassis. 2.
Page 140 HYDRA Service Manual 3-16...
Page 141: Performance Testing And Calibration
Chapter 4 Performance Testing and Calibration Title Page 4-1. Introduction ..................4-3 4-2. Required Equipment................4-3 4-3. Performance Tests ................4-4 4-4. Accuracy Verification Test .............. 4-4 4-5. Channel Integrity Test..............4-4 4-6. Thermocouple Measurement Range Accuracy Test ......4-6 4-7.
Page 142 HYDRA Service Manual 4-30. Updating 2635A Data Bucket Embedded Instrument Firmware..4-27 4-31. Using the PC Compatible Firmware Loader Software ....4-28 4-32. Setup Procedure for Firmware Download ........4-29 4-33. Default Instrument Firmware Download Procedure....4-29 4-34. Using LD2635 Firmware Loader Directly ........4-30...
Page 143: Introduction
10 Hz to 5 kHz Alternate Equipment List (Minimum specifications are the same as in the Standard Equipment List) Instrument Type Recommended Model DMM Calibrator Fluke 5500A Function/Signal Generator Fluke PM5193 or Fluke PM5136 Decade Resistance Source Gen Rad 1433H...
Page 144: Performance Tests
If the instrument fails any of these performance tests, calibration adjustment and/or repair is needed. To perform these tests, use a Fluke 5700A Multifunction Calibrator or equipment that meets the minimum specifications given in Table 4-1.
Page 145 Performance Testing and Calibration Performance Tests Table 4-2. Performance Tests (Voltage, Resistance, and Frequency) DISPLAY ACCURACY FUNCTION RANGE INPUT FREQUENCY (1 Year, 18-28°C) LEVEL  DC Volts 90 mV * short (0) -0.007 0.007  90 mV * 90 mV 89.962 90.038 ...
Page 146: Thermocouple Measurement Range Accuracy Test
HYDRA Service Manual Table 4-2. Performance Tests (Voltage, Resistance, and Frequency) (cont) DISPLAY ACCURACY FUNCTION RANGE INPUT FREQUENCY (1 Year, 18-28°C) LEVEL 300Ω short 0.00 0.09  100Ω 99.92 100.15 3 kΩ short 0.0000 0.0003 3 kΩ 1 kΩ 0.9992 1.0009 30 kΩ...
Page 147: 4-Terminal Resistance Test
Performance Testing and Calibration Performance Tests 1. Ensure that communication parameters (i.e., transmission mode, baud rate, parity, and echo mode) on Hydra and the host are properly configured to send and receive serial data. Refer to Section 4 of the Hydra Users Manual. 2.
Page 148: Thermocouple Temperature Accuracy Test
HYDRA Service Manual 4. Switch the instrument ON. 5. Select the 4-terminal OHMS function, AUTO range, for channel 1 on Hydra. 6. Set the 5700A to output the resistance values listed in Table 4-2 (Use decades of 1.9). 7. On Hydra press MON and ensure the display reads between the minimum and maximum values (inclusive) shown in Table 4-2.
Page 149 Performance Testing and Calibration Performance Tests 2-WIRE (2T) CONNECTION 13 14 15 16 17 18 19 20 SOURCE H L H L H L H L H L H L H L H L H L (4-WIRE) SENSE H L H L H L H L H L H L H L H L H L (4-WIRE) RESISTANCE RTD SOURCE...
Page 150 HYDRA Service Manual Note If other than a K type thermocouple is used, be sure that the instrument is set up for the type of thermocouple used. 3. Reconnect power and switch the instrument ON. 4. Insert the thermocouple and a mercury thermometer (.02 degrees Celsius resolution) in a room temperature bath.
Page 151: Open Thermocouple Response Test
Performance Testing and Calibration Performance Tests 4-9. Open Thermocouple Response Test Use the following procedure to test the open thermocouple response: 1. Switch OFF power to the instrument and disconnect all high voltage inputs. 2. Remove the Input Module from the rear of the instrument. Open the Input Module and connect test leads to the H (high) and L (low) terminals of channel 1.
Page 152: Rtd Temperature Accuracy Test (Using Din/Iec 751)
HYDRA Service Manual 7. The RTD Temperature Accuracy test is complete. However, if you desire to perform this test on Input Module channels (2 through 10), repeat steps 1 through 5 substituting in the appropriate channel number. Note The only type of temperature measurement that can be made on channel 0 is 2-terminal RTD.
Page 153: Digital Input/Output Verification Tests
Performance Testing and Calibration Performance Tests 6. The RTD Temperature Accuracy test is complete. However, if you desire to perform this test on any other channel (0 or 2 through 20), repeat steps 1 through 5, substituting the appropriate channel number. Note The only type of temperature measurement that can be made on channel 0 is 2-terminal RTD.
Page 154: Digital Input Test
HYDRA Service Manual Send the following commands to Hydra in sequence, and measure that the correct Digital Output line measures greater than +3.8V dc (HIGH state.) DO_LEVEL 0,1 <CR> Verify that output 0 measures a HIGH state. DO_LEVEL 1,1 <CR> Verify that output 1 measures a HIGH state.
Page 155: Totalizer Sensitivity Test
Performance Testing and Calibration Performance Tests computer). The host must send commands to Hydra to control the digital line for this test. 1. Ensure that communication parameters (i.e., transmission mode, baud rate, parity, and echo mode) on Hydra and the host are properly configured to send and receive serial data.
Page 156: Dedicated Alarm Output Test
HYDRA Service Manual 3. Verify that Hydra is still in the total measuring mode. If not, press the TOTAL button. Reset the totalizer count shown on the display by pressing the SHIFT and TOTAL(ZERO) buttons. The Hydra display should now show a value of 0. ∑...
Page 157: Dedicated Alarms Test
Performance Testing and Calibration Performance Tests ALARM OUTPUTS DIGITAL I/O ALARM OUTPUT CONNECTOR + – 1 2 3 TR Σ + – 1 2 3 TR 0 1 2 3 4 5 6 7 +30V 9-16 V DC PWR 13 14 15 16 17 18 19 20 SOURCE H L H L H L H L H L H L H L H L H L (4-WIRE)
Page 158: External Trigger Input Test
HYDRA Service Manual 4-19. External Trigger Input Test The External Trigger Input Test verifies that the rear panel trigger input of Hydra is functioning properly. 1. Switch OFF power to the instrument and disconnect all high voltage inputs. 2. Remove the eight-terminal Alarm Output connector from the rear of Hydra and all external connections to it.
Page 159: Using Hydra Starter Calibration Software
Performance Testing and Calibration Calibration Activate calibration mode by pressing and holding the CAL Enable button (front panel) for approximately 4 seconds. Release the button after Hydra beeps and the CAL annunciator lights. Note The CAL Enable button is located on the right side of the display and is recessed beneath a calibration seal.
Page 160: Using Hydra Starter Calibration Software
HYDRA Service Manual To provide accuracy at full range, calibration is not recommended below one-third of full range (10000 counts). Table 4-8. Calibration Mode Computer Interface Commands Command Description Cal x Start calibration of a new function. Function to calibrate ohms Frequency CAL_CLR...
Page 161: Calibration Procedure Using Starter
Performance Testing and Calibration Calibration 3. From the CAL directory on the PC, type CAL. Then press any key to start the program and access the SETUP menu. 4. On Hydra, press POWER ON. After the initialization process has concluded, use the following procedure to set up communications: a.
Page 162: Using A Terminal
HYDRA Service Manual 4-24. Using a Terminal This procedure can be used with either a terminal or a computer running a terminal emulation program. 4-25. Setup Procedure Using a Terminal. Use the following procedure to set up Hydra and the PC: 1.
Page 163 Performance Testing and Calibration Calibration Once the calibrator output has been set to Hydra, the CAL_STEP? query performs the calibration step and returns the calibrated value of the input. The response to CAL_STEP? must be received before each new step can begin. With some steps, a noticeable delay may be encountered.
