HP-Service-Note-175A-x 电路图.pdf

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1、HP Archive This vintage Hewlett Packard document was preserved and distributed by vvwvv. h parc Please visit us on the web ! Scanned by on-line curator: Tony Gerbic * For FREE Distribution Only * RadioFans.CN 收音机爱 好者资料库 I - I 175A-1A ? MODEL 175A OSCILLOSCOPE SWEEP AND GATE OUTPUT MODIFICATION KIT S

2、tock No. 175A-95A The Stock No. 175A-95A Modification Kit, when added to the Model 175A Oscilloscope, provides the sweep and gate voltages at the rear panel of the instrument. These outputs may be used to sweep or synchronize external equipment or circuits with the oscilloscope. The SWEEP OUTPUT vol

3、tage provided is approxi- mately 5 volts in amplitude and is centered about 0 volts. The GATE OUTPUT voltage is approximately 4 volts in amplitude and is riding a -2.5 volt level. The Modification Kit is complete with all necessary components, wire, and hardware. You can install the kit with simple

4、hand tools. Holes for mounting the few components are already provided in the instru- ments. INSTALLATION PROCEDURE 1. Remove the horizontal plug-in, top, bottom, and left side covers. 2. Prefabricate coax cables and wires to etched circuit board 175A-655 supplied with kit. Use 24” yellow-white for

5、#1, and 9” yellow-white for #2. (See figure 1.) 3. Install the etched circuit board on left side frame adjacent to the low voltage power supply fuses (see figures 2 and 3). Align board holes with existing holes in side frame. Install board with hardwareas shown. 4. Dress leads as shown in figure 3.

6、PARTS SUPPLIED 175A-95A KIT Quantity 1 1 1 2 2 2 2 2 1 1 1 1 1 Description Etched circuit board . Cable, coax. . Connector, RF, UG-l094/U, female BNC . Cable, coax. . Washer, #6, external lock . Screws, flat head, 6-32 x 1/2 inch Nut, hex w/lockwasher, 6-32 . Washer, #6, flat . . Wire, 22 gauge stra

7、nded, black, 2-1/2 inch length . Wire, 22 gauge stranded, brown, 4 inch length . Wire, 22 gauge stranded, gray, 3 inch length . Wire, 22 gauge stranded, yellow-white, 9 inch length. . Wire, 22 gauge, stranded, yellow-white, 24 inch length . Stock No. 175A- 65 J 175A- 16s 175A-16T 1250-0083 2 190-000

8、8 23 70-0003 242 0-0001 3 05 0-0016 815 0-0005 8150-0007 8150-0027 8150-0040 8150-0040 4/63 RadioFans.CN 收音机爱 好者资料库 Page 2 MODEL l7SA SIDE FRAME 175A-1A LONG SHORT YELLOW -WH # I 175A-65 J *2 Y ELLOW-WHITE 17% - LO-S - I - CS Figure 1. Description and Position of Wires on 175A-65J Board 6-32 HEX NUT

9、 6 FLAT WASHER 6 EXTERNAL WITH LOCK LDCK WASHER WASHER HEAD :W q S l D E FRAME cobx SHIELDS IT5A-W-S-2-CS Figure 2. Mounting Position and Sequence of Etched Circuit Board, 175A-655 PIN 01 POWER TRANSFORMER HOLE IN CHASSIS )AM COVERED SWEE UTPUT LEAD TO MOR lllP CONNECTS MERE ACCf53 coll MOMZONTAL PL

10、UQ-IN UNIT. 8nb.LO.L.I.Cl 421 $AMP GAMP 441 481 AMP -010 46 1 LAMP L*CK Figure 3. Component Location - Bottom View, Rear H a l f of Oscilloscope 015 84-2 RadioFans.CN 收音机爱 好者资料库 175A- 1A 5. Connect and solder the shortest co xi 1 1 d 13. Conn (coax #2 on figure 1) to pin 1 of the horizontal plug-in

11、BNC. connector, 5105. I 6. Connect and solder the 9 inch yellow-white lead (marked #2 on figure 1) to pin 17 of the horizontal plug-in connector, 5105. 7. Connect and solder the gray lead to the -6.3 volt take-off point on the etched circuit board mounted at right angles and adjacent to the fuses. U

