Agilent Technologies 6621A Service Manual Download Page 1

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MULTIPLE OUTPUT LINEAR SYSTEM

DC POWER SUPPLIES

Agilent MODELS 6621A, 6622A,

6623A, 6624A, and 6627A

* For instruments with higher Serial Numbers, a change page may be included.

SERVICE MANUAL

Agilent Part No 5957-6379

Microfiche Part No. 5957-6380

Agilent Model 6621A, Serial 3737A-03086 through 03145
US37370101 and up

Agilent Model 6622A, Serial 3736A-04021 through 04040
US37360101 and up

Agilent Model 6623A, Serial 3736A-05451 through 05530
US37360101 and up

Agilent Model 6624A, Serial 3735A-13801 through 14200
US37350101 and up

Agilent Model 6627A, Serial 3735A-02356 through 02510
US37350101 and up

Printed in Malaysia: September, 2001

Summary of Contents for 6621A

Page 1: ...rofiche Part No 5957 6380 Agilent Model 6621A Serial 3737A 03086 through 03145 US37370101 and up Agilent Model 6622A Serial 3736A 04021 through 04040 US37360101 and up Agilent Model 6623A Serial 3736A...

Page 2: ...or products returned to Customer from another country Agilent shall pay for return of products to Customer Warranty services outside the country of initial purchase are included in Agilent s product p...

Page 3: ...t and internal adjustments must be made by qualified service personnel Do not replace components with power cable connected Under certain conditions dangerous voltages may exist even with the power ca...

Page 4: ...tion of a bi stable push control Frame or chassis terminal On supply Terminal for Neutral conductor on permanently installed equipment Off supply Terminal is at earth potential Used for measurement an...

Page 5: ...4 1 4 3 REMOVAL AND REPLACEMENT 4 2 4 4 Top Cover Removal 4 2 4 5 Gaining Access to Assemblies in the Supply 4 2 4 6 4 2 4 7 40 Watt Output Board Removal 4 2 4 8 80 Watt Output Board Removal 4 4 4 9 R...

Page 6: ...CONTENTS Cont Section VI CIRCUIT DIAGRAMS 6 1 INTRODUCTION 6 1 6 2 FUNCTIONAL SCHEMATIC DIAGRAMS 6 1 6 3 COMPONENT LOCATION 6 1 Appendix A LOGIC SYMBOLOGY ii...

Page 7: ...oting and Board Isolation 4 15 4 7 4 8 Signature Analysis Test Setup 4 19 4 9 Output Board Troubleshooting 4 31 4 10 Low Voltage Output Board Waveforms During Self Exercise Routine 4 37 4 11 High Volt...

Page 8: ...hs 4 29 4 15 Microcomputer U312 Signal Measurements During the Self Exercise Routine 4 49 4 16 Signal Processor U327 Signal Levels 4 51 4 17 Typical Power Module Voltage Levels 4 54 4 18 Miscellaneous...

Page 9: ...provides a listing of replaceable parts for all electronic components and mechanical assemblies Circuit Diagrams Section VI contains functional schematics and component location diagrams The names th...

Page 10: ...ge of this manual a yellow Manual Change sheet supplied with the manual defines the differences between your supply and the supply described in this manual The yellow change sheet may also contain inf...

Page 11: ...can be individually calibrated over Operating Manual Correction factors are calculated during calibration and are stored in non volatile memory on the 2 5 Front Panel Most of the remote operations th...

Page 12: ...2 2...

Page 13: ...ajor circuits consist output boards interface and the front panel interface circuit transceivers U203 for the 8 data lines and 8 control lines handles data transfer between the microprocessor and the...

Page 14: ...s tests jumper W201 must be moved from the NORM RUN position to the SIG ANALYSIS position see paragraph 4 23 2 13 Address Bus and Address Decoder The microprocessor has 16 address lines A0 A15 allowin...

Page 15: ...ng programmed a programmed message or an error message The annunciators provide operating and status information The microprocessor uses the real time clock to determine when to update refresh the dis...

Page 16: ...2 6...

Page 17: ...U313 and amplifier U315A convert the digital input into an analog signal CV REF in the range of 0 to 10 V This signal is used as a reference voltage and is sent to the voltage control circuits see par...