Page 164: Reference Junction Calibration
HYDRA Service Manual Note The 300 k Ω , 3 M Ω , and 10 M Ω ranges are sensitive to noise. Any movement of the input leads can cause noisy readings. Use shielded leads and verify these two calibration points at the conclusion of calibration. Table 4-10.
Page 165: Concluding Calibration
Performance Testing and Calibration Calibration 4-WIRE (4T) CONNECTION 13 14 15 16 17 18 19 20 SOURCE H L H L H L H L H L H L H L H L H L (4-WIRE) HYDRA INPUT MODULE SENSE H L H L H L H L H L H L H L H L H L (4-WIRE) DECADE...
Page 166 HYDRA Service Manual 13 14 15 16 17 18 19 20 SOURCE H L H L H L H L H L H L H L H L H L (4-WIRE) HYDRA INPUT MODULE SENSE H L H L H L H L H L H L H L H L H L (4-WIRE) 5700A OUTPUT...
Page 167: Updating 2635A Data Bucket Embedded Instrument Firmware
Bucket firmware may be obtained from either your local Fluke authorized service center or the Fluke factory. The local service centers are listed in Section 6 of this manual. Contact the one nearest you. To request the "2635A Embedded Firmware Memory Loader"...
Page 168: Using The Pc Compatible Firmware Loader Software
HYDRA Service Manual Table 4-12. 4-Wire Ohms Calibration (5700A) Command Action CAL 3 Puts Hydra in OHMS Calibration Note With the following CAL_REF commands, send the actual resistance value (e.g., xxx.xxxxx) displayed by the 5700A. Source 190Ω from the 5700A. Then wait 4 seconds for the 5700A to settle. CAL_REF xxx.xxxxx CAL_STEP? Hydra computes calibration constant 15 and returns the calibrated reading.
Page 169: Setup Procedure For Firmware Download
Performance Testing and Calibration Updating 2635A Data Bucket Embedded Instrument Firmware Firmware downloading may be accomplished by using either of the two methods that are described in the following paragraphs. • Default Instrument Firmware Download Procedure • Using LD2635 Firmware Loader Directly Table 4-13.
Page 170: Using Ld2635 Firmware Loader Directly
HYDRA Service Manual 1. If it is important to retain the channel programming information in the instrument, store a copy of the instrument configuration setup on a memory card. Refer to section on "Using SETUP STORE" in section 3 of the 2635A Data Bucket Users Manual.
Page 171: Diagnostic Testing And Troubleshooting (2620A/2625A)
Chapter 5 Diagnostic Testing and Troubleshooting (2620A/2625A) Title Page 5-1. Introduction ..................5-3 5-2. Servicing Surface-Mount Assemblies ..........5-3 5-3. Error Codes................... 5-4 5-4. General Troubleshooting Procedures ........... 5-6 5-5. Power Supply Troubleshooting............5-8 5-6. Raw DC Supply................5-8 5-7. Power Fail Detection................
Page 172 HYDRA Service Manual 5-28. Failure to Detect Memory PCA........... 5-29 5-29. Failure to Store Data..............5-29...
Page 173: Introduction
SMT. It is not recommended that repair be attempted based only on the information presented here. Refer to the Fluke "Surface Mount Device Soldering Kit" for a complete demonstration and discussion of these techniques. (In the USA, call 1-800- 526-4731 to order.)
Page 174: Error Codes
An oxidized pca padcauses the solder to wick up the component lead, leaving littlesolder on the pad itself. Refer to the Fluke "Surface Mount Device Soldering Kit" for a complete discussion of these techniques.
Page 175 Diagnostic Testing and Troubleshooting (2620A/2625A) Error Codes Table 5-1. Error Codes Error Description ROM (A1U8) checksum error External RAM (A1U3) test failed Internal RAM (A1U4) test failed Display power-up test failure Display not responding Instrument configuration corrupted EEPROM instrument configuration corrupted EEPROM calibration data corrupted A/D not responding A/D ROM test failure (A3U9)
Page 176: General Troubleshooting Procedures
HYDRA Service Manual Table 5-1. Error Codes (cont) Error Description Error b A/D RAM test failure Complementary patterns are alternately written to and read from each location of the 256 bytes of RAM internal to the 6301Y Microcomputer (A3U9). Error C A/D self test failed The Analog Measurement Processor (A3U8) is programmed to do self test measurements.
Page 177: Test Point Locator, Main Pca (A1)
Diagnostic Testing and Troubleshooting (2620A/2625A) Power Supply Troubleshooting A1TP8 A1TP4 A1TP31 A1TP17 A1TP15 A1TP16 A1TP6 A1TP30 Display A1TP11 Connector A1TP32 A1TP1 A1TP5 Option A1TP3 Interface A 1 T P 3 1 A1TP10 A1TP13 A1TP14 A1TP18 A1TP12 RS-232 A1TP19 A1TP9 A1TP7 Connector A1TP2 A1TP20...
Page 178: 5-Volt Switching Supply
HYDRA Service Manual 5-5. Power Supply Troubleshooting Warning To avoid electric shock, disconnect all channelinputs from the instrument before performing anytroubleshooting operations. 5-6. Raw DC Supply With the instrument connected to line power (120V ac, 60 Hz) and turned ON, check for approximately 14V dc between A1TP1 (GND) and the "+"...
Page 179: 5-Volt Switching Supply
Diagnostic Testing and Troubleshooting (2620A/2625A) Power Supply Troubleshooting U9-7 and T2-2 2 µS/DIV 5V/DIV Normal Load s33f.eps Figure 5-2. 5-Volt Switching Supply If no square wave is present at A1U9-7, the oscillator can be checked by looking at the signal at A1U9-3. The oscilloscope should be ac-coupled for this measurement. This waveform should be a sawtooth signal with an amplitude of 0.6V p-p and a period of approximately 14 us.
Page 180 HYDRA Service Manual For the inverter to operate, the 110-kHz oscillator must be operating properly. If the signal at A1U22-3 is missing, begin by checking the voltage at A1TP7. The voltage should be about 5.1V dc. Then, using an oscilloscope, check for a square wave signal at A1U23-9 and a square wave signal at A1U23-8.
Page 181: Inverter Fet Drive Signals
Diagnostic Testing and Troubleshooting (2620A/2625A) Power Supply Troubleshooting TP9 AND TP10 2V/DIV 2µS/DIV FET GATE SIGNAL Q7, Q8, OR T1-1 OR -3 2V/DIV 2µS/DIV FET DRAIN SIGNAL s34f.eps Figure 5-3. Inverter FET Drive Signals 5-11...
Page 182: Analog Troubleshooting
HYDRA Service Manual 5-10. Analog Troubleshooting Warning To avoid electric shock, disconnect all channelinputs from the instrument before performing anytroubleshooting operations. Refer to Figure 5-4 and Figure 5-5 for test point locations on the A/D Converter PCA. First, check for analog-related errors displayed at power up. An ’Error 9’ means that the Main Microprocessor A1U4 is not able to communicate with the A/D Microcontroller A3U9.
Page 183 Diagnostic Testing and Troubleshooting (2620A/2625A) Analog Troubleshooting Table 5-3. Power Supply Troubleshooting Guide Symptom Fault Line fuse blows. - Shorted A1CR2 or A1CR3. - Shorted A1CR10. - Shorted A1C7. - Shorted A1C26. Supply voltage for A1U23 and A1U22 is greater than Input-to-output short of A1U19.
Page 184 HYDRA Service Manual Table 5-3. Power Supply Troubleshooting Guide (cont) Symptom Fault A1U18 hot. Shorted A1C32 A1U18 oscillates. Open A1C32. A1U19 oscillates. Open A1C34. A1U19 very hot. - Shorted A1U22 (VCC to VSS). - Shorted A1U23 (VCC to VSS). A1U19 hot. Shorted A1C34.