12、se the existing vacant hole. 8. Connect and solder the brown lead to the +6.3 volt take-off point. 9. Connect and solder the black lead to the end of the - 100 volt fuseholder nearest the chassis. Another black wire is already soldered to this point. 10. Dress the longest coaxial lead (coax #1) and

13、24 inch yellow-white lead (#1) from the hole in the chassis to the sweep and gate output holes in the rear gusset. 11. Remove plug buttons from the SWEEP and GATE OUTPUT holes. 12. Install the two BNC connectors in these holes. Page 3 ct and solder coax #1 to the GATE OUTPUT 14. Connect and solder y

14、ellow-white lead (#1) to the SWEEP OUTPUT BNC. 15. Install the horizontal plug-in. CAUTION Dress components on the newly installed etched circuit board to clear the plug-in when installing. 16. Install the left side, top, and bottom covers. This completes the modification. Calibration is not affecte

15、d. OPERATION CHECK Turn the instrument on and set the SWEEP MODE control to FREE RUN, Check the sweep and gate out- puts for agreement with the specifications listed in the Model 175A Operating and Service Manual. 01584-1 hp Model 175A Oscilloscope Serials Below 326-01376 Thermal Switch Assembly Mod

16、ification Kit hp Stock NO. 175A-95E This Service Note obsoletes Service Note 175A-2 Installation of Thermal Switch Assembly Modification Kit, hp Stock No. 175A-95E, in hp Model 175A Oscilloscope, serials below 326-01376, will provide component protection from damage due to excessive temperatures. Th

17、e thermal switch will turn off the oscilloscope if the fan fails and the instrument starts to overheat. Cutoff temperature can be controlled over a range of a few degrees by positioning of the series regulator shunt resistor in relation to the thermal switch. A new shunt resistor is provided in the

18、kit and is mounted on the thermal switch support bracket. Installation of the Thermal Switch Assembly Kit involves some com- ponent and wiring changes. It also requires drilling of two small holes in the oscilloscope main frame. Except for a hand drill, special tools are not required. After completi

19、ng the installation, an operating check of your oscilloscope should be made, but calibration or adjustment is not r equ ired . Material Furnished in hp 175A-95E Kit 99 1 1 1 1 Description hp Stock No. Thermal Switch Assembly 175A-19H Cable 175A-16AC Terminal Board, two tie- 0360-0015 Terminal Board,

20、 right-hand 0360-0014 points and ground tiepoint and ground Wire, 6 inch, white, 18 gauge 8150-0081 1168-8 1900 Garden of the Gods Road, Colorado Springs, Colorado, U.S.A. ref. (303) 636-5111 Europe: 54 Route Des Acacias, Geneva, Switzerland, Cable: HEWPACKSA Tel. (022) 42.81.50 I Page 2 4 2 3 175A-

21、2A Material Furnished in hp 175A-95E Kit (contd) Description hp Stock No. Wire, 6 inch, slate, 18 gauge 8150-0087 Round Heat, 3/8 long lockwas her Machine Screw, #6-32, SS, 2360-0005 Nut, Hex, with external 2420-0001 Lockwasher, external #6 2190-0007 INSTALLATION PROCEDURE 1. The 2.3 ohm, 45 watt re

22、sistor located on the bracket of Thermal Switch Assembly, stock no. 175A-l9H, is a replacement for R482. Position this resistor 1/16 - 1/8 inch below the thermal switch and rotate its terminals to the rear (away from the neon lamp) and tighten its mounting screws. 2. Connect and solder the 6 inch wh

23、ite wire to one terminal and the 6 inch slate wire to the other terminal. 3. Place the Model 175A Oscilloscope upside-down. Remove the screws that secure the Low Voltage Power Supply Board (175A-65D). 4. Remove the white, blue, and black leads by removing the edge-on connectors from the front edge o

24、f the board. 5. expose the electrolytic capacitors. Lay back the board toward the rear of the instrument to fully 6. Without disconnecting any leads, remove and lay back the three capacitors nearest L481. These capacitors are C441, C442, and C443, 7. Notice that the capacitor mounting bracket ends b