Page 18: ...US RESET input line from the microcomputer resets the flip flops The status monitor circuit also receives OV SENSE and THERM inputs The THERM signal is received from the power module s in the power me...

Page 19: ...2 9...

Page 20: ...above V to the power module REF input The REF input is used by an internal control circuit that allows switching between the low medium and high rails The reference circuit includes a transistor P O U...

Page 21: ...ough the series pass elements in the power module so that they are never completely turned off The bleed circuit is activated via the power on circuit when the ON OFF signal is high The bleed circuit...

Page 22: ...2 12...

Page 23: ...which produces a 0 to 10 V signal that represents the output voltage magnitude which is also fed into S1 The 0 to 10 V signal is also sent back V READBACK to the secondary interface to indicate the ma...

Page 24: ...of U351 and CL error amplifier U350 The voltage drop I MON across the current monitoring resistor R408 is applied to summing junction S3 along with a reference voltage Based on this summing action er...

Page 25: ...Figure 2 7 Typical Output Range Characteristics 2 15...

Page 26: ...eight by paralleling the external OV lines The OV TRIP regardless of the state of the POV DISABLE signal As shown in Figure 2 9 OV TRIP is the output of a wired OR signal can gate and can be activate...

Page 27: ...ondition to the OV terminals via diode CR356 and transformer T301 as previously described Remote Overvoltage Trip Any output s OV can be triggered from its OV terminals by connection to a remote devic...

Page 28: ...2 18...

Page 29: ...paragraph 3 23 CC Load Effect paragraph 3 25 3 4 PERFORMANCE TESTS 3 5 Introduction The following paragraphs provide test procedures for verifying the supply s compliance with the specifications liste...

Page 30: ...3 2...

Page 31: ...3 3...

Page 32: ...ter between the S and S terminals of the output to be tested b Turn on the supply and select the desired output OUTPUT SELECT key on the front panel c Program the selected output channel to zero volts...

Page 33: ...steps a through f for each output in your supply 4 CV Source Effect This test measures the change in output voltage that results from a change in ac line voltage from the minimum to maximum value with...

Page 34: ...the output voltage to fall to 37 of the High Range Full Scale Voltage time constant Also measured is the time an output takes to change from full scale to zero volts and settle within the specified vo...

Page 35: ...tput to be tested as shown in Figure 3 6 b Turn on the supply and select the output to be tested OUTPUT SELECT key on the front panel c First program the selected output s voltage to its High Range Fu...

Page 36: ...a through j for each output in your supply 3 18 Transient Recovery Time This test measures the time for the output voltage to recover to within the specified value following a change from a low curren...

Page 37: ...test verifies that the fixed OV circuit will be activated when the output is about 20 above the High Range Full Scale Voltage value a Turn off the supply and connect an external power supply to the ou...

Page 38: ...output in your supply External OV Test This test checks the operation of the external OV circuit a Turn off the supply and connect the OV terminals of all outputs in parallel noting proper polarity F...

Page 39: ...operation It also checks that the negative current limit has two different values depending upon the output voltage a Turn off the supply and connect the output to be tested as shown in Figure 3 12 b...

Page 40: ...connect the ac power line through a variable voltage transformer b Connect the output to be tested as shown in Figure 3 3 with the DVM connected across the current monitoring resistor the load switch...

Page 41: ...for the output to stabilize under these initial conditions and then record the output voltage value g Adjust the transformer to 6 above the nominal line voltage h Wait 30 minutes and record the output...

Page 42: ...ers the CC mode with the displayed output voltage slightly less than the Low Range Full Scale Voltage value as read on the front panel display Check that the CC annunciator is on e Wait 30 minutes and...

Page 43: ...0 mA 12 5 mA 40WHV 4 2 mA 2 4 mA 80WHV 8 4 mA 4 9 mA g Repeat steps a through f for each output in your supply 3 38 Negative Current Limit CC Readback TC a Repeat steps a through d of paragraph 3 24 b...

Page 44: ...3 16...

Page 45: ...3 17...

Page 46: ...d be observed when handling static sensitive devices a Always turn power off before removing or installing printed circuit boards or components b Always store or transport static sensitive devices all...