Page 185: Test Points, A/D Converter Pca (A3, A3U9)
Diagnostic Testing and Troubleshooting (2620A/2625A) Analog Troubleshooting A3TP2 A3TP8 A3TP3 A3TP7 A3TP4 A3TP1 A/D Microcontroller A3TP5 RMS Converter Network A3TP13 A3TP6 A3TP10 A3TP11 RMS Converter A3TP12 A3TP9 AC Buffer Analog Zener Reference Measurement Intergrate Resistors, Reference Divider Processor AC Divider Divider Network Network...
Page 186 HYDRA Service Manual A3TP2 A3TP8 A3TP3 A3TP7 A3TP4 A3TP1 A/D Microcontroller A3TP5 RMS Converter Network A3TP13 A3TP6 A3TP10 A3TP11 RMS Converter A3TP12 A3TP9 AC Buffer Analog Measurement Zener Reference Processor Intergrate Resistors, Reference Divider AC Divider Divider Network Network (DC/OHMS) 60 K13S 59 K13R 58 K6S...
Page 187: Integrator Output
Diagnostic Testing and Troubleshooting (2620A/2625A) Analog Troubleshooting A3TP13 TO A3TP9 1V/DIV 5 mS/DIV s37f.eps Figure 5-6. Integrator Output 5-11. DC Volts Troubleshooting Setup the instrument to measure a specific channel on the 300 mV or 3V range, and apply an input to that channel. Then trace the HI signal (referenced to the input channel LO terminal) as described in Table 5-4.
Page 188: Ohms Troubleshooting
HYDRA Service Manual Table 5-5. AC Volts HI Troubleshooting Checkpoint Signal Description Possible Fault A3R11 HI Input A3K1 through A3K14, A3U4, A3U5, A3U11, A3U12 A3L1, A3L2, A3L3 A3Z3 pin 1 Input A3R11, A3C31, A3K15 A3U6 pin 13 Amplified (X 2.5) input A3U7, A3Z3, A3Q3 through A3Q9, A3C15, A3C16, A3R24, A3A25, A3R26, A3R27, A3R28, A3C23, A3U6, A3Q13, A3U8...
Page 189: Digital Kernel Troubleshooting
Diagnostic Testing and Troubleshooting (2620A/2625A) Digital Kernel Troubleshooting 5-14. Digital Kernel Troubleshooting At power-up, if the display does not light or lights up and fails to report errors or begin operation, use the following troubleshooting procedures. First check the state of SWR1 (A1U4-21). If this status line is less than 0.8V, basic processor operation is intact.
Page 190: Microprocessor Timing
HYDRA Service Manual Figure 5-7 shows the timing relationships of the 6303Y Microprocessor lines LIR* and WR* to the system clock (E) and the address lines A0..A15. The ROM and NVRAM Chip Enables correspond to the active (low) region shown for the address lines. If the instrument powers up without any errors, but does not recognize front-panel button presses or computer interface commands, the problem may be in the Counter/Timer (A1U2).
Page 191: Digital And Alarm Output Troubleshooting
Diagnostic Testing and Troubleshooting (2620A/2625A) Digital and Alarm Output Troubleshooting 5-15. Digital and Alarm Output Troubleshooting Power up Hydra while holding down the CANCL button to reset the instrument configuration. Since the structure of the eight Digital Outputs and four Alarm Outputs is very similar, the troubleshooting procedure presented here does not refer to specific device and pin numbers.
Page 192: Test Points, Display Pca (A2)
HYDRA Service Manual A2TP2 A2TP3 A2TP6 A2TP1 A2TP5 A2TP4 (S21) (S1) (S3) (S5) (S7) (S9) (S11) (S13) (S15) (S17) (S2) (S4) (S6) (S8) (S10) (S12) (S14) (S16) (S18) A2TP2 A2TP3 A2TP6 A2TP1 A2TP5 A2TP4 TEST POINT LOCATIONS (DISPLAY PCA) s39f.eps Figure 5-8.
Page 193: Display Controller To Microprocessor Signals
Diagnostic Testing and Troubleshooting (2620A/2625A) Display Assembly Troubleshooting 5-18. Display Assembly Troubleshooting The following discussion is helpful if it has been determined that the Display Assembly is faulty. Refer to Figure 5-8 for Display PCA test points. This initial determination may not be arrived at easily, since an improperly operating display may be the result of a hardware or software problem that is not a direct functional part of the Display Assembly.
Page 194 HYDRA Service Manual SET FUNC REVIEW REM SCAN Ω x1 k s41f.eps Figure 5-10. Display Test Pattern #1 AUTO MON Mx+B ALARM LAST °C °F RO AC DC LIMIT HI s42f.eps Figure 5-11. Display Test Pattern #2 When a Hydra display is initially powered up, all display segments should come on automatically.
Page 195: Variations In The Display
Diagnostic Testing and Troubleshooting (2620A/2625A) Variations in the Display 5. Verify that the DISRX signal (A2U1-39) goes low after RESET (A2U1-1) goes low. If this sequence does not occur, communication to the Microprocessor is held off with the DISRX signal high. If DISRX stays high but is not shorted to VCC, A2U1 must be faulty.
Page 196: Calibration Failures
HYDRA Service Manual 5-20. Calibration Failures 5-21. Introduction Calibration of Hydra through the computer interface is described in Section 4 of this manual. Generally, a calibration failure is indicated by a Device Dependent Error and a "!>" prompt after a CAL_STEP? command if the RS-232 interface is being used. If the IEEE-488 interface is being used, the Device Dependent Error may be detected by reading the Event Status Register (see the Hydra User Manual).
Page 197 Diagnostic Testing and Troubleshooting (2620A/2625A) Calibration Failures Note During calibration, the measurement rateis selected automatically as required by thecalibration step. Table 5-9 or Table 5-10 may be useful in isolating a calibration problem to specific components. Table 5-9 can be used with a Hydra having a main software version number of 5.4 or higher.
Page 198: Retrieving Calibration Constants
HYDRA Service Manual 5-23. Retrieving Calibration Constants If a calibration error is suspected, the stored constant can be retrieved and verified over the computer interface. Acceptable calibration constants for each function and range are listed in Table 5-9 (software version 5.4 and higher) or 5-10 (software versions lower than 5.4.) Retrieve the constant with the following command: CAL_CONST? xx (where xx denotes the calibration constant number)
Page 199: Ieee-488 Interface Pca (A5) Troubleshooting
Diagnostic Testing and Troubleshooting (2620A/2625A) IEEE-488 Interface PCA (A5) Troubleshooting The following command may be used to program the serial number into the EEPROM: SERIAL XXXXXXX (xxxxxxx denotes the 7-digit number. Leading zeros The serial number of the instrument can be accessed by using the "SERIAL?" command. The response will be "0"...
Page 200 HYDRA Service Manual While the instrument is scanning, check that data is being stored correctly. Use an oscilloscope to monitor activity on the 7 outputs of the Byte Counter (A6U3) and the 11 outputs of the Page Register (A6U1 and A6U4). Since the repetition rate is fairly low, it may be necessary to use a storage oscilloscope to capture the activity.
Page 201 Chapter 5A Diagnostic Testing and Troubleshooting (2635A) Title Page 5A-1. Introduction ..................5A-3 5A-2. Servicing Surface-Mount Assemblies ..........5A-3 5A-3. Error Codes................... 5A-4 5A-4. General Troubleshooting Procedures ........... 5A-6 5A-5. Power Supply Troubleshooting............5A-8 5A-6. Raw DC Supply................5A-8 5A-7. Power Fail Detection................
Page 202 HYDRA Service Manual 5A-28. Failure to Detect Insertion of Memory Card ....... 5A-31 5A-29. Failure to Power Card / Illuminate the Busy Led ......5A-31 5A-30. Failure to Illuminate the Battery Led .......... 5A-31 5A-31. Failure to Write to Memory Card ..........5A-32 5A-32.
