Agilent Technologies 4338B Service Manual
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Agilent Technologies 4338B Service Manual

Milliohmmeter
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Agilent 4338B Milliohmmeter
Service Manual
This manual applies directly to instruments with serial number pre x JP1KD.
For additional important information about serial numbers, read
\Instruments Covered by This Manual" in Chapter 1 of this manual.

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  • Page 1 Agilent 4338B Milliohmmeter Service Manual This manual applies directly to instruments with serial number pre x JP1KD. For additional important information about serial numbers, read \Instruments Covered by This Manual" in Chapter 1 of this manual.
  • Page 2 This document contains proprietary information that is protected by copyright. All rights are reserved. No part of this document may be photocopied, reproduced, or translated to another language without the prior written consent of the Agilent Technologies. Agilent Technologies Japan, Ltd.
  • Page 3 Manual Printing History August 1996 : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : First Edition (part number: 04338-90033) June 2000 : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : Second Edition (part number: 04338-90033) March 2001 : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : Third Edition (part number: 04338-90033)
  • Page 4 WARNINGS elsewhere in this manual may impair the protection provided by the equipment. In addition it violates safety standards of design, manufacture, and intended use of the instrument. The Agilent Technologies assumes no liability for the customer's failure to comply with these requirements. Note 4338B complies with INSTALLATION CATEGORY II and POLLUTION DEGREE 2 in IEC1010-1.
  • Page 5 Agilent Technologies. Buyer shall prepay shipping charges to Agilent Technologies and Agilent Technologies shall pay shipping charges to return the product to Buyer. However, Buyer shall pay all shipping charges, duties, and taxes for products returned to Agilent Technologies from another country.
  • Page 6 Exclusive Remedies The remedies provided herein are buyer's sole and exclusive remedies. Agilent Technologies shall not be liable for any direct, indirect, special, incidental, or consequential damages, whether based on contract, tort, or any other legal theory. Assistance Product maintenance agreements and other customer assistance agreements are available for Agilent Technologies products.
  • Page 7 Safety Symbols General de nitions of safety symbols used on equipment or in manuals are listed below. Instruction manual symbol: the product is marked with this symbol when it is necessary for the user to refer to the instruction manual. Alternating current. Direct current.
  • Page 8 4338Bs manufactured before the printing date of the manual. Appendix B Default Jumper and Switch Settings Appendix B describes the settings of the jumpers and switches on the 4338B A2 CPU Board Assembly. The information is required when the A2 assembly is replaced.

  • Page 9: Table Of Contents

    Contents Introduction ....... . . Instruments Covered by This Manual ..... Required Equipment .
  • Page 10 Introduction ....... . . Safety Considerations ......Required Equipment .
  • Page 11 4-1. Voltage Current Ratio Measurement Principle ....4-2. 4338B Overall Block Diagram ......

  • Page 13: Introduction

    Complimentary copies of the supplement are available from Agilent Technologies. If the serial pre x or number of an instrument is lower than that on the title page of this manual, see Appendix A, Manual Changes . For information concerning, a serial number pre x that is not listed on the title page or in the Manual Change supplement, contact the nearest Agilent Technologies oce.

  • Page 14: Required Equipment

    Required Equipment Table 1-1 lists the required equipment for adjusting and troubleshooting the 4338B. Table 1-2 lists the required language extensions to be used with the adjustment program. Multimeter DC V Accuracy: < 1% 3458A Standard Resistors No Substitute 42030A...

  • Page 15: Introduction

    Adjustment Introduction This chapter describes the adjustment required to ensure the 4338B is within its published speci cations after it has been repaired. The adjustment should be performed along with periodic maintenance to keep the 4338B in optimum operating condition. If proper performance cannot be achieved after adjustment, proceed to Chapter 4.

  • Page 16: Adjustment Tools

    EEPROM Write Protect Switch There are no EEPROM write protect switches in the 4338B. Related Adjustment There is only one adjustment for the 4338B. Table 2-1 lists the adjustment that must be performed if an assembly has been replaced. A1 Main Board Assy...

  • Page 17: Adjustment Program

    Adjustment Program The adjustment program listed in Table 1-1 is required for the adjustment. Using the program, the computer controls the 4338B to obtain the adjustment data, and stores the data in the 4338B internal EEPROM, A2U1. The adjustment program runs on the computer listed in Table 1-1. The program should be installed into your computer according to the procedure described in \Program Installation".