Page 47: ...f the cover slightly and pull back to disengage it from the front panel c Remove the top cover Note that you can use the top cover assembly as a support when you open the top chassis in the next proce...

Page 48: ...4 3...

Page 49: ...and U339 on 80 W boards is defective and must be replaced 40 Watt Output Boards a Remove the output board as described in paragraph 4 7 b Carefully unsolder all 14 power module pins c Remove the power...

Page 50: ...of the wires from it including the RFI capacitor Then use a screwdriver inside the unit to press the mounting clip on one side of the line module and push from inside the unit that side of the module...

Page 51: ...4 6...

Page 52: ...oubleshooting procedures in this section apply only to earlier through hole board assemblies Surface mount GPIB assemblies are not repairable to the component level If defective the entire GPIB assemb...

Page 53: ...d as well as on each output board in the supply Table 4 3 lists the tests the boards tested and the error message that appears on the display if a particular test fails Note that two of the output boa...

Page 54: ...supply With W201 in this position error number 18 CAL LOCKED is generated if an attempt is made to turn on the calibration mode see Appendix A in the Operating Manual SIG ANALYSIS This position is use...

Page 55: ...4 10...

Page 56: ...4 11...

Page 57: ...4 12...

Page 58: ...tting may be lost and you must set the model number using the MODEL command short program can be used with BASIC installed in an GPIB assumed that the GPIB Interface address is 7 and the supply s GPIB...

Page 59: ...4 8 shows the general test setup for the signature analysis tests given in Tables 4 6 through 4 13 Note that jumper pack W202 can be installed in either of two positions as shown in Figure 4 8 The fol...

Page 60: ...4 15...

Page 61: ...4 16...

Page 62: ...4 17...

Page 63: ...4 18...

Page 64: ...4 19...

Page 65: ...4 20...

Page 66: ...ta probe to take signatures for each circuit at the output pins listed below These signatures apply to the firmware revsions listed Refer to Appendix A for previous versions Date code 2629 2839 Revisi...

Page 67: ...4 22...

Page 68: ...4 23...

Page 69: ...and set up the signature analyzer as shown below Signature Analyzer Input Edge Setting P201 PIN Connection START STOP CLOCK GND 11 12 15 4 Measurements Use the data probe to take signatures for each...

Page 70: ...4 25...

Page 71: ...4 26...

Page 72: ...4 27...

Page 73: ...4 28...

Page 74: ...4 29...

Page 75: ...nal from the signal processor U327 goes High Then the self exercise routine begins This routine runs independently of operating in this mode During the routine the display indicates HDW ERR CH ch as i...

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Page 78: ...4 33...

Page 79: ...4 34...

Page 80: ...4 35...

Page 81: ...4 36...

Page 82: ...4 37...

Page 83: ...4 38...

Page 84: ...4 39...

Page 85: ...4 40...

Page 86: ...4 41...

Page 87: ...4 42...

Page 88: ...4 43...

Page 89: ...4 44...

Page 90: ...4 45...

Page 91: ...4 46...

Page 92: ...4 47...

Page 93: ...4 48...

Page 94: ...ltage that appears on the selected input Its readback range is limited to approximately 0 1 to 10 corresponding to 0 1 V to 10 V on the input pins However any positive voltage from approximately 0 1 V...

Page 95: ...age comparator input signal when High causes OV DRIVE pin 6 to be High 8 V if POV DISABLE pin 3 is Low POV DISABLE pin 3 The POV DISABLE programmed overvoltage disable input signal when High prevents...

Page 96: ...cription in paragraph 4 30 4 Minus one diode drop 5 Indicates that hysteresis is involved in the trip voltage level and a transition from a lower voltage up to the indicated level must have occurred e...

Page 97: ...delay capacitor toward the DELAY CAP High level which when reached causes PCLR pin 26 to go High When BIAS TRIP is Low this signal causes a quick discharge of the external delay capacitor see Figure...

Page 98: ...4 53...

Page 99: ...dicated in the table the voltage levels were measured with the output voltage set to the maximum programmable value with no load connected to the output and at nominal line voltage 4 34 Miscellaneous...

