175A - HP Archive

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Section V Paragraphs 5-74 to 5-76 5-74. The cause of excessive output ripple on any of the supplies can be isolated in the following manner. Measure the ripple at the output of the rectifiers of the supply in question. Compare the measurement with the value given on the schematic diagram, figure 5-33. If the ripple is excessive, check the input filter capacitors and bleeder resistors. If the input ripple is normal, the cause is most likelylow gain in the amplifier transistors. Symptom High output Table 5-5. Troubleshooting the Low-Voltage Supply ~~ ~~ ~~ ~ Procedure Disconnect base lead of Q461 from printed circuit board. This is the yellow lead which connects to rear edge of board adjacent to fan motor Reconnect yellow wire to printed circuit board and short collector of Q464 to emitter. Low output Short collector of Q462 to emitter Remove short from Q462 and measure voltage across CR465 Measure voltage across R470 Measure voltage from collector of Q464 to emitter Effect Output remains high Voltage drops Output remains low Trouble Q461 shorted Model <strong>175A</strong> 5-75. Table 5-5 gives troubleshooting aids for lo- cating causes of loss of regulation in each supply. 5-76. The balance between the +6.3 volt and -6.3volt supply outputs and ground is determined by the supply load. The load is a series-parallel arrangement of tube heaters, diagrammed in figure 5-34. An unbal- anced output voltage can usually be traced to an open or shorted tube heater or a wrong type tube. Voltage drops Q461 good Voltage rises ~ 0 volt 6 volts Within 10 volts of output 0 volt approx 10 volts 0 volt Greater than 2 volts 0 volt Greater than 2 volts Q461 Q464 open Q461 open good CR465 shorted CR465 good Q463 open or C466 shorted Less than output Q463 and C466 Q464 shorted Q464 good +llOV High output Check -100 volt supply output Normal Trouble in +llOV Disconnect base lead of Q442 from printed circuit board. This is the white lead which connects to rear edge of board adjacent to fan motor Voltage drops Reconnect white lead and measure voltage from collector of Q443 to emitter Measure voltage from collector of Q444 to emitter Q443 shorted Q443 good Q444 shorted Q444 good ~~ Low output Check -100 volt supply output Normal Trouble in +llOV Abnormal Short collector of Q443 to emiiter Output remains low I Q441 or Q442 open I I Voltage rises Q441 and Q442 good 5-14 01 526- 2
: Model j j I I I ~ 1 <strong>175A</strong> + ll0V cont'd + 370V f 6.3V 01526-1 Symptom Low output High output Low output High output (Voltmeter from + 6.3V to -6.3V output) Table 5 -5. Troubleshooting the Low -Voltage Supply (Cont'd) d which connects of board adjacent to Check -100 volt supply output Section V Table 5-5 (cont'd) rouble in -lOOV 5-15
Page 1: HP Archive This vintage Hewlett Pac
Page 4 and 5: Table of Contents Model 175A Sectio
Page 6 and 7: Section I Figure 1-1 1-0 Figure 1-1
Page 8 and 9: Section I Table 1-1 and Figure 1-2
Page 10 and 11: 1 . Section I Paragraphs 1-9 to 1-1
Page 12 and 13: Section III Model 175A Figure 3-1 p
Page 14 and 15: Section 111 Figure 3-2 1. Set INTEN
Page 16 and 17: Section 111 Model 175A Figure 3-4 @
Page 18 and 19: Section Iv Figure 4-1 Q\ j j iqpm-1
Page 20 and 21: Section IV Paragraphs 4-11 to 4-29
Page 22 and 23: Section IV Paragraphs 4-34 to 4-41
Page 24 and 25: Section IV Paragraphs 4-47to 4-56 V
Page 26 and 27: ! I 5 Section V Table 5-1 - Item -
Page 28 and 29: Section V Paragraphs 5-13 to 5-17 i
Page 30 and 31: Section V Paragraphs 5-21 to 5-32 5
Page 32 and 33: Section V Figure 5-2 5- 6 -R45 GAIN
Page 34 and 35: Section V Paragraphs 5-40 to 5-42 c
Page 36 and 37: Section V Paragraphs 5-47 to 5-50 F
Page 38 and 39: Section V Paragraphs 5-57 to 5-60 m
Page 42 and 43: Section V Paragraphs 5-77 to 5-85 S
Page 44 and 45: Section V Paragraphs 5-93 to 5-100
Page 46 and 47: Section V Table 5-9 (Cont'd) 15. Tr
Page 48 and 49: Section V Model 175A Figure 5-13 3E
Page 50 and 51: Model 175A 01526-2 (u a - R88 In I
Page 52 and 53: I R34 :i554 R36 7 c21 0 c23 C16 C25
Page 54: 2.: h(YN e a E -4 a e f
Page 58 and 59: - 2- a s; - a L C125 R143 R138 t 0
Page 60 and 61: Model 175A , 01526-2 SCHEMATIC DIAG
Page 63 and 64: RlOlO 0 d ncu 0 0 0 0 0 0 0 0 a a a
Page 66 and 67: c22 I " R234 R236 R2d R245 :215 R24
Page 68 and 69: I I? .A N d N v1 .A 0
Page 70 and 71: Section V Figures 5-29 and 5-30 SCH
Page 72 and 73: I I CR483 c482 Ck463 I CR443 1" a46
Page 74 and 75: i C a I -- n I n > N t ij I- A Y D
Page 76 and 77: Section V Figures 5-34 to 5-36 5-38
Page 78 and 79: Model 175A Section VI Paragraphs 6-
Page 80 and 81: Model 175A Section VI Table 6-1 Ref
Page 82 and 83: Model 175A Reference Designation C3
Page 84 and 85: Model 175A CR304 Ck420 CR421 Cli422
Page 86 and 87: Model 175A L105 L106 LZOO L20 1 L20
Page 88 and 89: Model 175A R6O R61 R62 R63 R6Y I365
Page 90 and 91:
Model 175A n177 R178 R179 Rl8O Rl8l
Page 92 and 93:
Model 175A Reference De sienation t
Page 94 and 95:
Model 175A Section VI Table 6-1 Ref
Page 96 and 97:
Model 175A Reference Designation v2
Page 98 and 99:
Model 175A Section VI Table 6-1 Ref
Page 100 and 101:
Model 175A @ Stock No. 0140-0034 01
Page 102 and 103:
I Model175A Section VI Table 6-2 @
Page 104 and 105:
Model 175A @I Stock No. -~ 0773-000
Page 106 and 107:
Model 175A - @ Stock No. 5060-0765
Page 108 and 109:
Model 175A Cod. No. 01216 01413 816
Page 110 and 111:
CRT WARRANTY CLAIM FROM: DATE: NAME
Page 112 and 113:
@ AUTHORIZED SALES AND SERVICE OFFI
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175A - HP Archive

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