HP-428B-Manual 电路图.pdf

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1、Errata Title it takes a lot of hours to scan and replicate a manual. I just want this used in the spirit in which is it given. Agilent if you have questions or wish to include this in your archive, please contact me. RadioFans.CN 收音机爱 好者资料库 Page intentionally left blank. RadioFans.CN 收音机爱 好者资料库 Radi

2、oFans.CN 收音机爱 好者资料库 OPERATING AND SERVICE MANUAL -hp- Part No. 00428-90003 MODEL 428B CLIP-ON DC MILLIAMMETER Serials Prefixed: 995- and above Appendix A, Manual Backdating Changes adapts this manual to instruments with earlier serial prefixes. Copyright Hewlett-Packard Company 1970 P.O. Box 301, Lo

3、veland, Colorado, 80537 U.S.A. Printed: NOV 1970 Model 428B TABLE OF CONTENTS MAINTENANCE 14 GENERAL INFORMATION 2 1-1. INTRODUCTION 2 1-7. INSTRUMENT AND MANUAL IDENTIFICATION. 2 INSTALLATION 3 2-1. UNPACKING AND MECHANICAL INSPECTION. 3 2-4. OPERATION CHECK. 3 2-6. INSTALLATION. 3 2-8. POWER REQUI

4、REMENTS. 3 2-10. OPERATION ON 115 OR 230 VOLTS. 3 2-13. THREE CONDUCTOR POWER CABLE. 3 2-15. RACK MOUNT MODEL. 3 2-17. PREPARATION FOR STORAGE AND SHIPMENT. 3 220. STORAGE. 3 OPERATING INSTRUCTIONS 5 3-1. INTRODUCTION. 5 7 7 7 7 7 3-3 OPERATING PRECAUTIONS. 5 3-4. OPERATING CONSIDERATIONS. 5 3-5. IN

5、TERCHANGING PROBE HEADS. 5 3-7. EFFECT OF MEASUREMENT ON CIRCUIT. 5 3-12. EFFECT OF CIRCUIT ON MEASUREMENT. 5 3-19. Magnetic Fields. 6 3-26. OPERATING PRACTICES. 6 3-27. MECHANICAL OPERATION OF PROBE. 6 3-29. DEGAUSSING OF PROBE HEAD. 6 3-33. ELECTRICAL ZERO SET. 6 3-37. POLARITY OF CURRENT. 6 3-39.

6、 INCREASING THE ABSOLUTE SENSITIVITY 7 9 9 5-1. INTRODUCTION. 14 5-3. TEST EQUIPMENT REQUIRED. 14 5-5. IN-CABINET PERFORMANCE CHECKS. 14 5-7. CLEANING OF PROBE JAWS. 14 5-10. ELECTRICAL ZERO SET. 14 5-13. RANGE CHECK. 15 5-15. METER TRACKING. 15 5-17. OUTPUT CALIBRATION. 15 5-19. FREQUENCY RESPONSE.

7、 15 5-21. AC OVERLOAD. 16 5-23. NOISE CHECK. 16 5-25. ADJUSTMENT PROCEDURE. 16 5-27. POWER SUPPLY. 16 5-29. MECHANICAL ZERO SET. 16 5-31. DC AMPLIFIER BALANCE. 16 5-34. ALIGNMENT. 17 5-35. OSCILLATOR BALANCE. 17 5-37. OSCILLATOR FREQUENCY. 17 5-39. OSCILLATOR LEVEL. 17 5-41. DETECTOR GATE. 17 5-43.

8、TUNED AMPLIFIER. 17 5-44. Equipment Setup. 17 5-46. Input Alignment. 17 5-48. Interstage Alignment. 17 5-50. DETECTOR PHASE ADJUSTMENT. 17 5-53. Preliminary Adjustment. 18 5-54. Preset the controls as follows: 18 5-55. Drive Balance Adjustment. 18 5-59. TROUBLESHOOTING. 19 5-60. FRONT PANEL TROUBLES

9、HOOTING. 19 5-63. DETAILED TROUBLESHOOTING. 19 5-64. Probe Check. 19 5-66. Power Supply Check. 19 5-71. Oscillator - Buffer Amp. Check. 21 5-80. Synchronous Detector. 21 REPLACEABLE PARTS 23 6-1. INTRODUCTION. 23 6-4. ORDERING INFORMATION. 23 6-6. NON-LISTED PARTS. 23 CIRCUIT DIAGRAMS 29 7-1. INTROD