Page 100: ...4 55...

Page 101: ...4 56...

Page 102: ...4 57...

Page 103: ...4 58...

Page 104: ...cal and mechanical parts on the 40 Watt Low Voltage 40WLV 40 Watt High Voltage 40WHV 80 Watt Low Voltage 80WLV and 80 Watt High Voltage 80WHV output board types The abbreviations 40WLV 40WHV etc are u...

Page 105: ...Digital to Analog Converter Double Chamber Diode Electrically Erasable Programmable Read Only Memory Electrolytic Erasable Programmable Read Only Memory Field Effect Transistor Flip Flop Full Wave Fix...

Page 106: ...701 04713 27014 17896 56289 01281 01295 Allen Bradley Company Corning Glass Works Fairchild Semiconductor Corp Hewlett Packard Company ITT International Rectifier Mepco Electro Corp Motorola Semicondu...

Page 107: ...tage 40WHV Bd 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 6621 6622 6623 6624 6627 06621 00004 06622 00004 06623 00004 06624 00007 06627 00002 5063 2304 Front Panel FRONT PANEL LTR FRO...

Page 108: ...NE CORD ASSY XFMR TO AC SWITCH FAN WIRE ASSY XFMR ASSY PRIMARY XFMR GPIB BIAS GPIB OUTPUT BD GPIB OUTPUT BD GPIB OUTPUT BD GPIB OUTPUT BD GPIB OUTPUT BD GPIB OUTPUT BD XFMR POWER 7V 5A XFMR POWER 20V...

Page 109: ...ACH M4X0 7 REF U335 SCR MACH M5X0 8 REF HANDLE MTG NUT HEX W LKWR REF FAN TO CHASS GNDSTD NUT HEX REF FTPNL GNDSTD THREADED INSERT REF CHAS TOP THREADED INSERT REF CHAS TOP LABEL REAR PANEL LABEL REAR...

Page 110: ...P 8 CONT CONN POST TYPE HDR 20 CONT CONK POST TYPE HDR 16 CONT CONN POST TYPE HDR 2 CONT CONN POST TYPE HDR 4 CONT CONN TRANSISTOR PNP SI FXD FILM 5 11K 1 1 8W FXD FILM 1 96K 1 1 8W FXD FILM 1 5K 1 1...

Page 111: ...EF U218 2 WASHER LK HLCL REF J201 2 STDF HEX HEAD REF U218 STUD STD PRS IN REF GPIB BD 1205 0366 5080 2101 0515 0886 0535 0004 2190 0584 2190 0584 0380 1679 0570 0639 IC LINE DRIVER TTL LS OCTAL IC FF...

Page 112: ...0 TAN 35V FXD CER 0 1uF 10 50V FXD ELECT 1uF 10 35VDC TAN FXD ELECT 4 7uF 10 TAN 35V FXD ELECT 1uF 10 35VDC TAN FXD ELECT 1uF 10 35VDC TAN FXD METPA 2200pF 20 250VDC FXD CER 120PF 5 100VDC FXD CER 0 1...

Page 113: ...80 4037 NOT USED 0180 0374 0160 4832 0180 0393 0180 1838 0160 4833 0180 0393 0160 4835 0160 4830 NOT USED 0160 4814 NOT USED 0180 3804 NOT USED NOT USED 0180 3804 NOT USED 0180 3804 NOT USED 0180 3804...

Page 114: ...4832 FXD ELECT 1uF 50V 10 TAN FXD CER 4700uF 10 100VDC FXD CER 10pF 5 100V FXD CER 220pF 5 100VDC FXD CER 1800pF 5 100VDC FXD CER 0 01uF 10 100VDC FXD CER 180pF 5 100VDC FXD CER 100pF 5 100VDC FXD CE...

Page 115: ...T USED 1901 0033 1901 0731 1901 0033 NOT USED FXD ELECT 1uF 10 35VDC TAN FXD METPA 0 022uF 20 250VDC FXD CER 0 01uF 10 100VDC FXD METPA 0 015uF 20 250VDC FXD ELECT 1uF 10 35VDC TAN FXD CER 0 022uF 10...