  • Page 18: Program Installation

    Note If the adjustment being performed follows right after EEPROM replacement, change switch A2SW1-1 to \CLOSE", so that the 4338B will ignore the self test errors at power-on. (Return the switch to \OPEN" when the adjustment has been completed.) Refer to Figure B-1 for the switch location.

  • Page 19: Adjustment Procedure References

    This setup obtains the range resistor adjustment data and the process ampli er attenuator adjustment data. Perform the following steps as the program instructs. 1. Connect the speci ed termination or standard resistor directly to the 4338B UNKNOWN Connectors. 2. Repeat step 1 as instructed.

  • Page 21: Introduction

    This chapter provides the 4338B replaceable parts lists, and the step by step disassembly procedures for the major assemblies. Table 3-1 to Table 3-7 describe all the 4338B replaceable parts. The gure section of Table 3-7 also shows the cable connections.

  • Page 22: Replacing The A2 Cpu Board Assembly

    ROM and EEPROM are not defective. The ROM transfer reduces parts cost for the repair, and the EEPROM transfer saves time from readjusting the 4338B. For this purpose, the A2 assembly can only be ordered without the ROM.
  • Page 23 04263-66505 A5 AC Inlet Board Assembly 04263-60004 Transformer Assembly 04263-80901 DC-DC Converter Unit 04263-66532 A2 CPU Board Assembly w/o ROM 04263-00604 Case Shield 0515-1550 Screw M3 04338-66504 A4 Keyboard Assembly 04338-25151 Rubber Key 0515-1550 Screw M3 04263-61010 LCD Assembly 04263-25003 Filter Transparent 0515-1550 Screw M3...
  • Page 24 2110-1123 A2F1, Fuse SMT 2A 1818-5146 A2U1, EEPROM 04338-85031 A2U11, ROM Rev. 1.00 A1C500 0180-4334 Capacitor, 22000  F (for power supply) A1C501 0180-4334 Capacitor, 22000  F (for power supply) A5SW1 3101-3171 Line Switch A5VR1 0837-0237 Varistor A5VR2 0837-0237 Varistor Assembly Replacement...

  • Page 25: Replaceable Mechanical Parts List

    Replaceable Mechanical Parts List The replaceable mechanical parts are listed in Table 3-4 to Table 3-7. Reference Agilent Part Qty. Description Designation Number 04263-04004 Cover 5041-9167 Foot 1460-1345 Tilt Stand 04338-65020 Front Panel Assembly 5041-9170 Trim Side 0515-0914 Screw M3 (Hidden) 04263-40001 Front Bezel 04263-00605...
  • Page 26 04263-61615 GPIB Connector with atcable 2110-0565 Fuse Holder 2110-0202 Fuse 0.25 A, Slow Blow (230V) 2110-0201 Fuse 0.5 A, Slow Blow (115V) 0515-1551 Screw M3 04338-00102 Chassis 2190-0054 Washer 2950-0054 Includes two sets of screw, washer , and nut. Assembly Replacement...
  • Page 27 0515-2079 Screw M4 (on the Chassis) 04263-24001 Nut Rod (for Transformer) 2190-0586 Washer Spring M4 04263-00607 Plate Shield 04263-24002 Nut Rod (for DC-DC Conv.) 2190-0584 Washer Spring M3 0515-1550 Screw M3 (for A1 and A2) 04339-24006 Stando (Hidden, for A1) 5040-3347 Plate (Hidden, Chassis Reverse side) 0460-0616...
  • Page 28 04263-61608 Wire Assy (V Selector) 04263-61602 Cable Assembly, \A"-\A" 04339-25004 Core Holder 0515-1550 Screw M3 04263-61604 Cable Assembly, \B"-\B" 04339-25004 Core Holder 0515-1550 Screw M3 04263-61605 Cable Assembly, \C"-\C" 04339-25004 Core Holder 0515-1550 Screw M3 04338-61603 Cable Assembly 04339-61614 Wire Assy (Binding Post) Assembly Replacement...

  • Page 29: Disassembly Procedures

    The 4338B mechanical components are secured using metric threaded fasteners. Many fasteners in the 4338B may appear to be Phillips type, but they are in fact, Pozidrive type. To avoid damaging them, use only pozidrive screwdrivers to remove or tighten pozidrive type fasteners.