Page 203: Introduction
SMT. It is not recommended that repair be attempted based only on the information presented here. Refer to the Fluke "Surface Mount Device Soldering Kit" for a complete demonstration and discussion of these techniques. (In the USA, call 1-800- 526-4731 to order.)
Page 204: Error Codes
An oxidized pca padcauses the solder to wick up the component lead, leaving littlesolder on the pad itself. Refer to the Fluke "Surface Mount Device Soldering Kit" for a complete discussion of these techniques.
Page 205: 3. Error Codes
Diagnostic Testing and Troubleshooting (2635A) Error Codes Table 5A-1. Error Codes (2635A) Error Description Boot Firmware (A1U14 and A1U16) Checksum Error Instrument Firmware (A1U14 and A1U16) Checksum Error NVRAM (A1U20 and A1U24) Test Failed Display Power-up Test Failure Display Not Responding Instrument Configuration Corrupted Instrument Calibration Data Corrupted Instrument Not Calibrated...
Page 206: General Troubleshooting Procedures
HYDRA Service Manual Table 5A-1. Error Codes (2635A) (cont) Error Description Error 9 A/D Converter Not Responding This error is displayed if communication cannot be established with the 6301Y Microcomputer (A3U9). Error A A/D Converter ROM Test Failure (A3U9) All bytes of internal ROM for the 6301Y Microcomputer (A3U9) (including the checksum byte) are summed.
Page 207: 4. General Troubleshooting Procedures
Diagnostic Testing and Troubleshooting (2635A) General Troubleshooting Procedures A1TP30 A1TP4 A1TP32 A1TP5 A1TP31 A1TP10 A1TP6 A1TP18 A1TP8 A1TP11 A1TP3 A1TP1 A1TP7 A1TP13 A1TP2 A1TP14 A1TP20 A1TP9 A1TP15 A1TP12 V DD TOUT2 TIN2 TOUT1 V DD TIN1 IACK1 IACK6 IACK7 V DD A1AU1 MICROPROCESSOR XTAL EXTAL...
Page 208: Power Supply Troubleshooting
HYDRA Service Manual Refer to the Schematic Diagrams in Section 8 during the following troubleshooting instructions. Also, these diagrams are useful in troubleshooting circuits not specifically covered here. 5A-5. Power Supply Troubleshooting Warning To avoid electric shock, disconnect all channel inputs from the instrument before performing any troubleshooting operations.
Page 209: Inverter
Diagnostic Testing and Troubleshooting (2635A) Power Supply Troubleshooting 5A-9. Inverter Use an oscilloscope to troubleshoot the inverter supply. The outputs of the inverter supply are -5V dc (VEE), -30V dc (VLOAD), and 5.4V ac (FIL1 and FIL2) outguard, and +5.3V dc (VDD), -5.4V dc (VSS), and +5.6V dc (VDDR) inguard. Refer to Figure 5A-3.
Page 210 HYDRA Service Manual TP9 AND TP10 2V/DIV 2µS/DIV FET GATE SIGNAL Q7, Q8, OR T1-1 OR -3 2V/DIV 2µS/DIV FET DRAIN SIGNAL s45f.eps Figure 5A-3. Inverter FET Drive Signals (2635A) 5A-10...
Page 211: 10. Analog Troubleshooting
Diagnostic Testing and Troubleshooting (2635A) Analog Troubleshooting Note When making voltage measurements in the invertercircuit, remember that there are two separategrounds. The outguard ground is the ’GND’ testpoint (A1TP1), and the inguard ground is the’COM’ test point (A1TP30). The inguard regulator circuits for VDD and VSS have current limits. Shorts and heavy loads between VDD and COM, VSS and COM, and VDD and VSS will cause one or both supplies to go into current limit.
Page 212 HYDRA Service Manual Table 5A-3. Power Supply Troubleshooting Guide (2635A) Symptom Fault Line fuse blows. - Shorted A1CR2 or A1CR3. - Shorted A1CR10. - Shorted A1C7. - Shorted A1C26. Supply voltage for A1U23 and A1U22 is greater than Input-to-output short of A1U19. This fault may have 7V (7 to 30V).
Page 213 Diagnostic Testing and Troubleshooting (2635A) Analog Troubleshooting Table 5A-3. Power Supply Troubleshooting Guide (2635A) (cont) Symptom Fault A1U18 hot. Shorted A1C32 A1U18 oscillates. Open A1C32. A1U19 oscillates. Open A1C34. A1U19 very hot. - Shorted A1U22 (VCC to VSS). - Shorted A1U23 (VCC to VSS). A1U19 hot.
Page 214 HYDRA Service Manual A3TP2 A3TP8 A3TP3 A3TP7 A3TP4 A3TP1 A/D Microcontroller A3TP5 RMS Converter Network A3TP13 A3TP6 A3TP10 A3TP11 RMS Converter A3TP12 A3TP9 AC Buffer Analog Measurement Zener Reference Processor Intergrate Resistors, Reference Divider AC Divider Divider Network Network (DC/OHMS) 60 K13S 59 K13R 58 K6S...
Page 215: 5. Test Points, A/D Converter Pca (A3U9) (2635A)
Diagnostic Testing and Troubleshooting (2635A) Analog Troubleshooting A3TP2 A3TP8 A3TP3 A3TP7 A3TP4 A3TP1 A/D Microcontroller A3TP5 RMS Converter Network A3TP13 A3TP6 A3TP10 A3TP11 RMS Converter A3TP12 A3TP9 AC Buffer Analog Zener Reference Measurement Intergrate Resistors, Reference Divider Processor AC Divider Divider Network Network...
Page 216: Dc Volts Troubleshooting
HYDRA Service Manual Lack of outguard-to-inguard communication activity may be due to improper operation of circuit elements other than A3U9. Using a high input impedance oscilloscope or timer/counter, check for proper Analog Processor (A3U8) crystal oscillator operation. A 3.84-MHz sine wave (260 ns period) should be present at A3U8 pin 37 with respect to A3TP9.
Page 217: Ac Volts Troubleshooting
Diagnostic Testing and Troubleshooting (2635A) Analog Troubleshooting Table 5A-4. DC Volts HI Troubleshooting (2635A) Checkpoint Signal Description Possible Fault A3R11 HI Input A3K1 through A3K14, A3U4, A3U5, A3U11, A3U12, A3L1, A3L2, A3L3 A3U8 pin 23 Input A3R11, A3K17, A3R42, A3C32 A3U8 pin 58 Input, DC filter output A3U8, A3Q2...
Page 218: 14. Digital Kernel Troubleshooting
HYDRA Service Manual Table 5A-6. Ohms Open-Circuit Voltage (2635A) Range Voltage 300Ω 3 kΩ 1.3V 30 kΩ 1.3V 300 kΩ 3 MΩ 10 MΩ Table 5A-7. Ohms HI Troubleshooting (2635A) Checkpoint Signal Description Possible Fault A3U8 pin 14 Ohms Source A3U8 A3R10 HI SRC Ohms Source...
Page 219: 14. Digital Kernel Troubleshooting
Diagnostic Testing and Troubleshooting (2635A) Digital Kernel Troubleshooting During instrument power-up, the RESET* and HALT* signals are held low for 140 to 280 milliseconds after the VCC power supply is greater than 4.65 volts dc. Before the Microprocessor can begin execution of the firmware stored in the Flash Memory, the reset circuit must release the RESET* and HALT* signals (A1U2-11 and A1U2-8 respectively) and allow them to go high.
Page 220 HYDRA Service Manual If the instrument powers up and displays ’boot,’ it is likely that one of the memory test errors (Errors 1 through 3) was detected. To determine what the error status was, connect a terminal or computer to the RS-232 interface (19200 baud, 8 data bits, no parity). Assuming that the RS-232 interface is functional, send a carriage return or line feed character to the instrument, and it should send back a prompt that shows a number followed by a ’>’...