Page 116: ...NOT USED 2110 0716 2110 0763 2110 0685 2110 0767 2110 0383 2110 0916 2110 0916 2110 0383 2110 0713 2110 0916 2110 0767 2110 0383 NOT USED NOT USED 2110 0303 9140 0129 NOT USED 9140 0238 9100 1640 NOT...

Page 117: ...0665 1855 0549 1854 0477 0686 4725 0811 0610 0698 8911 0757 0403 0698 8672 0698 3700 8159 0005 0698 8672 0698 0085 0698 4123 0757 0402 8159 0005 NOT USED 0699 0208 0757 0284 NOT USED FERRITE BEAD CON...

Page 118: ...57 0458 0699 1722 FXD FILM 27 4K 1 1 8W FXD FILM 1 1K 1 1 8W FXD FILM ZERO OHMS F XD FILM 301 1 1 8W FXD FILM 499K 1 1 8W FXD FILM 4 99K 1 1 8W FXD FILM 5 11K 1 1 8W FXD FILM 4 99K 1 1 8W FXD FILM 20K...

Page 119: ...HMS FXD FILM ZERO OHMS FXD FILM 68 5 1 4W FXD FILM ZERO OHMS FXD FILM 68 5 1 4w FXD FILM ZERO OHMS FXD FILM 3 3 5 1 4w FXD FILM 6 98K 1 1 8W FXD FILM 12 7K 1 1 8W FXD FILM 14 7K 1 1 8W FXD FILM 27 4K...

Page 120: ...M 3 9K FXD FILM 499 1 1 8W FXD FILM 470 5 1 4W FXD FILM 12K 1 1 8W FXD FILM 12 1K 1 1 8W FXD FILM 130 1 1 8W FXD FILM 10K 1 1 8W FXD FILM 221 1 1 8W FXD FILM 2 49K 1 1 8W FXD FILM 221K 1 1 8W FXD FILM...

Page 121: ...250 5 5W FXD FILM 1 5K 5 3W FXD FILM 1 74M 1 1 8W FXD FILM 340K 1 1 8W FXD FILM 470 5 1 4W FXD FILM 2K 5 1 4W FXD FILM 07 5 2W FXD FILM 18 5 2W FXD FILM 150K 1 1 8W FXD FILM 2 49K 1 1 8W FXD FILM 33 5...

Page 122: ...ILM 2K 1 1 8W FXD FILM 15 8K 1 1 8W FXD FILM 15 4K 1 FXD FILM 1M 1 1 8W FXD FILM 316 1 1 4W FXD COMP 150 5 1 2W FXD FILM 7 5 5 2W FXD FILM 22 5 2W FXD FILM 10K 1 1 8W FXD FILM 15K 1 1 8W FXD FILM 1 5M...

Page 123: ...FILM 10K 1 FXD FILM 750 5 1 4W FXD FILM 2 2K 5 1 4W FXD FILM 28 7K 1 1 8W FXD FILM 61 9K 1 1 8W FXD FILM 10M 5 1 2W FXD FILM 4 7 5 1 4W FXD FILM 2 2K 5 1 4W FXD FILM 2 21K 1 1 8W FXD FILM 21 5 1 1 8W...

Page 124: ...1488 1826 1231 FXD FILM 15K 1 1 8W FXD FILM 34K 1 1 8W FXD FILM ZERO OHMS FXD FILM 470 5 1 4W FXD FILM 12 1K 1 1 8W FXD FILM ZERO OHMS FXD FILM 68 1 1 1 8W FXD FILM 139 1 1 8W FXD FILM 10K 5 1 4W FUS...

Page 125: ...D IC PWR HYBRID MATCHED W U338 IC OPAMP LO BIAS H IMP IC OP AMP IC OPAMP LO BIAS H IMP IC COMPARATOR PRCN DUAL IC OPAMP LO BIAS H IMP IC V RGLTR OV V SEN 8 DIP DIO ZNR 6 19V 2 PD 4mW DIO ZNR 20 5V 5 P...

Page 126: ...EF U339 MOD TO HS SCR MACH M4X0 7 REF U338 HS TO PCB REF U339 HS TO PCB SCR MACH M4X0 7 REF MOD HS M4X8L NUT HEX DBL CHAM REF U388 TO PCB INSUL XSTR REF Q321 325 HEAT SINK REF LM317 REF U302 HEAT SINK...

