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Agilent Technologies 4338B, Service Manual

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Agilent Technologies 4338B Service Manual Download Page 39

Range

Resistor

and

Current

Sense

Amplier

Sections

These

sections

measure

current

owing

through

the

DUT

.

Figure

4-5

shows

this

section's

block

diagram.

Figure

4-5.

Range

Resistor

and

Current

Sense

Amp

.

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.

The

current

sense

amplier

,

which

is

a

dierential

amplier

,

amplies

the

voltage

across

the

range

resistor

.

T

roubleshooting

4-7

Summary of Contents for 4338B

Page 1: ...S 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 Agilent Part No 04338 90033 Printed in JAPAN March 2001 ...

Page 2: ...y 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 Component Test PGU Kobe 1 3 2 Murotani Nishi ku Kobe shi Hyogo 651 2241 Japan c Copyright Agilent Technologies Japan Ltd 1996 2000 2001 ...

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 iii ...

Page 4: ...Circuits Operating personnel must not remove instrument covers Component replacement and internal adjustments must be made by quali ed maintenance personnel Do not replace components with the power cable connected Under certain conditions dangerous voltages may exist even with the power cable removed To avoid injuries always disconnect power and discharge circuits before touching them DO NOT Servi...

Page 5: ...service facility designated by 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 Agilent Technologies warrants that its software and rmware designated by Agi...

Page 6: ... 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 For any assistance contact your nearest Agilent Technologies Sales and Service O ce Addresses are provided at the back of this manual vi ...

Page 7: ...ign denotes a hazard It calls attention to a procedure practice condition or the like which if not correctly performed or adhered to could result in injury or death to personnel This Caution sign denotes a hazard It calls attention to a procedure practice condition or the like which if not correctly performed or adhered to could result in damage to or destruction of part or all of the product Note...

Page 8: ...ustments Chapter 2 describes the adjustments required to ensure that the 4338B is within its published speci cations after it has been repaired or it fails the performance tests Chapter 3 Assembly Replacement Chapter 3 provides the information on replacing the 4338B assemblies The information includes replaceable assembly lists and removal and installation procedures Chapter 4 Troubleshooting Chap...

Page 9: ...ce Measurement Adjustment 2 5 Equipment 2 5 Setup 2 5 3 Assembly Replacement Introduction 3 1 Ordering Information 3 1 Restored Exchange Assemblies 3 1 Replacing the A2 CPU Board Assembly 3 2 Replaceable Assembly List 3 2 Replaceable Mechanical Parts List 3 5 Disassembly Procedures 3 9 Tools and Fasteners 3 9 Cover Removal 3 9 A1 Main Board Removal 3 10 Removal Procedure 3 10 A2 CPU Board Assembly...

Page 10: ... References 4 13 Check 1 DC DC Converter Output Voltage 4 13 Check 2 LCD Displays Anything 4 14 Check 3 LCD Operates Correctly 4 14 Check 4 Any Error Message on LCD 4 14 Check 5 CPU Related Error Message 4 14 Check 6 CPU Power LED Lights 4 14 Check 7 Any Error Code on LED 4 15 Check 8 CPU Fuse High Lead Voltage 4 16 Check 9 Fuse and Line Switch 4 16 Check 10 DC DC Converter Input Voltage 4 17 Chec...

Page 11: ...ard Assembly LED Light Sequence 4 15 4 12 Location of High Lead of A2F1 Fuse 4 16 4 13 Test Pin Locations 4 17 4 14 DC DC Converter Output Connector 4 18 4 15 Transformer Secondary Voltage Check 4 19 B 1 Jumper and Switch Settings B 1 Tables 1 1 Required Equipment 1 2 1 2 Required Language Extensions 1 2 2 1 Related Adjustment 2 2 3 1 Replaceable Major Assembly List 3 3 3 2 A2 CPU Board Assembly R...

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Page 13: ...llow Manual Changes supplement or have a di erent manual part number This sheet contains change information that explains how to adapt the manual to the newer instrument In addition to change information the supplement may contain information for correcting errors Errata in the manual To keep this manual as current and accurate as possible Agilent Technologies recommends that you periodically requ...

Page 14: ...e 42091A3 1 A Computer No Substitute HP 9000 series 200 or 3004 RAM 4M bytes 1 A Operating System BASIC 5 1 or higher 98616A 1 A Adjustment Program No substitute Agilent PN 04338 65005 1 A 1 Troubleshooting 2 Adjustment 3 This model is also included in the 42100A Four Terminal Pair Resistor Set 4 Excluding the 9826A Table 1 2 Required Language Extensions Name Ver CLOCK 5 0 COMPLEX 5 1 CRTA 5 1 CRT...

