Related Manuals for Polar Instruments PFL720
Summary of Contents for Polar Instruments PFL720
- Page 1 PFL720 Polar Instruments Ltd. Garenne Park SERVICE St. Sampson Guernsey MANUAL Channel Islands http://www.polar.co.uk Fax: +44 (0)1481 252476 Email: mail@polar.co.uk MAN 168–9803...
- Page 2 Copyright Polar Instruments Ltd. 1997 Microsoft and MS-DOS are registered trademarks of Microsoft Corporation IBM is the registered trademark of International Business Machines Corporation.
- Page 3 PFL720 FAULT LOCATOR SERVICE MANUAL POLAR INSTRUMENTS LTD. HARDWARE WARRANTY Product Warranty. Product hardware is warranted to be free from defects in material and workmanship during the Warranty Period (as defined below). Product hardware is warranted to conform substantially to Polar’s then current (as of the date of Polar’s product shipment) published user documentation during the Warranty Period.
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Page 5: Declarations
DECLARATIONS European Community Directive Conformance Statement Refer to the Operator Manual to determine conformance with European Community Directives. -
Page 6: Safety
PFL720 SERVICE MANUAL SAFETY WARNING The service instructions contained in this manual are for use by qualified electronic service personnel only. WARNING The LIVE and NEUTRAL lines on later units are BOTH fused. When the unit is connected to its supply, the opening of covers or removal of panels is likely to expose dangerous voltages. -
Page 7: Operation
The unit is designed for use indoors in an electrical workshop environment at a stable work station comprising a bench or similar work surface. Use only the accessories (e.g. test probes and cables) provided by Polar Instruments. The instrument must be maintained and repaired by a skilled electronics technician in accordance with the manufacturer’s instructions. -
Page 8: Specifications
PFL720 SERVICE MANUAL SPECIFICATIONS 500µA Test Ranges Junction Logic 150mA High 90Hz Test Frequencies Low 500Hz Medium 2kHz High 0 – ±5V variable level Pulse Generator DC, Pulse mode 1, Pulse width variable Pulse mode 2 1 – 99% Tolerance adjustment... -
Page 9: Channel A And B Protection Fuses
7.0kg (15.4 lb.) SYMBOLS REFER TO MANUAL These sockets are for connecting only Polar Instruments probes and connectors for use as described in the Operator Manual. To prevent damage to this product and to ensure its safe use observe the specifications given in this manual when connecting to terminals marked with this symbol. -
Page 10: Table Of Contents
PFL720 SERVICE MANUAL CONTENTS DECLARATIONS................................ i European Community Directive Conformance Statement ..................i SAFETY..................................ii WARNING ................................ii GROUNDING ................................ii POWER SUPPLY ..............................ii OPERATION................................iii CAUTION ................................iii Electrical Isolation ............................iii Static Sensitive Devices............................iii SPECIFICATIONS..............................iv ENVIRONMENTAL OPERATING CONDITIONS .................... -
Page 11: Contents
CONTENTS WAVEFORM GENERATION AND DRIVE CIRCUITS ................3-3 Waveform generators/buffers ........................3-3 Digital to analog converters ...........................3-3 DRIVE CIRCUITS ............................3-4 INPUT AMPLIFIER............................3-4 System OK LED ............................3-4 A to D CONVERTER............................3-5 Analog to digital conversion ..........................3-5 Signal input selection.............................3-5 PULSER................................3-5 Pulse generator width control ........................3-5 Amplitude and polarity control ........................3-5 POWER SUPPLIES............................3-6 High voltage supply ............................3-6... -
Page 13: Section 1 - Performance Check
SECTION 1 – PERFORMANCE CHECK MAINTENANCE AND CALIBRATION OF INSTRUMENTS For most of Polar Instruments’ products there are two maintenance procedures — the Performance Check and the Calibration. Some instruments may have a single (combined) procedure. Performance Check The Performance Check (or Checkout Procedure) is used to verify the basic functions of the instrument. -
Page 14: Performance Check
If communication fails check that the correct cable is in use and that it is connected to the selected serial port on the PC. If a fault in the PFL720 is detected such as a fuse failure this should be corrected and the diagnostic repeated until all tests pass before proceeding. - Page 15 PERFORMANCE CHECK 6. Select LOW range and LOW frequency. Set PULSER MODE to DC Pos. Set the LEVEL to 100% and WIDTH to 50%. Using a DVM measure the voltage between COM and a pulser socket, the reading should indicate 5V ± 0.5V 7.