10、UCTION. 29 7-3. BLOCK DIAGRAM. 29 7-5. SCHEMATIC DIAGRAMS. 29 7-7. COMPONENT LOCATION DIAGRAMS. 29 MANUAL BACKDATING CHANGES 36 3-41. CURRENT CHECK LOOPS. 3-44. NULLING CURRENTS. 3-46. USE OF OUTPUT JACK. 3-48. With Oscilloscope. 3-50. With Recorder. THEORY OF OPERATION 4-1. INTRODUCTION. 4-3. THEOR

11、Y OF OPERATION. 4-9. CURRENT PROBE. 4-19. 20 kHz OSCILLATOR. 4-23. HEAD-DRIVE AMPLIFIER. 4-25. DETECTOR GATE AMPLIFIER. 9 9 11 11 11 4-28. 40 kHz INPUT/AMPLIFIER CIRCUIT. 11 4-30. SYNCHRONOUS DETECTOR AND FILTER (C24). 11 4-36. DC AMPLIFIER. 12 4-43. NEGATIVE FEEDBACK CURRENT CIRCUIT. 12 4-45. 40 kH

12、z PHASE SHIFTER. 12 4-48. POWER SUPPLY. 12 Model 428B LIST OF TABLES Table 1-1 Specifications1 Table 5-1. Recommended Test Equipment.13 Table 6-1. Replaceable Parts24 LIST OF ILLUSTRATIONS Figure 1-1. Model 428B Clip-On Milliammeter2 Figure 3-1. Measurement Procedures4 Figure 3-2. Polarity of Curren

13、t.6 Figure 3-3. Increasing The Absolute Sensitivity. 7 Figure 4-1. Block Diagram8 Figure 4-2. Simplified Block.9 Figure 4-3. Magnetic Mechanical Analogy.10 Figure 4-5. 428B Flux Gate.10 Figure 4-4. Basic Flux Gate.10 Figure 4-6. Waveforms.10 Figure 4-7. Detector Bridge.11 Figure 4-8. Negative Feedba

14、ck12 Figure 4-9. 90 Phase Shift12 Figure 5-1. Cleaning Probe Jaws.14 Figure 5-2. Electrical Zero Set.14 Figure 5-3. Range Check.15 Figure 5-4. AC Overload.16 Figure 5-5. Oscillator Balance Probe.17 Figure 5-6. Detector Phase Adjustment.17 Figure 5-7. Detector Phase Display.18 Figure 5-9. Detailed Tr

15、oubleshooting Tree.20 Figure 6-1. Parts Breakdown, current probe.28 Figure 7-1. Block Diagram.30 Figure 7-2. Component Locator For Circuit Board Part No. 00428-6650131 Figure 7-3. Front Panel Component Locator.31 Figure 7-4 Rear Panel Component Locator.31 Figure 7-5. Power Supply.32 Figure 7-6. Bloc

16、k Diagram.33 Figure 7-7. Component Locator for Circuit Board Part No. 00428-6650134 Figure 7-8. Front Panel Component Locator.34 Figure 7-9 Rear Panel Component Locator.34 Figure 7-10. Metering Circuit35 Figure A-1. 428B Side Views.37 Figure A-2 Backdating Schematics for 428B38 Figure A-3 Backdating

17、 Schematics for 428B39 Model 428B 1 428B SPECIFICATIONS Table 1-1 Specifications Current Range: 1 mA to 10 A full-scale, nine ranges. Accuracy: 3% of full-scale 0.15 mA, from 0C to 55C. (When instrument is calibrated to probe). Probe Inductance: Less than 0.5 H. Probe Induced Voltage: Less than 15 m

18、V peak (worst case at 20 kHz and harmonics). Output: Variable linear output level with switch position for calibrated 1 V into open circuit (corresponds to full-scale deflection). 1.5 V Max. into open circuit in uncalibrated position. 0.73 .01 V into 1 kin calibrated position. Noise: 1 mA Range, 15

19、mV rms across 1 k. 3 mA Range, 5 mV rms across 1 k . 10 mA thru 10 A Ranges, 10 mA output Frequency Response AC Overload -hp- Model 3310A Function Generator OscilloscopeDC to 40 kHz 100 mV/cm 3% Frequency Response AC Overload Troubleshooting -hp- Model 130C 200V/cm Oscilloscope Resistor50 Ohms 1%Fre

20、quency Response AC Overload -hp- Part No. 0698-3128 0698-8155 DC Voltmeter .25% at 730 mVOutput Calibration-hp- Model 3430A 3469B DC Digital Voltmeter AC VoltmeterResolves 2 mV Battery operated Noise Check-hp- Model 4038 AC Portable Voltmeter Resistor1 kilohm 1%Output Calibration Noise Check -hp- Pa