Page 15: ...onsideration This chapter contains NOTEs CAUTIONs and WARNINGs which must be followed to ensure operator safety and to maintain the instrument in a safe and serviceable condition The adjustment covered in this chapter should be performed only by a quali ed person who is aware of the hazards Warning Any interruption of the protective ground conductor inside or outside the instrument or disconnectio...

Page 16: ...t 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 Table 2 1 Related Adjustment Assembly Replaced Required Adjustment A1 Main Board Assy Resistance Measurement Adjustment A2 CPU Board Assy without ROM None1 A5 AC Inlet Board Assy None LC...

Page 17: ... item Figure 2 1 Adjustment Program Flow INITIAL SETUP de nes the standards calibration values Update the standard s calibration values if necessary Resistance Measurement Adjustment obtains the data to adjust the actual measurement resistance to the standards value and writes the data both to the 4338B internal EEPROM and to the unit serial number dependent le on the disk This adjustment should b...

Page 18: ...Installation 1 Turn on the computer and bring up the BASIC system Refer to the Table 1 2 for the required language extensions 2 Set the Mass Storage Unit Speci er to the drive directory where the adjustment program exists using the MSI command 3 Load the program ADJ4338B by pressing LOAD ADJ4338B 4Return5 or 4Enter5 4 Execute the program by pressing RUN Note In the program the 4338B is referred as...

Page 19: ...nt updates the data to adjust the measurement resistance to the standard values Equipment Standard Resistors 42030A Open Termination 42090A Short Termination 42091A Setup This setup obtains the range resistor adjustment data and the process ampli er attenuator adjustment data Figure 2 2 Range Resistor Adjustment Setup Perform the following steps as the program instructs 1 Connect the speci ed term...

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Page 21: ...l number complete instrument serial number the description and function of the part and the quantity of parts required Address the order to the nearest Agilent Technologies o ce Restored Exchange Assemblies Some replacement assemblies are available as either new or restored assemblies The restored assembly is more economical than a new assembly and as with new assemblies a 90 day warranty applies ...

Page 22: ...w assembly as long as the 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 When the A2 assembly is replaced make sure that the jumpers and switches on the A2 assembly are in the default position as shown in Appendix B Replaceable Asse...

Page 23: ...04263 80901 1 DC DC Converter Unit 4 04263 66532 1 A2 CPU Board Assembly w o ROM 04263 00604 1 Case Shield1 0515 1550 4 Screw M3 5 04338 66504 1 A4 Keyboard Assembly 04338 25151 1 Rubber Key 0515 1550 1 Screw M3 6 04263 61010 1 LCD Assembly 04263 25003 1 Filter Transparent 0515 1550 2 Screw M3 7 04338 66551 1 A1 Main Board Assembly 1 Included in 04263 66532 Assembly Replacement 3 3 ...

Page 24: ... 1 A2U1 EEPROM 3 04338 85031 1 A2U11 ROM Rev 1 00 Table 3 3 Replaceable Assembly List Reference Designation Agilent Part Number Qty Description A1C500 0180 4334 1 Capacitor 22000 F for power supply A1C501 0180 4334 1 Capacitor 22000 F for power supply A5SW1 3101 3171 1 Line Switch A5VR1 0837 0237 1 Varistor A5VR2 0837 0237 1 Varistor 3 4 Assembly Replacement ...

Page 25: ...0001 1 Front Bezel 2 6 04263 00605 1 Sub Panel Hidden 2 0515 0914 4 Screw M3 Hidden 2 0515 1550 2 Screw M3 Hidden 2 0160 4808 4 Capacitor 470 pF Hidden 2 1901 1250 8 Diode Hidden 2 7 1250 0252 4 BNC Connector 2 2950 0035 4 Nut 2 5040 3324 4 Insulator 2 5040 3325 4 Insulator Hidden 2 04263 01221 4 Lug Terminal Hidden 2 8 1510 0130 1 Binding Post 2 2190 0067 1 Washer Hidden 2 2950 0006 1 Nut Hidden ...

