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SERVICE MANUAL
GPIB DC Power Supplies
Agilent Series 668xA
For instruments with Serial Numbers:
Agilent Model 6680A: US36480101 and Above *
Agilent Model 6681A: US36400101 and Above *
Agilent Model 6682A: US36440101 and Above *
Agilent Model 6683A: US36420101 and Above *
Agilent Model 6684A: US36410101 and Above *
* This manual also applies to instruments with the older serial number format described on page 7.
For instruments with higher serial numbers, a change page may be included.
For instru
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CERTIFICATION Agilent Technologies certifies that this product met its published specifications at time of shipment from the factory. Agilent Technologies further certifies that its calibration measurements are traceable to the United States National Bureau of Standards, to the extent allowed by the Bureau's calibration facility, and to the calibration facilities of other International Standards Organization members. WARRANTY This Agilent Technologies hardware product is warranted against defec
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SAFETY CONSIDERATIONS GENERAL. This is a Safety Class 1 instrument (provided with terminal for connection to protective earth ground). OPERATION. BEFORE APPLYING POWER verify that the product is set to match the available line voltage, the correct line fuse is installed, and all safety precautions (see following warnings) are taken. In addition, note the instrument's external markings described under "Safety Symbols". WARNING. • Servicing instructions are for use by service-trained personnel.
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Safety Symbol Definitions Symbol Description Symbol Description Direct current Terminal for Line conductor on permanently installed equipment Alternating current Caution, risk of electric shock Both direct and alternating current Caution, hot surface Three-phase alternating current Caution (refer to accompanying documents) Earth (ground) terminal In position of a bi-stable push control Protective earth (ground) terminal Out position of a bi-stable push control (Intended for connection to exter
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Table of Contents Introduction ............................................................................................................................................................................ 7 Scope................................................................................................................................................................................... 7 Organization..............................................................................................
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Post-Repair Calibration..................................................................................................................................................... 62 When Required .............................................................................................................................................................. 62 Inhibit Calibration Jumper .........................................................................................................................
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1 Introduc tion Scope Organization This manual contains information for troubleshooting and repairing to the component level Agilent Series 668xA, 5-kilowatt power supplies. The remaining chapters of this manual are organized as follows: Chapter Des cription Cha pter 2 Verif ication procedures to determine the performance level of the supply either before or after repair. Cha pter 3 Troubleshooting procedures for isolating a problem, procedures for replacing the defective component an
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Re lated Documents Change Sheet There may or may not be a Manual Change sheet included with this manual (see Manual Revisions). If one is included, be sure to examine it for changes to this manual. Operating Manual Each power supply is shipped with an operating manual (see Replaceable Parts, Chapter 5 for part numbers) that covers the following topics: • Options, accessories, specifications, supplementary characteristics, output characteristic curve, typical output impedance curves. • Co
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Safety Considerations This power supply is a Safety Class I instrument, which means it has a protective earth terminal. This terminal must be connected to earth ground through a power source equipped with a 4-wire, ground receptacle. Refer to the "Safety Summary" page at the beginning of this manual for general safety information. Before operation or repair, check the power supply and review this manual for safety warnings and instructions. Safety warnings for specific procedures are located at
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2 V erification Introduction T his chapter provides test procedures for checking the operation of Agilent Series 668xA power supplies. The required test equipment is specified and sample performance test record sheets are included. Instructions are given for performing the tests either from the front panel or from a controller over the GPIB. Tests Two types of procedures are provided: Operation Verification tests and Performance tests. Ty pe of Test Pu rpose Operation Verification