Page 221: 15. Digital And Alarm Output Troubleshooting
Diagnostic Testing and Troubleshooting (2635A) Digital and Alarm Output Troubleshooting Figure 5A-7 shows the timing relationships of the MC68302 Microprocessor address, data, and memory control signals used for memory read and write cycles. The chip selects from the Microprocessor (FLASH*, SRAM*, XMCARD*, and I/O*) are decoded internally from the address bus and the address strobe (AS*) signal.
Page 222 HYDRA Service Manual S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 W W W W S5 S6 S7 A1 – A23 DTACK D8 – D15 D0 – D7 READ WRITE SLOW READ...
Page 223: 17. Totalizer Troubleshooting
Diagnostic Testing and Troubleshooting (2635A) Totalizer Troubleshooting If the Input Buffer does not function correctly, the problem is probably A1Z1, A1Z3, or the associated comparator (A1U3 or A1U4). If the Input Buffer functions correctly, but Hydra is not able to read the state of the Digital Input correctly, the problem is most likely the FPGA (A1U25).
Page 224 HYDRA Service Manual A2TP2 A2TP3 A2TP6 A2TP1 A2TP5 A2TP4 (S21) (S1) (S3) (S5) (S7) (S9) (S11) (S13) (S15) (S17) (S2) (S4) (S6) (S8) (S10) (S12) (S14) (S16) (S18) A2TP2 A2TP3 A2TP6 A2TP1 A2TP5 A2TP4 TEST POINT LOCATIONS (DISPLAY PCA) s50f.eps Figure 5A-8.
Page 225: Display Test Pattern #2
Diagnostic Testing and Troubleshooting (2635A) Display Assembly Troubleshooting. Table 5A-8. Display Initialization (2635A) A2TP4 DTEST* A2TP5 LTE* POWER-UP DISPLAY INITIALIZATION All Segments OFF All Segments ON (default) Display Test Pattern #1 Display Test Pattern #2 DSCLK DISTX BIT 7 BIT 6 BIT 5 BIT 4 BIT 3...
Page 226: 19. Variations In The Display
HYDRA Service Manual 2. Check the filament drive signals FIL1 and FIL2; these connect to the last two pins on each end of A2DS1. These signals should be 5.4V ac with FIL2 biased to be about 6.8V dc higher than the VLOAD supply (nominally a -23.2V dc level). FIL1 and FIL2 should be 180 degrees out of phase.
Page 227: 20. Calibration Failures
Diagnostic Testing and Troubleshooting (2635A) Calibration Failures 2. Wait a moment for the instrument to beep, then release SHIFT. The entire display will now stay on until you are ready to deactivate it. 3. At the end of the activation period, press any button on the front panel; the instrument resumes the mode in effect prior to the power interruption (Active or Inactive.) 5A-20.
Page 228 HYDRA Service Manual Basic dc measurements depend on the zener reference (A3VR1), reference divider network (A3Z2), and integrate resistors (A3Z2). Resistance measurements and dc measurements above three volts additionally depend on the resistors in the dc divider network (A3Z4). AC measurements depend on the ac divider network (A3Z3), ac buffer (A3U7), and RMS converter (A3U6), as well as the basic dc measurement components.
Page 229: Retrieving Calibration Constants
Diagnostic Testing and Troubleshooting (2635A) Calibration Failures 5A-23. Retrieving Calibration Constants If a calibration error is suspected, the stored constant can be retrieved and verified over the computer interface. Acceptable calibration constants for each function and range are listed in Table 5A-9. Retrieve the constant with the following command: CAL_CONST? xx (where xx denotes the calibration constant number) The entire calibration of the Hydra Databucket can be retrieved from the instrument in...
Page 230: 25. Memory Card I/F Pca (A6) Troubleshooting
HYDRA Service Manual The following command may be used to program the serial number into the FLASH Memory: SERIAL XXXXXXX (xxxxxxx denotes the 7-digit number. Leading zeros must be entered. Note: once entered, the number cannot be changed.) The serial number of the instrument can be accessed by using the “SERIAL?” command. The response will be “0”...
Page 231: Failure To Detect Insertion Of Memory Card
Diagnostic Testing and Troubleshooting (2635A) Memory Card I/F PCA (A6) Troubleshooting. 5A-28. Failure to Detect Insertion of Memory Card When a Memory Card is inserted into the Memory Card Interface, the card detect signals (CD1 and CD2; A6U1-19 and A6U1-21) are driven low. Verify that the Memory Card Controller detects this and interrupts the Microprocessor (A1U1) by driving the MCINT* signal (A6U1-60) low.
Page 232: Failure To Write To Memory Card
HYDRA Service Manual 5A-31. Failure to Write to Memory Card The installed memory card controls the state of the write protect (WP) signal that is an input to the Memory Card Controller (A6U1-22). This signal must be near 0 volts dc when the memory card is powered up and any operation requiring write access to the memory card is done.
Page 233 Diagnostic Testing and Troubleshooting (2635A) Memory Card I/F PCA (A6) Troubleshooting. • With ’CtS’ (Clear to Send) displayed, use the UP or DOWN arrow key to select ’OFF’. Then press ENTER. • With ’ECHO’ displayed, use the UP or DOWN arrow key to select ’ON’. Then press ENTER.
Page 234 HYDRA Service Manual 5A-34...
Page 235: List Of Replaceable Parts
Chapter 6 List of Replaceable Parts Title Page 6-1. Introduction ..................6-3 6-2. How to Obtain Parts ................6-3 6-3. Manual Status Information..............6-3 6-4. Newer Instruments................6-4 6-5. Service Centers..................6-4 6-6.......................6-4...
Page 236 HYDRA Service Manual...
Page 237: Introduction
Electrical components may be ordered directly from the manufacturer by using the manufacturers part number, or from the Fluke Corporation and its authorized representatives by using the part number under the heading FLUKE STOCK NO. In the U.S., order directly from the Fluke Parts Dept. by calling 1-800-526-4731. Parts price information is available from the Fluke Corporation or its representatives.
Page 238: Newer Instruments
6-5. Service Centers To locate an authorized service center, call Fluke using any of the phone numbers listed below, or visit us on the World Wide Web: www.fluke.com 1-800-443-5853 in U.S.A and Canada...
Page 239: 2620A/2625A Final Assembly
List of Replaceable Parts Service Centers Table 6-1. 2620A/2625A Final Assembly Reference Fluke Stock Description Tot Qty Notes Designator MAIN PCA 814186 DISPLAY PCA 814914 A/D CONVERTER PCA 814202 ANALOG INPUT PCA 814210 IEEE-488 INTERFACE PCA 872593 MEMORY PCA 886135 F1,2 FUSE,5X20MM,0.125A,250V,SLOW...
Page 240 HYDRA Service Manual Table 6-1. 2620A/2625A Final Assembly (cont) Reference Fluke Stock Description Tot Qty Notes Designator MP80 HYDRA STARTER SOFTWARE 890645 MP99 T/C CABLE,ASSY 871512 MP101 LABEL,VINYL,1.500,.312 844712 TRANSFORMER,POWER,100-240V 931105 HYDRA MANUAL SET (ENGLISH) 886015 HYDRA (STARTERS PKG) APPLICATION SOFTWA 890632 HYDRA &...
Page 241 List of Replaceable Parts Service Centers 2620A/2625A T&B (1 of 3) s55f.eps Figure 6-1. 2620A/2625A Final Assembly...
Page 242 HYDRA Service Manual W2 (Ref) H52 (Ref) A1 (Ref) Bottom View 2620A/2625A T&B (2 of 3) s56f.eps Figure 6-1. 2620A/2625A Final Assembly (cont)
Page 243 List of Replaceable Parts Service Centers T1 (Ref) H52 (Ref) Top View 2620A/2625A T&B (3 of 3) s57f.eps Figure 6-1. 2620A/2625A Final Assembly (cont)
Page 244 HYDRA Service Manual MP66 MP67 2620A-100 s58f.eps Figure 6-1. 2620A/2625A Final Assembly (cont) 6-10...