  • Page 30: A1 Main Board Removal

    A1 Main Board Removal Removal Procedure 1. Remove the A2 CPU Board Assembly referring to \A2 CPU Board Assembly Removal". 2. Disconnect the following cable assemblies and wire assemblies from the A1 assembly. a. The three cable assemblies marked \A", \B", and \C" which are connected to the UNKNOWN connectors on the Front Panel b.

  • Page 31: Keyboard Assembly Removal

    6. Remove the A5 assembly from the chassis. Keyboard Assembly Removal Removal Procedure 1. Remove the cover referring to \Cover Removal". 2. Disconnect the two atcable assemblies and the wire assembly from the front side of the A2 assembly. 3. Remove the two at head screws that secure the front panel from the bottom. 4.
  • Page 32 8. Remove the core holder which holds the cable assembly which is connected to the BNC connector being replaced, by unscrewing the screw secures the holder from the front side. 9. Disconnect the cable from the BNC connector housing being replaced, by unscrewing the nut which fastens, from the back of the front panel, the cable to the BNC connector.

  • Page 33: Introduction

    Troubleshooting Introduction This chapter provides assembly level troubleshooting information for the 4338B. The information includes theory of operation, and troubleshooting. Safety Considerations This chapter contains WARNINGs and CAUTIONs that must be followed for your protection and to avoid damaging the equipment.

  • Page 34: After Service Product Safety Checks

    0.1 . Flex the power cord while making this measurement to determine if any intermittent discontinuities exist. 3. Unplug the 4338B's power plug from the power source. Set the line switch to ON. Tie the line and neutral pins of the power connector together and check the resistance between them and enclosure.

  • Page 35: Theory Of Operation

    Theory of Operation This section describes the general overall operation of the 4338B and the operation of each assembly. Overall Measurement Theory The 4338B measures the resistance of the Device Under Test (DUT) by measuring vector voltage to current ratio. A vector is a value which consists of a magnitude and a phase. The DUT resistance is the real part of vector impedance which is determined by the vector ratio between the voltage across the DUT and the current owing through the DUT.

  • Page 36: Overall Block Diagram

    Overall Block Diagram Figure 4-2 shows the overall block diagram of the 4338B. The signal source section applies measurement signal to the range resistor and DUT in series. The current sense ampli er measures the voltage across the range resistor, which is proportional to the current owing through the DUT.

  • Page 37: Analog Section

    Analog Section Figure 4-3 shows the analog section block diagram. The 4338B analog section can be divided in six sections, the signal source, range resistor, current sense ampli er, voltage sense ampli er, process ampli er, and dry circuit loop. The signal source generates a 1 kHz signal of which level is set from the keyboard or by GPIB commands.

  • Page 38: Signal Source Section

    Signal Source Section The signal source generates a 1 kHz signal of which output current is selected from among 1  A, 10  A, 100  A, 1 mA, and 10 mA (in rms). The output current is determined by the attenuator and the following ampli er. The dry circuit loop controls the attenuation, so that the voltage across the DUT is not more than 20 mV.

  • Page 39: Range Resistor And Current Sense Ampli Er Sections

    Range Resistor and Current Sense Ampli er Sections These sections measure current owing through the DUT. Figure 4-5 shows this section's block diagram. The range resistor converts the current to a proportional voltage which is measured. The range resistor consists of four resistors, which are switched according to the signal source output level.

  • Page 40: Voltage Sense Ampli Er And Process Ampli Er Sections

    Voltage Sense Ampli er and Process Ampli er Sections These sections measure the voltage across the DUT and processes the outputs from the voltage sense ampli er and the current sense ampli er. Figure 4-6 shows this section's block diagram. The voltage sense ampli er, which is a di erential ampli er, measures the vector voltage across the DUT via the High-Potential (H ) and Low-Potential (L ) connectors.

  • Page 41: Digital Section

    A1 assembly and receive the measurement data. The GPIB interface on the A2 Assembly allows the 4338B communicate with a controller. A handler interface on the A1 Assembly allows the 4338B communicate with an external handler.

  • Page 42: Power Supply Section

    Varistor, VR1 protects the circuit from surge voltage on the line power. VR2 blows fuse F1 if the 4338B is turned on with the wrong line voltage setting selection, for example, 115V selection when using a 230V line.