25、efore reaching the inductor L481. this mounting bracket and about 3/8 from L481. (About halfway be- tween L481 and the edge of the mounting bracket) Center-punch a mark in line with the center of 8. the capacitor mounting bracket. Center-punch another mark 3-1/8 from the first and centered on Page 3

26、 9. 10 0 beh D r i l l the holes with a $120 d r i l l . Install the thermal switch assembly on the top ,nd the vertical plug-in slot, and positioned w forward. Use the hardware provided. 175A-2A of the main deck t h the neon bulb 11. Replace the electrolytic capacitors and the low voltage power sup

27、ply boar do 12. Reconnect the white, blue, and black leads t o front edge o f board. 13. Locate, remove and discard the old R482. It may be found t o the right and rear of the newly installed thermal assembly. attached wires close t o the resistor terminals. Cut the 14. Install the terminal s t r i

28、p with the two tiepoints and ground in place of resistor R482. lockwasher. Use one of the #6-32 screws and an external 15. Solder the white lead from the new R482 and three white leads removed in step 13 t o one of the tiepoints. 16. Solder the gray lead from the new R482 and the gray leads re- move

29、d in step 13 t o the other tiepoint. (The ground lug is not used at this t i m e . ) 17. Strip the leads and feed the shielded cable through the chassis hole located forward of Diodes CR481 and CR482. Note The end of the cable having the longest ex- posed leads should be on the bottom side a the osc

30、illoscope, and w i l l connect t o the fuseholder. 18. Remove the protective cover from the top of the terminal switch as s emb 1 yo 19. The exposed terminals are marked 1, 2, and 3. Terminal 2 has a white w i r e connected t o it. Page 4 175A-2A 19. (contd) a. Connect and solder the black conductor

31、 t o terminal 1. b. Connect and solder the white conductor t o terminal 3. (The neon is attached here.) c. Connect and solder the black shield w i r e t o the center tie- point on the terminal s t r i p . 20. Recheck solder connections and replace protective cover. 21. Route the shielded cable along

32、 the bottom of the chassis t o the line fuseholder. 22. Mount the terminal board, stock no. 0360-0014, with the conven- ient chassis screw located forward of rear panel. 23. Connect and solder the black shield w i r e t o the ground terminal. 24. Connect the white conductor t o the tiepoint. 25. Rem

33、ove the black lead from the side terminal of the fuseholder and connect it t o the tiepoint with the white conductor (step 24). Solder connections. 26. Connect and solder black conductor from shielded cable t o the side terminal of the fuseholder. OPERATIONAL CHECK A n operational check of your Mode

34、l 175A Oscilloscope completes the procedure . OS I SERVICE NOTE APRIL 1965 MODEL 175A OSCILLOSCOPE Serials Below 413-02326 Modification of 175A for 1784A Recorder Plug-in This modification is necessary if the 1784A Recorder plug-in is to be used with these 175A Oscilloscopes. The installation of a t

35、wisted pair of wires between the power transformer and the horizontal plug-in jack provides the 115VAC necessary for the operation of the 1784A Recorder Plug-in. Two 1 1 long #22 (1 kv) wires are required, they should be wht/gry and wht/blk/ gry in color. 4 Modification Procedure 1. Remove bottom co

36、ver of 175A. 2. Connect the twisted pair of 11 long #22 (1 kv) wire from terminals 10 and 12 of transformer T401 to terminals 30 and 31 of 5105 such that the wht/gry wire connects transformer terminal 12 and terminal 31 of 5105. This modification requires no recalibration or additions to the Replace

37、able Parts List. 02521-1 8 7900 Garden of the Gods Road, Colorado Springs, Colorado, U.S.A. Tel. (303) 636-5777 Europe: 54 Route Des Acacias, Geneva, Switzerland, Cable: HEWPA CKSA Tel. (022) 42.87.50 CRINTLB IN U.S.A. I rl I I OSCILLOSCOPE 175A-6 MODEL 175A OSCILLOSCOPE Serial Prefix Below 450- New