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Page 17: Section 2 - Calibration
SECTION 2 – CALIBRATION CALIBRATION PROCEDURE WARNING: Hazardous voltages are exposed on the PCB when the cover is removed. This procedure should only be performed by a technically qualified person aware of the hazards and taking all reasonable care. Equipment required Accurate (0.5% or better at 10V DC) DVM Procedure 1. -
Page 19: Section 3 - Circuit Description
SECTION 3 – CIRCUIT DESCRIPTION THE MICROPROCESSOR KERNEL Refer to the PROCESSOR schematics System processor The system is based on an 8086 running in "min" mode at 8MHz. The clock oscillator is U21D and the frequency is set by X2 at 8MHz. The signal is buffered by U21E and U21C and then applied to the processor and the waveform generator. -
Page 20: The I/O System
PFL720 SERVICE MANUAL THE I/O SYSTEM Refer to the SYSTEM CONTROL schematics The input/output system All I/O in the system is memory-mapped; the processor’s I/O capabilities are not used. The control output signals are latched into 74HC374 ICs connected in pairs across the 16 bits of the data bus. -
Page 21: Waveform Generation And Drive Circuits
CIRCUIT DESCRIPTION WAVEFORM GENERATION AND DRIVE CIRCUITS Refer to the SINE GENERATOR schematic Waveform generators/buffers The waveforms required by the instrument are all generated from data stored in the two ROMs U38 and U39. 8MHz from the system clock oscillator is divided down by U50, a simple ripple counter, to provide a range of clock signals used throughout the instrument. -
Page 22: Drive Circuits
PFL720 SERVICE MANUAL DRIVE CIRCUITS Refer to the DRIVE CIRCUITS schematics The drive for the A (B) LOW voltage ranges is provided by power op-amp U52 (U53) whose output is protected by fuse F1 (F2) and voltage limiting zener diodes. The short circuit current is limited by the range resistors and the output is connected to the range selection relays. -
Page 23: A To D Converter
CIRCUIT DESCRIPTION A to D CONVERTER Refer to A to D CONVERTER schematic Analog to digital conversion U58 is a combined A to D and DAC sharing the 8-bit data bus interface. The DAC output from pin 2 is passed through demultiplexor U59 to one of the analogue stores, capacitors C36 – C44 and high input impedance op-amp buffers U47, U56 and U62. -
Page 24: Power Supplies
PFL720 SERVICE MANUAL POWER SUPPLIES Refer to the POWER schematics High voltage supply Power transformer T1 incorporates 3 secondaries providing one pre-regulation supply of about 210V, and two of 20V. The high voltage supply is regulated down to 180V by U69. R139 and D19 maintain the differential across the device to within safe limits. -
Page 25: Section 4 - Dismantling Instructions
SECTION 4 – DISMANTLING INSTRUCTIONS WARNING Service of this instrument should only be performed by skilled electronics service personnel. There are hazardous voltages inside the instrument when connected to its power supply. REMOVE THE POWER CORD before touching any part of the line input circuit. Note that high voltages may continue to be present for 2 minutes after power is removed until internal capacitors discharge. -
Page 27: Section 5 - Line Voltage And Fuse Changing