21、rt No. 11034-82601 Volt-OhmmeterInput impedance: 1 megohmTroubleshooting-hp- Model 427 A Multi-Function Meter Oscilloscope ProbeInput Impedance: 10 megohmsAll Troubleshooting-hp- Model 10001A Resistive Divider Probes CounterReads 40 kHz 20 HzAlignment Troubleshooting -hp- Model 5321 B Capacitor.0082

22、 F 10% 300 VdcAlignment Resistor390 Ohms 5% 1/2 WAlignment Model 428B SECTION V MAINTENANCE 5-1. INTRODUCTION. 5- 2. This section contains the service information which is required to properly maintain the 428B Clip-On Milliammeter. Included are performance checks, adjustment and calibration procedu

23、res, and servicing and troubleshooting information. 5-3. TEST EQUIPMENT REQUIRED. 5-4. The test equipment required to perform the operations outlined in this section is listed in Table 5-1. This table includes the type of equipment, critical specifications, purpose, and recommended model. If the mod

24、el recommended is not available, equipment which meets or exceeds the critical specifications listed may be substituted. 5-5. IN-CABINET PERFORMANCE CHECKS. 5-6. The performance checks described in Paragraphs 5-7 through 5-24 are front panel procedures designed to compare the Model 428B with its pub

25、lished specifications. These tests may be incorporated into periodic maintenance, post repair, and incoming quality control checks. The performance checks should be conducted before any attempt is made to adjust or calibrate the instrument. During the in-cabinet performance checks, the Model 428B sh

26、ould be connected to the ac line through a variable voltage device so that line voltage may be varied 10% from 115 or 230 Vac to assure that the instrument operates correctly at various ac line voltages. 5-7. CLEANING OF PROBE JAWS. 5-8. When the probe shows excessive sensitivity to the magnetic fie

27、lds around it, the probe jaws should be cleaned (to determine excessive sensitivity, see Paragraph 5-24 Step a). Excessive sensitivity to external fields can be caused by foreign material between the probe jaws or by overheating (see Paragraph 3-3 Step d). The probe jaws should always be cleaned pri

28、or to calibration, adjustment or repair of the 428B. 5-9. To clean the probe jaws, open the probe and brush off the mating surfaces with the brush which is supplied with the instrument. If the brush will not remove the contaminant, disassemble the probe and clean it with a pencil eraser as illustrat

29、ed. When reassembling the probe, be sure that the arrow on the body of the probe points to the heavy red wire as shown in Figure 6 -1 . Figure 5-1. Cleaning Probe Jaws. 5-10. ELECTRICAL ZERO SET. 5-11. In the following procedure the numbers in parentheses refer to Figure 5-2. a. Connect the 428B to

30、the power line through a variable transformer . b. Turn on power (1) and allow about two minutes of warmup time. c. Place probe (2) away from any stray fields such as meter magnets, or open core transformers. d. Insure that the probe jaws (3) are completely closed (Paragraph 5-24 Step a, outlines a

31、way to do so). e. Set RANGE switch (4) to 1 mA. f.Zero-set the 428B with the ZERO (5) control. If the meter cannot be zeroed, degauss the probe (Paragraph 3-29) or clean the probe jaws (Paragraph 5-8). g. Change the line voltage from 103 to 127 volts ( 10%) and read zero drift on the 428B meter. Zer

32、o drift should not exceed .03 mA. Figure 5-2. Electrical Zero Set. 14 Model 428B 5-12. Allow a 30 minute warmup and stabilization period before conducting the following performance checks. 5-13. RANGE CHECK. 5-14. Figure 5-3 illustrates the test arrangement recommended. A de meter calibrator is requ

33、ired for this test. a. Zero the 428B on the 1 mA range. b. Switch the 428B and the meter calibrator to the 10 amp range. Set the meter calibrator for 5 amps of output (maximum output for the recommended 6920B). Connect a test lead between the output terminals of the meter calibrator and loop the tes

34、t lead through the jaws of the 428B twice (see Figure 3-3). The 428B should read 10 amps 0.3 amp. c. Switch the meter calibrator to the 1 amp range and adjust it for 1 amp of output. Remove the test lead from the 428B Probe jaws. Zero the 428B, then loop the test lead 3 times through the 428B probe