38、 Vertical Output Printed Circuit Board 175A-65W The 175A-65W is a direct replacement for the 175A-65T. Add the 175A-65W to the Replaceable Parts List in your 175A Operating and Service Manual. Recalibration of the vertical amplifiers will be necessary after the installation of this Printed Circuit B

39、oard. See Paragraphs 5-53 thru 5-57 of your Operating and Service Manual. 02522-1 8 PRINTLO IN U.S.A. 1900 Garden of the Gods Road, Colorado Springs, Colorado, U.S.A. Te/. (303) 636-5111 3 Europe: 54 Route Des Acacias, Geneva, Switzerland, Cable: HEWPACKSA Tel. (022) 42.81.50 1 SERVICE NOTE APRIL 19

40、65 MODEL 175A OSCILLOSCOPE All Serials Improved Sweep Operation For improved sweep operation in the175A Oscilloscope V106 should be a 6CL6 (1923-0066). Change the stock number in the Replaceable Parts List from 1923-0030 to 1923-0066. This is a special 6CL6. I 02523-1 8 CRINTLD IN U . S . A . 1900 e

41、arden of the Qods Road, Colorado Springs, Colorado, U.S.A. Tel. (303) 636-5111 0 Europe: 54 Route Des Acacias, Geneva,Switzerland, Cable: HEWPACKSA Tel. (022) 42.81.50 I r , . . I , Il”r I - .- 1 HEWLETT P A C K A R D I Lei I MODEL 175A OSCILLOSCOPE Serial Prefixes Below 436- INCREASED VERTICAL DC S

42、TABILITY The DC stability of the main vertical amplifier in the above instruments may be improved by installing the Part No. 175A-65V input amplifier circuit board. This modification eliminates the small amount of trace drift that occurs over a period of one or two minutes after a DC voltage step is

43、 applied to the vertical input. This is the only advantage of the new board so the modification is worthwhile only if the slight drift poses a problem. The new board is a direct replacement and no special tools are needed for the modification. Recalibration is necessary after completing the modi- f

44、ication Note The Model 1750A Dual Trace Vertical Amplifier has the same type of drift as above. This modificationwill eliminate the drift caused by the 175A. To elimi- nate the drift caused by the 17504 it should be operated with the vernier turned fully ccw. Ckt Ref CHANGE: A1 L13 R15 DELETE: C7, C

45、8 L7, L8 R16 R19, R20 R23, R24 R21, R22 * ADD: C12, C13 c53 c54 Q1, Q2 R1 R2 R27, R28 R29 R98 R99, RlOO R10 1 R.102, R103 *Refer to Finure 1. Parts Required Resistor: 1K ohms, 5%, 1/2W Vertical Input Assembly MODIFICATION PROCEDURE 1. Remove top cover. 2. Replace Vertical Input Assembly A1 with new

46、175A-65V board. All connections remain the same. 3. Replace R46 on circuit board A2 with 1K ohms resistor. Recalibrate the vertical amplifier as described inthe Model 175A Operating and Service Manual except for the Adjustment Procedure change as follows: In the Hi Freq Response step of the Pulse Re

47、sponse Adjust- ment paragraph in the Maintenance Section of your Operating and Service Manual, substitute C53 for L7 and L8. REVISION TO TABLE OF REPLACEABLE PARTS De sc rip t ion TO: Assy: vertical input Coil: fxd, rf, .68 ph R: fxd, metal oxide, 750 ohms, 2%, 2W R: fxd, comp, 330 ohms, 5%, 1/4W C:

48、 fxd, cer, 0.05 pf, 20% 400VDCW Coil: var, rf R: fxd, comp, 1. 5K, 1%, 1/2W R: fxd, comp, 68 ohms, 576, 1/4W R: fxd, metal film, 6. 5K, 5%, 3W C: fxd, cer, 1000 pf, 6OOVDCW C: var, cer, 5-25 pf C: fxd, mica, 30 pf, 5%, 500VDCW Transistor: 2N708 R: fxd, comp, 120 ohms, lo%, 1/4W R: fxd, comp, 6.8K, 576, 1/4W R: fxd, comp, 1. 5K, lo%, 1/2W R: fxd, comp,