Page 127: ...n for each model is as follows This section contains functional schematic diagrams and component location diagrams for the power supply The power supply circuits are shown on Figure 6 1 through that i...

Page 128: ...6 2...

Page 129: ...6 3...

Page 130: ...nual Agilent Part No 5957 6377 for details 3 4 The line module connections are shown below The reference designators W1 W2 etc for the cable assemblies are for schematic reference only Use the Agilent...

Page 131: ...Figure 6 1 Power Distribution Schematic sheet 1 of 2 6 5...

Page 132: ...Figure 6 1 Power Distribution Schematic sheet 2 of 2 6 6...

Page 133: ...able for the surface mount GPIB assembly This board has a 4 position switch on it located next to U206 that replaces the function of connector P201 described on page 4 8 of this manual The switch sele...

Page 134: ...5385 1821 1256 XTAL EXTAL A8 A9 A10 A11 A12 A13 A14 A15 MODB MODA EVSS D0 D1 D2 D3 D4 D5 D6 D7 XIRQ R W AS RESET IRQ RXD TXD PD2 PD3 PD4 PD5 VDD PA7 PA6 PA4 PA3 PA2 PA1 PA0 PA5 E 31 NC1 VSS 1818 5681...

Page 135: ...Figure 6 3 Output 1 2 Board Component Location 6 9...

Page 136: ...Figure 6 3 Output 1 2 Board Schematic Diagram sheet 1 of 4 6 10...

Page 137: ...Figure 6 3 Output 1 2 Board Schematic Diagram sheet 2 of 4 6 11...

Page 138: ...Figure 6 3 Output 1 2 Board Schematic Diagram sheet 3 of 4 6 12...

Page 139: ...Figure 6 3 Output 1 2 Board Schematic Diagram sheet 4 of 4 6 13...

Page 140: ...Figure 6 4 Output 3 4 Board Component Location 6 15...

Page 141: ...Figure 6 4 Output 3 4 Board Schematic Diagram sheet 1 of 4 6 16...

Page 142: ...Figure 6 4 Output 3 4 Board Schematic Diagram sheet 2 of 4 6 17...

Page 143: ...Figure 6 4 Output 3 4 Board Schematic Diagram sheet 3 of 4 6 3 6 18...

Page 144: ...Figure 6 4 Output 3 4 Board Schematic Diagram sheet 4 of 4 6 3 6 19...

Page 145: ...Figure 6 5 Output 1 2 80W Board Component Location 6 21...

Page 146: ...Figure 6 5 Output 1 2 80W Board Schematic Diagram sheet 1 of 4 6 22...

Page 147: ...Figure 6 5 Output 1 2 80W Board Schematic Diagram sheet 2 of 4 6 23...

Page 148: ...Figure 6 5 Output 1 2 80W Board Schematic Diagram sheet 3 of 4 6 24...

Page 149: ...Figure 6 5 Output 1 2 80W Board Schematic Diagram sheet 4 of 4 6 25...

Page 150: ...f the symbol but are included to help the user interpret the symbol 3 Unless arrows indicate otherwise inputs are on left outputs are on right and signal flow is from left to right 4 In an array of tw...

Page 151: ...A 2...

Page 152: ...A 3...

Page 153: ...mon logic lines Figure A 5 shows how the Control block is usually represented Figure A 6 shows a quad D type flip flop with reset This can be redrawn as shown in Figure A 7 Note that the more complex...

Page 154: ...numbers is the same as the sequence of the affecting relationships Two affecting inputs labelled with different letters shall not have the same identifying number unless one of the letters is A If two...

Page 155: ...inputs and outputs are affected R Reset When active causes a flip flop to reset S Set When active causes a flip flop to reset V OR Identifies an input having an OR relationship with other inputs or ou...

Page 156: ...4245 fax 305 267 4286 Canada Agilent Technologies Canada Inc 5150 Spectrum Way Mississauga Ontario L4W 5G1 tel 1 877 894 4414 Australia New Zealand Agilent Technologies Australia Pty Ltd 347 Burwood...

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