Page 245: 2635A Final Assembly
List of Replaceable Parts Service Centers Table 6-2. 2635A Final Assembly Reference Fluke Stock Description Tot Qty Notes Designator MAIN PCA 925669 DISPLAY PCA 814194 A/C CONVERTER PCA 814202 ANALOG INPUT PCA 814210 MEMORY CARD I/F PCA 931977 F1,2 FUSE,5X20MM,0.125A,250V,SLOW 822254 SCREW,FH,P,LOCK,STL,8-32,.375...
Page 246 931113 CORD,LINE,5-15/IEC,3-18AWG,SVT,7.5 FT 284174 1. FOR 256KB MEMORY CARD ORDER FLUKE PN 927512. FOR 1 MB MEMORY CARD ORDER FLUKE PN 927517 FOR 2 MB MEMORY CARD ORDER FLUKE PN 944313. 2. INCLUDES: HYDRA USERS MANUAL (885988), AND HYDRA QUICK SETUP CARD (895883).
Page 247 List of Replaceable Parts Service Centers 2635A T&B (1 of 3) s59f.eps Figure 6-2. 2635A Final Assembly 6-13...
Page 248 HYDRA Service Manual Part of W2 MP102 (Ref) (Cable Assembly) Bottom View 2635A T&B (2 of 3) s60f.eps Figure 6-2. 2635A Final Assembly (cont) 6-14...
Page 249 List of Replaceable Parts Service Centers T1 (Ref) Top View 2635A T&B (3 of 3) s61f.eps Figure 6-2. 2635A Final Assembly (cont) 6-15...
Page 250 HYDRA Service Manual MP66 MP67 2620A-100 s62f.eps Figure 6-2. 2635A Final Assembly (cont) 6-16...
Page 251 List of Replaceable Parts Service Centers Table 6-3. 2620A/2625A A1 Main PCA Reference Fluke Stock Description Tot Qty Notes Designator IC,OP AMP,DUAL,LOW POWER,SOIC 867932 AR2,AR3 IC,OP AMP,QUAD,LOW POWER,SOIC 742569 C1,C3,C8, CAP,CER,0.1UF,+-10%,25V,X7R,1206 747287 C11,C19,C21- 747287 C25,C27-29, 747287 C33,C36-38, 747287 C40-42 747287 CAP,CER,0.033UF,+-10%,200V,X7R,1206...
Page 252 HYDRA Service Manual Table 6-3. 2620A/2625A A1 Main PCA (Cont) Reference Fluke Stock Description Tot Qty Notes Designator TRANSISTOR,SI,NPN,30V,200MW,SOT-23 820902 R1,R2,R11, RES,CERM,47K,+-5%,.125W,200PPM 746685 R12,R22 746685 R3,R4,R14, RES,CERM,10K,+-5%,.125W,200PPM 746610 R20,R21,R25, 746610 R42,R47,R64 746610 RES,CERM,1K,+-1%,.125W,100PPM,1206 783241 RES,CERM,3.32K,+-1%,.125W,100PPM 810788 R7,R16 RES,CERM,100K,+-5%,.125W,200PPM 740548 R8,R63 RES,CERM,270,+-5%,.125W,200PPM...
Page 253 List of Replaceable Parts Service Centers Table 6-3. 2620A/2625A A1 Main PCA (Cont) Reference Fluke Stock Description Tot Qty Notes Designator IC,CMOS,TRIPLE 3 INPUT NOR GATE,SOIC 867981 IC,CMOS,3-8 LINE DCDR W ENABLE,SOIC 783019 U12,U28 IC,CMOS,QUAD INPUT NAND GATE,SOIC 830703 IC,CMOS,OCTL LINE DRVR,SOIC...
Page 254: 2620A/2625A A1 Main Pca
HYDRA Service Manual 2620A-1601 s63f.eps Figure 6-3. 2620A/2625A A1 Main PCA 6-20...
Page 255: 2635A A1 Main Pca
List of Replaceable Parts Service Centers Table 6-4. 2635A A1 Main PCA Reference Fluke Stock Description Tot Qty Notes Designator BATTERY,LITHIUM,3.0V,0.560AH 821439 C1,C18 CAP,AL,220UF,+-20%,35V,SOLV PROOF 929708 CAP,CER,0.033UF,+-10%,200V,X7R,1206 602547 C3,C8 CAP,CER,27PF,+-10%,50V,C0G,1206 800508 C4,C5,C32, CAP,AL,1UF,+-20%,50V 782805 782805 CAP,AL,10UF,+-20%,63V,SOLV PROOOF 816843 CAP,AL,10000UF,+-20%,35V,SOLV PROOF...
Page 256 HYDRA Service Manual Table 6-4. 2635A A1 Main PCA (cont) Reference Fluke Stock Description Tot Qty Notes Designator MP101 PCB ASSY, MAIN SM 932017 HEADER,2 ROW,.050CTR,40 PIN 838573 CABLE ASSY,FLAT,10 CONDUCT,6.0” 714022 Q1-3,Q10 TRANSISTOR,SI,PNP,40V,300MW,SOT-23 742684 Q4-6 TRANSISTOR,SI,NPN,60V,350MW,SOT-23 742676 Q7,Q8 TRANSISTOR,SI,N-MOS,50W,D-PAK...
Page 257 List of Replaceable Parts Service Centers Table 6-4. 2635A A1 Main PCA (cont) Reference Fluke Stock Description Tot Qty Notes Designator R66,R67,R69, RES,CERM,47,+-5%,.0625W,200PPM 927707 R80,R82,R85, 927707 R87-91,R93- 927707 R97 R99-106, 927707 R108-118 927707 THERMISTOR,DISC,0.46,25 C 875240 VARISTOR,41.5V,+-9%,1.0MA,1206 914114 SWITCH,PUSHBUTTON,DPDT,PUSH-PUSH 836361...
Page 258 HYDRA Service Manual 2635A-1601 s64f.eps Figure 6-4. 2635A A1 Main PCA 6-24...
Page 259 MP321 WIRE,JUMPER,TEF,22AWG,WHT,.300 528257 R1,R10,R12 RES,CERM,10K,+-5%,.125W,200PPM 746610 RES,CERM,2.2M,+-5%,.125W,200PPM 811778 RES,CERM,1.2M,+-5%,.125W,200PPM 806240 RES,CERM,1K,+-5%,.125W,200PPM,1206 745992 IC,CMOS,4-BIT MPU,FLUKE 45-90002 820993 IC,CMOS,DUAL DIV BY 16 BIN CNTR,SOIC 837054 IC,CMOS,DUAL MONOSTB MULTIVBRTR,SOIC 806620 IC,CMOS,QUAD 2 IN NAND W/SCHMT,SOIC 837245 WIRE,JUMPER,TEF,22AWG,WHT,.300 528257 RES,CERM,SOIC,16 PIN,15 RES,10K,+-2% 836296 1. W1 IS NOT INSTALLED ON 2620A AND 2625A INSTRUMENTS.
Page 260 HYDRA Service Manual CKT 1 CKT 2 2620A-4002 s65f.eps Figure 6-5. A2 Display PCA 6-26...
Page 261 List of Replaceable Parts Service Centers Table 6-6. A3 A/D Converter PCA Reference Fluke Stock Description Tot Qty Notes Designator C1-3,C18,C21, CAP,CER,0.1UF,+-10%,25V,X7R,1206 747287 C22,C25,C29, 747287 747287 C4,C5 CAP,CER,15PF,+-10%,50V,C0G,1206 837393 C6,C7,C10 CAP,POLYPR,0.1UF,+-10%,160V 446781 C8,C9,C19 CAP,TA,10UF,+-20%,10V 714766 CAP,POLYPR,2200PF,+-5%,100V 854505 CAP,TA,2.2UF,+-10%,35V 697433 CAP,POLYPR,0.033UF,+-10%,63V...