Page 26: ...ion 1 04263 61615 1 GPIB Connector with atcable1 2 2110 0565 1 Fuse Holder 2110 0202 1 Fuse 0 25 A Slow Blow 230V 2110 0201 Fuse 0 5 A Slow Blow 115V 3 0515 1551 2 Screw M3 4 04338 00102 1 Chassis 5 2190 0054 1 Washer 2950 0054 1 Nut 1 Includes two sets of screw washer and nut 3 6 Assembly Replacement ...

Page 27: ... Washer Spring M3 5 0515 1550 7 Screw M3 for A1 and A2 04339 24006 4 Stando Hidden for A1 6 5040 3347 2 Plate Hidden Chassis Reverse side 0460 0616 150 mm 2 2 Adhesive Tape for Plate 7 04263 07001 2 Gasket 0515 1550 4 Screw M3 8 0370 2862 1 Button Line Switch 04339 23001 1 Shaft Line Switch 0535 0031 1 Nut for Shaft 9 04339 25002 2 Support Line Switch Plate 0515 0914 2 Screw M3 Flat Head 10 04263 ...

Page 28: ... 2 04263 61602 1 Cable Assembly A A 04339 25004 1 Core Holder 0515 1550 1 Screw M3 3 04263 61604 1 Cable Assembly B B 04339 25004 1 Core Holder 0515 1550 1 Screw M3 4 04263 61605 1 Cable Assembly C C 04339 25004 1 Core Holder 0515 1550 1 Screw M3 5 04338 61603 1 Cable Assembly 6 04339 61614 1 Wire Assy Binding Post 3 8 Assembly Replacement ...

Page 29: ...ical 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 Cover Removal The following procedure is common for gaining access to any of the assemblies Figure 3 1 Cover Removal 1 Remove the two screws whi...

Page 30: ... side of the A2 assembly 3 Disconnect the atcable assembly which is connected to the GPIB connector on the rear panel from the rear right side of the A2 assembly 4 Remove the four screws that secure the A2 assembly to the stud 5 Remove the at cable assembly which is connected to the A1 main board assembly on the bottom while sliding the A2 assembly toward front 6 Remove the A2 assembly from the ch...

Page 31: ...y 3 Remove the two at head screws that secure the front panel from the bottom 4 Remove the side trim label from both sides of the front bezel 5 Remove the four screws that secure the front panel bezel to the chassis from both sides 6 Place the front panel assembly so that the front panel faces down 7 Remove the two screws that secure the LCD to the front panel bezel 8 Remove the LCD assembly from ...

Page 32: ...ecures 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 10 Unscrew the nut which connects the BNC connector housing to the sub panel 11 Remove the BNC connector 3 12 Assembly Replacement ...

Page 33: ...is supplied to the instrument and its protective covers are removed This type of servicing must be performed only by service trained personnel who are aware of the hazards involved for example re and electrical shock When serving can be performed without power applied to the instrument remove power from the instrument Before any repair is completed ensure that all safety features are intact and fu...

Page 34: ...t for any signs of abnormal internally generated heat such as discolored printed circuit boards and components damaged insulation or evidence of arcing Determine the cause and repair 2 Use an ohmmeter which can accurately measure 0 1 to check the resistance from the instrument enclosure to the power cord s ground pin The resistance must be less than 0 1 Flex the power cord while making this measur...

Page 35: ...ough the DUT Figure 4 1 Voltage Current Ratio Measurement Principle In Figure 4 1 a DUT is connected in series with a signal source voltmeter V and ammeter A If the ammeter measures i amperes when the source voltage is v volts the DUT s impedance Zx is expressed by Zx v i The DUT resistance R is the real part of Zx expressed in the complex real imaginary number format Zx R jX where j is the imagin...

Page 36: ...sense ampli er measures the voltage across the range resistor which is proportional to the current owing through the DUT The voltage sense ampli er measures the voltage across the DUT The process ampli er switches these two voltages to be converted into digital data The CPU calculates DUT resistance derived from impedance from the vector ratio of these two voltages and displays the result on the L...

Page 37: ...or and outer shield of the HCUR connector The vector current owing through the DUT is measured by the current sense ampli er in terms of the vector voltage across the range resistor The vector voltage across the DUT is measured by the voltage sense ampli er The process ampli er selects one of the above two vector voltages The selected voltage is processed according to measurement conditions such a...

Page 38: ...ed 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 Figure 4 4 Signal Source Section Block Diagram 4 6 T roubleshooting ...

Page 39: ...e Resistor and Current Sense Amp 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 The current sense ampli er which is a di erential ampli er ampli es the voltage across the range resistor T roubleshooting 4 7 ...