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Table 2-1. Test Equipment Required Ty pe Req uired Characteristics Recommended Model 1 Dig ital Voltmeter R esolution: 10 nV @ 1V Agilent 3458A R eadout: 8 1/2 digits Accuracy: 20 ppm 1 A gilent 6682A, 6683A, Agilent 6684A: G uildline 9230/300 Current Monitor Resistor 0.00 1Ω ± 0.04%, 300A, 100W A gilent 6680A, 6681A Burster Type 1280 100 ± 0.05%, 1000A DC Power Supply DC P ower Source with current capability A gilent 6680A equal to UUT Electronic Load Range: Volta
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Programming The Tests Genera l Considerations Procedures are given for programming these tests either from the front panel keypad or from a GPIB controller. The procedures assume you know how to use the front panel keypad or how to program over the GPIB (see the Power Supply Operating Manual for more information). When using computer-controlled tests, you may have to consider the relatively slow (compared to computer and system voltmeters) settling times and slew rates of the power supply. Sui
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Operation Verification Tests Table 2-3 lists the requirements for operation verification, which is a subset of the performance tests. T able 2-3. Operation Verification Tests Test Refer To 1 Turn-On Checkout P ower Supply Operating Manual 2 Voltage Programming and Readback Accuracy Table 2-4 3 C urrent Programming and Readback Accuracy Table 2-5 Note: Record the results of Tests 2 and 3 in the appropriate Performance Test Record sheets Performance Tests Perf ormanc
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F igure 2-1. Constant Voltage (CV) Test Setup Ver ification 15
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Table 2-4. Constant Voltage (CV) Tests Action No rmal Result V oltage Programming and Readback Accuracy T his test verifies that the voltage programming, GPIB readback (GPIB system power supplies only), and front panel display functions are within specifications. With system power supplies, values read back over the GPIB should be the same as those displayed on the front panel. 1 Turn off the power supply and connect a DVM across +S and -S (see Fig. 2-1). 2 Turn on the power sup
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Table 2-4. Constant Voltage (CV) Tests (continued) Action No rmal Result CV Source Effect (cont) 2 Set the transformer to the nominal ac line voltage. Connect the DVM across +S and -S (see Fig. 2-1). 3 T urn on the power supply and program the current to its maximum programmable value and the voltage to its full-scale value (see Table 2-2). 4 A djust the load to produce full-scale current (see Table 2-2) as shown on CV annunciator is on. If it is not, adjust the front panel dis
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Table 2-4. Constant Voltage (CV) Tests (continued) Action Normal Result T ransient Recovery Time T his test measures the time required for the output voltage to return to within 100mV of its final value following a 50% change in output load current. Measurements are made on both the unloading transient (from full load to 1/2 load) and the loading transient (from 1/2 load to full load). 1 T urn off the power supply and connect an oscilloscope across +S and -S (see Fig. 2-1). 2 Turn
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Constant Current (CC) Tests Test Setup C onnect the appropriate current monitoring resistor (see Table 2-l) as shown in Fig. 2-3. The accuracy of the resistor must be as specified in the table. Test Procedures T he test procedures are given in Table 2-5. The tests are independent and may be performed in any order. The CC tests are: • Current Programming and Readback Accuracy. • CC Load Effect. • CC Source Effect. • CC Noise (PARD). Table 2-5. Constant Current (CC) Tests Action Normal Result
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Table 2-5. Constant Current (CC) Tests (continued) Action Normal Result CC Noise (PARD) (cont) 2 Measure the residual noise on the DVM with the power supply turned off. Noise generated by other equipment may affect this measurement and should be removed or factored out. 3 Turn on the power supply and program the current to its full scale value and the voltage to its maximum programmable value (see Table 2-2). 4 Adjust the load in the CV mode for full-scale voltage (see Table 2-2) as The power su
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Table 2-5. Constant Current (CC) Tests (continued) Action Normal Result CC Source Effect This test measures the change in output current resulting from a change in ac line voltage from its minimum to its maximum value within the line voltage specifications. It is recommended that you use averaged readings for Steps 6 and 8 of this test (see "Averaging AC Measurements" at the end of this chapter) . 1 Turn off the power supply and connect the ac power input through a variable-voltage transformer.