Page 262 HYDRA Service Manual Table 6-6. A3 A/D Converter PCA (cont) Reference Fluke Stock Description Tot Qty Notes Designator R13,R43 RES,CF,270,+-5%,0.25W 810424 R14,R24-28 RES,CERM,47K,+-5%,.125W,200PPM 746685 RES,CERM,61.9K,+-1%,.125W,100PPM 821330 R16,R17,R20 RES,CERM,200K,+-5%,.125W,200PPM 746743 RES,CERM,16.9K,+-1%,.125W,100PPM 836635 RES,CERM,845,+-1%,.125W,100PPM 821322 RES,CERM,91K,+-5%,.125W,200PPM 811828 R29,R30 RES,CERM,22,+-5%,.125W,200PPM,1206 746230 R31,R32,R38 RES,CERM,100K,+-5%,.125W,200PPM...
Page 263 List of Replaceable Parts Service Centers K3, K5-K14 Relay Polarity Install with marked end as shown. Aromat or Nais Omron 2620A-1603 s66f.eps Figure 6-6. A3 A/D Converter PCA 6-29...
Page 264 HYDRA Service Manual Table 6-7. A4 Analog Input PCA Reference Fluke Stock Description Tot Qty Notes Designator CAP,CER,1000PF,+-5%,50V,C0G,1206 867408 RIVET,S-TUB,OVAL,AL,.087,.375 106473 CORE,BALUN,FERRITE,.136,.079,.093 106184 M1,M2 HEADER,1 ROW,.156CTR,15 PIN 414458 ANALOG INPUT CONNECTOR,PWB 873815 CONN,DIN41612,TYPE R,RT ANG,48 SCKT 867338 CONN,MICRO-RIBBON,REC,RT ANG,20 POS...
Page 265 List of Replaceable Parts Service Centers 2620A-1604 s67f.eps Figure 6-7. A4 Analog Input PCA 6-31...
Page 266 HYDRA Service Manual Table 6-8. A5 (Option -05) IEEE-488 Interface PCA Reference Fluke Stock Description Tot Qty Notes Designator C1-3 CAP,CER,0.1UF,+-10%,25V,X7R,1206 747287 HEADER,2 ROW,.100CTR,RT ANG,26 PIN 512590 HEADER,2 ROW,.100CTR,24 PIN 831834 RES,CERM,5.1K,+-5%,.125W,200PPM 746560 TERM,UNINSUL,WIRE FORM,TEST POINT 781237 IC,NMOS,GPIB CONTROLLER,PLCC 887190...
Page 267 List of Replaceable Parts Service Centers 2620A-1605 s68f.eps Figure 6-8. A5 IEEE-488 Interface PCA (Option -05) 6-33...
Page 268: 2625A A6 Memory Pca
HYDRA Service Manual Table 6-9. 2625A A6 Memory PCA Reference Fluke Stock Description Tot Qty Notes Designator C1-8 CAP,CER,0.1UF,+-10%,25V,X7R,1206 747287 HEADER,2 ROW,.100CTR,RT ANG,26 PIN 512590 TP1,TP2 TERM,UNINSUL,WIRE FORM,TEST POINT 781237 IC,CMOS,OCTAL D TRANSPARNT LATCH,SOIC 876235 IC,CMOS,QUAD 2 INPUT AND GATE,SOIC...
Page 269 List of Replaceable Parts Service Centers 2625A-1606 s69f.eps Figure 6-9. 2625A A6 Memory PCA 6-35...
Page 270 HYDRA Service Manual Table 6-10. 2635A A6 Memory Card I/F PCA Reference Fluke Stock Description Tot Qty Notes Designator C1-4,C6-8 CAP,CER,0.1UF,+-10%,25V,X7R,1206 747287 CAP,TA,47UF,+-20%,10V,7343 867580 CAP,TA,1UF,+-20%,35V,3528 866970 LED,RED,RIGHT ANGLE,3.0 MCD 927389 LED,YELLOW,RIGHT ANGLE,3 MCD 914242 CONN,MEMORY CARD,HEADER,RT ANG,68 PIN 914184 HEADER,2 ROW,.050CTR,RT ANG,40 PIN...
Page 271: 2635A A6 Memory Card I/F Pca
List of Replaceable Parts Service Centers 2635A-1606 s70f.eps Figure 6-10. 2635A A6 Memory Card I/F PCA 6-37...
Page 272 HYDRA Service Manual 6-38...
Page 273 Chapter 7 IEEE-488 Option -05 Title Page 7-1. Introduction ..................7-3 7-2. Theory of Operation ................7-3 7-3. Functional Block Description ............7-3 7-4. IEEE-488 PCA Detailed Circuit Description (2620A Only) ....7-3 7-5. Main PCA Connector............... 7-4 7-6. IEEE-488 Controller ................ 7-4 7-7.
Page 274 HYDRA Service Manual...
Page 275: Introduction
IEEE-488 Option -05 Introduction 7-1. Introduction The IEEE-488 Interface turns the Data Acquisition Unit 2620A into a fully programmable instrument for use with the IEEE Standard 488.1 (1987) interface bus (IEEE-488 bus). With the IEEE-488 Interface, the instrument can become part of an automated instrumentation system.
Page 276: Main Pca Connector
HYDRA Service Manual 7-5. Main PCA Connector The IEEE-488 PCA interfaces to the Main PCA through a 26-pin, right-angle connector (A5J1). This connector routes the 8-bit data bus, the lower three bits of the address bus, memory control, system clock, and address decode signals from the Main PCA to the IEEE-488 PCA.
Page 277: Ieee-488 Transceivers/Connector
IEEE-488 Option -05 General Maintenance 7-7. IEEE-488 Transceivers/Connector The IEEE-488 Transceivers (A5U2 and A5U3) are octal transceivers that are specifically designed to exhibit the proper electrical drive characteristics to meet the IEEE-488 standard. These transceivers are configured to match the control signals available on the IEEE-488 Controller.
Page 278 HYDRA Service Manual MOUNTING SCREW (2) GROUNDING SCREW CASE REAR BEZEL REMOVE PLASTIC PLUG FROM CASE CHASSIS IEEE-488 PCA RETAINING SCREWS 6-32, 1 / 4 INCH PANHEAD SCREW 24-LINE RIBBON CABLE ASSEMBLY s53f.eps Figure 7-1. Installation...
Page 279: Installing The Ieee-488 Option
Use the following performance test program to verify operation of the IEEE-488 Interface. This program is written for use with the Fluke 1722A Instrument Controller and its interpreted BASIC language. The program may be adapted to the language of any IEEE-488 controller.
Page 280: Troubleshooting
HYDRA Service Manual 7-12. Troubleshooting 7-13. Power-Up Problems The following discussion identifies probable fault areas if the installation of an IEEE- 488 Option causes power-up failure for the instrument. The problem is probably a short on A5J1; the Microprocessor on the Main Assembly is prevented from accessing ROM and RAM correctly.
Page 281: Failure To Receive Multiple Character Commands
IEEE-488 Option -05 List of Replaceable Parts 7-18. Failure to Receive Multiple Character Commands Monitor the IRQ2* interrupt signal from A5U1-10 during attempts to communicate with the instrument. Each byte received with the ATN signal (A5U1-31) high should cause the interrupt signal to go low. Verify that the signal arrives at A5J1 properly. An interrupt not detected by A1U4 will remain low indefinitely.
Page 282 HYDRA Service Manual 7-10...