SECTION 5 – LINE VOLTAGE AND FUSE CHANGING WARNING: There are hazardous voltages inside the instrument when connected to its power supply. REMOVE THE POWER CORD before touching any part of the line input circuit. Note that high voltages may continue to be present for 2 minutes after power is removed until internal capacitors discharge. -
Page 28: Input Protection Fuses
PFL720 SERVICE MANUAL Input Protection Fuses Channels A and B are protected by fast blow fuses. If the probes are connected to a powered board, or to a large, charged capacitor, these fuses open to minimise damage to the instrument. -
Page 29: Section 6 - Fault Diagnosis
SECTION 6 – FAULT DIAGNOSIS WARNING: Hazardous voltages are exposed on the PCB when the cover is removed. These procedures should only be performed by a technically qualified person aware of the hazards and taking all reasonable care. SYSTEM DIAGNOSTICS If the “System OK”... -
Page 31: Section 7 - Maintenance And Cleaning
If it becomes necessary to repair the instrument, in the first instance contact the Polar Instruments distributor in your country. In case of difficulty contact Polar Instruments Ltd. at the address at the front of this manual. Do not send the instrument until shipping instructions have been received from the... -
Page 33: Section 8 - Replacement Parts
Note: Parts marked with an asterisk (*) have been subject to modification in later instruments. Safety critical parts (listed in bold type) must be replaced with parts obtained from Polar Instruments Ltd or your Polar Instruments distributor to ensure continued safe operation. -
Page 34: Main Board Components
PFL720 SERVICE MANUAL MAIN BOARD COMPONENTS Part Nº Description Circuit Reference CEA103 10uF Electrolytic C13, C35, C47, C49, C50, C52, C105, C106, C114 CEA105 220uF C25, C28, C30, C902, C903 CEA113 22uF C1, C2, C3, C4, C5, C6, C7, C10 CEA118 3.3uF 250V... - Page 35 REPLACEMENT PARTS ICA192 74HC374 U1, U2, U3, U4, U9, U16, U40, U44, U45, U66, U107, U902, U913 ICA194 6264 U34, U35 ICA214 LM7812 U108 ICA227 8253 / 71054 ICA236 ULN2003 ICA240 4053 U51, U909 ICA241 4052 ICA243 4051 U59, U60, U63 ICA244 74HC153 U48, U912...
- Page 36 PFL720 SERVICE MANUAL *MQX337 ¼" Stereo Jack MSH104 M3 Solder Tag MSH108 Resistor Bracket R49, R82 MWPD919 Volts Warning Label QNN303 MPSA42 Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, QNN304 2N3904 Q9, Q20 QPP102 2N3906 RCC107 47R 1W R910, R913...
- Page 37 REPLACEMENT PARTS RCT33K 1/4W R123 RCT390K 390K 1/4W R131 RCT47K 1/4W R100, R101, R102, R104, R105, R106, R107, R108, R902, R903 RCT49K9 49K9 1/4W R116, R118 RCT4K02 4K02 1/4W R28, R29, R30, R31 RCT4K99 4K99 1/4W R23, R27, R32, R33, R35, R36, R39, R43 R44, R45 *RCT44K2 44K2...
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Page 38: Mechanical Components
PFL720 SERVICE MANUAL MECHANICAL COMPONENTS Part Nº Description Circuit Reference ICA248 LM7815 U104, U105 ICA250 TL783 *IND110 Ferrite Bead *MAA129 Fuse holder, Panel MCA149 Side Moulding MCA165 Enclosure MCA154 Front Moulding MKB153 Round Button MMP171 Rt angle Bracket MMP172 Spacer 5mm OD by 8mm... - Page 39 REPLACEMENT PARTS LED117 Green LED *LED115 Red LED *LED120 Bi-Color LED MPCD941 LED PCB MPP201 Spacer WMA108 Link 0.5" WMA268 LED Cable...
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Page 41: Section 9 - Schematic Diagrams
SECTION 9 – SCHEMATIC DIAGRAMS Note: diagrams refer to “PFL760” but also apply to the PFL720. - Page 42 This page is intentionally blank.
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