  • Page 43: Troubleshooting

    Troubleshooting Figure 4-9 shows the overall troubleshooting owchart to nd the defect assembly. Follow the owchart when troubleshooting. Refer to the \Check Procedure References" for the detailed procedure to check each item. Refer to Chapter 3 for assembly replacement. Note Because of each assembly's high SMD (surface mount device) ratio, the repair should be done by assembly replacement.
  • Page 44 4-12 T roubleshooting...

  • Page 45: Check Procedure References

    Check 1, DC-DC Converter Output Voltage 1. Remove the cover referring to \Cover Removal" in Chapter 3. 2. Turn on the 4338B. 3. Using a multimeter, check to see if the voltages between the test pads and the ground (TP500), shown in Table 4-1, on A1 Main Board Assembly are in the ranges shown.

  • Page 46: Check 2, Lcd Displays Anything

    Check 2, LCD Displays Anything? 1. Turn o the 4338B. 2. Turn on the 4338B while watching the LCD. 3. Check for a beep sound for a moment and if you see anything is displayed on the LCD. 4. If beep sounds and LCD displays something, proceed to \Check 3, LCD Operates Correctly?", otherwise proceed to \Check 6, CPU Power LED Lights?".

  • Page 47: Check 7, Any Error Code On Led

    Check 7, Any Error Code on LED? 1. Turn o the 4338B. 2. Turn on the 4338B while watching LEDs on the A2 CPU Board Assembly. 3. Check if the LEDs light in the sequence shown in Figure 4-11. 4. If LEDs light as the sequence, replace the LCD Assembly, otherwise (possibly, \HALT"...

  • Page 48: Check 8, Cpu Fuse High Lead Voltage

    Assembly. Check 9, Fuse and Line Switch 1. Check that the fuse on the 4338B rear panel is not blown. 2. Check that the line switch on the A5 AC Inlet Board Assembly is not defective. 3. If passed, proceed to \Check 10, DC-DC Converter Input Voltage", otherwise replace the defective line switch or blown fuse.

  • Page 49: Check 10, Dc-Dc Converter Input Voltage

    Check 10, DC-DC Converter Input Voltage 1. Turn on the 4338B. 2. Using a multimeter, check if the voltage between \DC OUT" test pad and TP500 (DC-DC Converter input voltage) is between 12 V and 15 Vdc. Refer to Figure 4-13 for test pad and pin locations.

  • Page 50: Check 11, Dc-Dc Converter Open Output Voltages

    Check 11, DC-DC Converter Open Output Voltages 1. Turn o the 4338B. 2. Disconnect the DC-DC Converter Output Cable shown in Figure 4-14 from connector \J504" on the A1 Main Board Assembly. 3. Turn the 4338B on. 4. Using the multimeter, check if the DC-DC Converter open output voltages on the output connector pins shown in Figure 4-14 are in the ranges shown in Table 4-2.

  • Page 51: Check 12, Transformer Secondary Voltage

    Check 12, Transformer Secondary Voltage 1. Turn o the 4338B. 2. Disconnect the transformer secondary connector from connector \J501" on the A1 Main Board Assembly. Refer to Figure 4-15 for the connector location. 3. Turn the 4338B on. 4. Using a multimeter, check if the transformer secondary voltage is between +13 V and + 17Vac.

  • Page 53: Introduction

    Manual Changes To adapt this manual to your 4338B, refer to Table A-1, and make all of the manual changes listed opposite your instrument's serial number. Instruments manufactured after the printing of this manual may be di erent from those documented in this manual.

  • Page 55: Introduction

    Default Jumper and Switch Settings Introduction This appendix describes the setting of the jumpers and switches on the A2 CPU Board Assembly. Use this information when the A2 Assembly is replaced. Jumper and Switch Settings Figure B-1 shows the default Jumper and Switch settings. When the A2 CPU Board Assembly is replaced, set the jumpers and switches to the default sides as shown in the gure.
  • Page 57 Index A1 Main Board Removal, 3-10 Keyboard Assembly Removal, 3-11 A2 CPU Board Assembly Removal, 3-10 A5 AC Inlet Board Assembly Removal, 3-10 Adjustable Components, 2-2 LCD Assembly Removal, 3-11 Adjustment, 2-1 Adjustment Procedure References, 2-5 Adjustment Program, 2-3 Manual Changes, A-1 Adjustment Tools, 2-2 After Service Product Safety Checks, 4-2 Analog Section, 4-5...

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