Page 40: ...he DUT via the High Potential HPOT and Low Potential LPOT connectors The output of the voltage sense ampli er is fed back to the signal source section for dry circuit measurement SW1 in the process ampli er selects the inputs from the voltage sense ampli er and current sense ampli er to be processed The selected signal is attenuated according to the range resistor setting The lter passes the funda...

Page 41: ...handler interface on the A1 Assembly allows the 4338B communicate with an external handler The A2 CPU Board Assembly includes a processor ROM EEPROM jumpers switches and LEDs ROM A2U11 stores the rmware which controls all the 4338B s operation and functions The ROM is mounted in a socket for easy replacement The EEPROM A2U1 stores the unit unique data such as the adjustment data and the operator u...

Page 42: ...mary tap of the transformer 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 The transformer secondary voltage is approximately 14 V The ac voltage is recti ed and ltered by circuitry on the A1 Main Board Assembly and produces approximate...

Page 43: ... 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 The troubleshooting procedure therefore only isolates the defective assembly T roubleshooting 4 11 ...

Page 44: ...Figure 4 9 Troubleshooting Flow 4 12 T roubleshooting ...

Page 45: ...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 4 If passed proceed to Check 2 LCD Displays Anything otherwise proceed to Check 9 Fuse and Line Switch Figure 4 10 DC DC Converter Output Voltage Check Table 4 1 DC DC Converter Output Voltage Connected Test Pad Test Pin 0 Range 5 V 500 5...

Page 46: ...LCD 1 Turn o the 4338B 2 Turn on the 4338B while watching the LCD 3 Check if the LCD displays any error message 4 If an error has NOT occurred replace the A1 Main Board Assembly otherwise proceed to Check 5 CPU Related Error Message Check 5 CPU Related Error Message 1 If the error message is one of the following replace the A2 CPU Board Assembly otherwise replace the A1 Main Board Assembly a ROM T...

Page 47: ... 4 11 4 If LEDs light as the sequence replace the LCD Assembly otherwise possibly HALT doesn t turn o or BERR lights replace the A2 CPU Board Assembly Note When replacing the A2 CPU Board Assembly refer to Replacing the A2 CPU Board Assembly in Chapter 3 for handling the ROM and EEPROM on the A2 Assembly Figure 4 11 CPU Board Assembly LED Light Sequence T roubleshooting 4 15 ...

Page 48: ... is most suspicious Replacing only the fuse may x the problem Note When replacing the A2 CPU Board Assembly refer to Replacing the A2 CPU Board Assembly in Chapter 3 for handling the ROM and EEPROM on the A2 Assembly Figure 4 12 Location of High Lead of A2F1 Fuse 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 ...

Page 49: ... 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 3 If the voltage is in range proceed to the Check 11 DC DC Converter Open Output Voltages otherwise proceed to the Check 12 Transformer Secondary Voltage Figure 4 13 Test Pin Locations T roubleshooting 4 17 ...

Page 50: ...ltimeter 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 5 If passed replace the A1 Main Board Assembly otherwise replace the DC DC Converter Assembly Figure 4 14 DC DC Converter Output Connector Table 4 2 DC DC Converter Open Output Voltages Pin Pin 0 Voltage Range 1 2 5 160 1 V 4 3 1260 6 V 5 3 01260 6 V 4 1...

Page 51: ...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 5 If passed replace the A1 Main Board otherwise replace the transformer Figure 4 15 Transformer Secondary Voltage Check T roubleshooting 4 19 ...

Page 52: ......

Page 53: ...rial number Instruments manufactured after the printing of this manual may be di erent from those documented in this manual Later instrument versions will be documented in a manual changes supplement that will accompany the manual shipped with that instrument If your instrument serial number is not listed on the title page of this manual or in Table A 1 it may be documented in a yellow MANUAL CHAN...

Page 54: ......

Page 55: ...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 Figure B 1 Jumper and Switch Settings Default Jumper and Switch Settings B 1 ...

Page 56: ......

Page 57: ...al Information 1 1 H How To Use This Manual viii I Instruments Covered by This Manual 1 1 K Keyboard Assembly Removal 3 11 L LCD Assembly Removal 3 11 M Manual Changes A 1 O Ordering Information 3 1 Overall Block Diagram 4 4 Overall Measurement Theory 4 3 P Power Supply Section 4 10 Program Installation 2 4 R Range Resistor Adjustment 2 5 Range Resistor and Current Sense Ampli er Sections 4 7 Rela...

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