Page 283: Figure Title Page
Chapter 8 Schematic Diagrams Figure Title Page 8-1. A1 Main PCA (2620A/2625A)................8-3 8-2. A1 Main PCA (2635A)..................8-8 8-3. A2 Display PCA ....................8-14 8-4. A3 A/D Converter PCA..................8-16 8-5. A4 Analog Input PCA....................8-20 8-6. A5 (Option -05) IEEE-488 Interface PCA.............8-22 8-7. A6 Memory PCA (2625A)..................8-24 8-8.
Page 284 HYDRA Service Manual...
Page 285: Schematic Diagrams
Schematic Diagrams 2620A-1601 s88f.eps Figure 8-1. A1 Main PCA (2620A/2625A)
Page 286: Interconnect Diagram
Schematic Diagrams NOTES: UNLESS OTHERWISE SPECIFIED ALL RESISTORS ARE 1/4W 5%. ALL CAPACITOR VALUES ARE IN MICROFARADS. POWER SUPPLY PIN NUMBERS D E S V C C G N D V D D R C O M D O _ G N D A01AR1 INTERCONNECT DIAGRAM A01AR2...
Page 287 Schematic Diagrams D C H D C H S H 4 R A W S U P P L Y M B R D 3 6 0 R X E 0 6 5 S H 4 C 5 9 PFAIL* 180PF S H 3 1/8A SB...
Page 288 Schematic Diagrams 2620A-1001 (3 of 4) s73f.eps Figure 8-1. A1 Main PCA (2620A/2625A) (cont)
Page 289 Schematic Diagrams R 5 8 4 7 K 4 7 0 CR15 2 2 K B A W 5 6 C 5 4 LM358DT 180PF R 4 9 4 7 K 4 7 0 350K 2 2 K C 4 3 TP19 180PF R 5 7...
Page 290: A1 Main Pca (2635A)
Schematic Diagrams POWER SUPPLY PIN NUMBERS VDDR (5.0V dc) (+5V dc) (5.6V dc) A1U1 3, 13, 23, 18, 28, 29, 34, 39, 62, 44, 50, 72, 74, 57, 67, 83, 99, 73, 84, 112, 131 102, 107, 116, 126 A1U2 2, 5, 7, 9, 12 A1U3...
Page 291 Schematic Diagrams C R 1 M B R D 3 6 0 2 6 2 0 A - 6 5 0 1 1/8A SB R X E 0 6 5 C R 3 C 5 9 180PF SHEET 5 1 N 5 3 9 7 D C H D C L SHEET 4...
Page 292 Schematic Diagrams 2635A-1001 (2 of 5) s76f.eps Figure 8-2. A1 Main PCA (2635A) (cont) 8-10...
Page 293 Schematic Diagrams 2635A-1001 (3 of 5) s77f.eps Figure 8-2. A1 Main PCA (2635A) (cont) 8-11...
Page 294 Schematic Diagrams S W R 1 S W R 2 S W R 6 S W R 5 S W R 3 S W R 4 A<23..1> R D U * V C C R 8 7 O C L K R 4 2 R 7 0 R 6 4...
Page 295 Schematic Diagrams TOTI* EXTERNAL TRIGGER AND TOTALIZER INPUTS V C C V C C R 5 8 DI<7..0> R 5 7 L M 3 2 4 D 4 7 K 4 7 0 C 5 4 4 7 K C R 1 5 1/4W 180PF 2 2 K...
Page 296: A2 Display Pca
Schematic Diagrams CKT 1 CKT 2 2620A-4002 s90f.eps Figure 8-3. A2 Display PCA 8-14...
Page 297: A2 Display Pca
Schematic Diagrams POWER SUPPLY PIN NUMBERS REF DES VLOAD (5.1V dc) (5.0V dc) (-28.5 to -30.0V dc) A2U1 A2U4 2, 8 A2U5 10, 16 A2U6 7, 9, 10 A2Z1 2620A-1002 s80c.eps Figure 8-3. A2 Display PCA (cont) 8-15...
Page 298: A3 A/D Converter Pca
Schematic Diagrams K3, K5-K14 Relay Polarity Install with marked end as shown. Aromat or Nais Omron 2620A-1603 s91c.eps Figure 8-4. A3 A/D Converter PCA 8-16...
Page 299: A3 A/D Converter Pca
Schematic Diagrams POWER SUPPLY PIN NUMBERS VDDR RCOM ANALOG_GND (5.3V dc) (5.4V dc) (5.6V dc) A3U1 10, 11, 12 A3U2 1, 16 6, 9 A3U3 1, 10, 11, 2, 7 12, 13, 14 A3U4 A3U5 A3U6 1, 3, 4 A3U7 A3U8 4, 25, 27, 38 A3U9...
Page 300 Schematic Diagrams 2620A-1003 (2 of 3) s82c.eps Figure 8-4. A3 A/D Converter PCA (cont) 8-18...
Page 301 Schematic Diagrams 2620A-1003 (3 of 3) s83c.eps Figure 8-4. A3 A/D Converter PCA (cont) 8-19...
Page 302: A4 Analog Input Pca
Schematic Diagrams 2620A-1604 s92f.eps Figure 8-5. A4 Analog Input PCA 8-20...
Page 303: A4 Analog Input Pca
Schematic Diagrams 910V 910V CH1_HI CH1_LO CH1_HI NOTES: CH1_LO CH2_HI CH2_HI UNLESS OTHERWISE SPECIFIED. C H 2 _ L O C H 2 _ L O CH3_HI CH3_HI ALL CAPACITOR VALUES ARE IN MICROFARADS. C H 3 _ L O C H 3 _ L O CH4_HI CH4_HI...
Page 304 Schematic Diagrams 2620A-1605 s93f.eps Figure 8-6. A5 IEEE-488 Interface PCA (2620A Only) 8-22...
Page 305 Schematic Diagrams REF DES POWER SUPPLY PIN NUMBERS (5.1V dc) A5U1 3, 44 A5U2 10,11 A5U3 A5U4 1,2,4,5,7,9,10 2620A-1005 s85c.eps Figure 8-6. A5 IEEE-488 Interface PCA (2620A Only) (cont) 8-23...
Page 306: A6 Memory Pca (2625A)
Schematic Diagrams 2625A-1606 s94f.eps Figure 8-7. A6 Memory PCA (2625A) 8-24...
Page 307 Schematic Diagrams REF DES POWER SUPPLY PIN NUMBERS (5.1V dc) A6U1 1, 10 A6U2 7, 12, 13 A6U3 A6U4 3, 12 A6U5 A6U6 A6U7 A6U8 5, 8 2625A-1006 s86c.eps Figure 8-7. A6 Memory PCA (2625A) (cont) 8-25...
Page 308: A6 Memory Card I/F Pca (2635A)
Schematic Diagrams POWER SUPPLY PIN NUMBERS Reference Designations Lasted Used Not Used (5.0V dc) A6U1 1, 11, 12, 13, 14, 15, 17,18 16, 27, 46, 60, 76, 106, 107, 19, 20, 21, 31, 41, 51, 61, 113, 116, 120 71, 81, 91, 101, 105, 111, A6U2 A6U3 2, 4, 6, 7, 8, 10...
Page 309 Schematic Diagrams V C C SI9405DY C V P P VPP1 V P P 2 C V C C V C C R 1 7 V C C 4 7 K 4 7 K 3 5 V 2 5 V 1 0 K 3 6 0 D S 2...
Page 310 Schematic Diagrams 8-28...

Fluke HYDRA 2620A Manual

Table of Contents

List of Figures

Theory of Operation (2620A/2625A)

A Theory of Operation (2635A)

General Maintenance

Performance Testing and Calibration

Diagnostic Testing and Troubleshooting (2620A/2625A)

A Diagnostic Testing and Troubleshooting (2635A)

Quick Links

Chapters

Troubleshooting

Related Manuals for Fluke HYDRA 2620A

Summary of Contents for Fluke HYDRA 2620A