35、jaws. Switch the 428B to the 3 amp range. The 428B should read 3 amps 90 mA. d. Remove the test lead from the 428B probe jaws and zero set the 428B. Clamp the jaws over the unlooped lead after switching the 428B to the 1 amp range. The 428B should read 1 amp 30 mA. e. Continue to downrange the 428B

36、and the meter calibrator as in Steps c and d and as guided by the Performance Check Test Card. Where possible, keep the calibrator at full output to take advantage of the greater accuracy; this consideration applies to any meter calibrator which is specified at full range (or full-scale) output. Not

37、e that there will be a small residual magnetism induced in the probe by the 10 amps of current that have been passed through the probe, and that it is good practice to degauss the probe before using the 1 mA range. 5-15. METER TRACKING. 5-16. The test arrangement and equipment required for this test

38、 are the same as for Paragraph 5-13. a. Zero the 428B on the 1 mA range. b. Switch the 428B to the 100 mA range. Switch the meter calibrator to the 10 mA range and adjust for 10 mA of output. Connect a long, thin test lead to the output terminals of the meter calibrator and loop the lead ten times t

39、hrough the jaws of the 428B probe. Read 100 mA 3 mA on the 428B. Remove the test lead from the jaws of the probe one loop at a time and check the linearity of the readings. Each reading should be within 3 mA of nominal (e.g. 90 3 mA, 80 3 mA. etc.). 5-17. OUTPUT CALIBRATION. 5-18. A meter calibrator

40、 and a one kilohm resistor are required for this test. a. Switch the 428B and the meter calibrator to the 100 mA range. Connect a test lead between the meter calibrator output leads and clip the 428B probe to the lead. b. Set the meter calibrator to 100 mA output and read full-scale on the 428B. c.

41、Connect a voltmeter to the output jack of the 428B. In parallel with the 1000 ohm resistor. d. The voltmeter should read 0.73 V 10 mV. 5-19. FREQUENCY RESPONSE. 5-20. A 50 ohm resistor and a function generator are required to complete this check. a. Connect a 50 ohm resistor to the high output jack

42、of the function generator. b. Turn the 428B RANGE switch to 100 mA then clip the 428B probe around the resistor lead. c. Set the function generator to: Range: .0001 Function: Square DC Offset: 0 Frequency Dial: 5 d. Upon the first up-scale alternation to the 428B, set the function generator Output L

43、evel control for a full-scale reading on the 428B. e. Connect the vertical input of the oscilloscope to the output jack of the 428B. f.Set the coupling of the oscilloscope input to DC. Set sensitivity and vernier to display variations of the 428B output as a 10 centimeter peak -to-peak signal. g. Se

44、t the function generator to the sine function. h. Slowly raise the frequency of the function generator output using the frequency dial and function switch as necessary to bring the output to 400 Hz. Watch the oscilloscope, looking for the lowest amplitude of peak deflection. i.The peak-to-peak level

45、 of the waveform should not drop below 7 centimeters (-3 dB). Figure 5-3. Range Check. 15 Model 428B 5-21. AC OVERLOAD. 5-22. An oscillator or function generator, a 50 ohm resistor, an ac voltmeter or oscilloscope, and the meter calibrator are required to complete this check (a filament transformer

46、and suitable current limiting resistors can be substituted for the oscillator). a. Set the meter calibrator for 10 mA. With the 428B on the 10 mA range clip the 428B probe onto the lead which connects the calibrator terminals. b. Note the 428B reading. c. Set the function generator to 60 Hz, its out

47、put to generate a 10 mA peak sine wave into a 50 ohm resistor (1 volt peak-to-peak or 0.35 volt rms across a 50 ohm resistor). d. Clip the 428B probe onto BOTH the wire from the meter calibrator and the resistor lead from the function generator (see Figure 5-4). e. The 428B should read within 2% of

48、the reading noted in Step b. Figure 5-4. AC Overload. 5-23. NOISE CHECK. 5-24. A battery operated ac voltmeter and a 1 kilohm resistor are required to complete this check. a. Point probe East and West and rotate about its axis. b. Note peak-to-peak change in meter reading, if it doesnt exceed 0.1 mA

49、 on the 1 m A range, proceed. If the change is excessive, perform Paragraph 5-8. c. Zero the Model 428B on the 1 mA range. d. Connect the output of the 428B to the input of a battery operated 403 B with a 1 kilohm resistor in parallel with the 403B input. e. Section V f.With the 428B on the 1 mA Range check for a maximum of 15 m V reading on the AC Voltmeter. g. Switch the 428B to the 3 mA range. Check for a maximum of 5 m V reading on the AC Voltmeter. h. Switch the 428B to the 10 mA range. Check for a maxi