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This scanned manual is well done in that most all the pages except for one is straight and clear- the way I would do them. One page was upside down but that happens. For the money that is charged on this site you get a pretty good deal. Now with complex repairs, I still prefer to us paper manuals which I have to buy at stereomanuals but the one I got here was much less than the $45 he was charging but this is a larger than normal manual for three different units. I am a picky manual user because I have used original manuals from Sony and Teac.
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Very useful service manual, was exactly what i needed.Good quality,reasonable price.Thank you.
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Acurate informations inside the SM and I could repair my old Sansui SC-3330 without any problems. Thanks.
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I used it to repair a NAD 7030, but unfortunately, the 7045 is different !
But documentation was useful.
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Content A4 and A3 format pages. Exactly what I needed to restore my old receiver.
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, figu r e 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.
Model 175A 5-75. Table 5-5 gives troubleshooting aids for locating 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 unbalanced output voltage can usually be traced to an open o r shorted tube heater o r a wrong type tube.
Table 5-5. Troubleshooting the Low-Voltage Supply
~~ ~~ ~~ ~
Symptom High output
Procedure
Effect
Trouble Q461 shorted Q461 good
Disconnect base lead of Q461 from Output remains high printed circuit board. This is the yellow lead which connects to r e a r Voltage drops edge of board adjacent to fan motor Reconnect yellow wire to printed circuit board and short collector of Q464 to emitter.
Voltage drops Output remains low Voltage rises
~
Q464 open Q461 open Q461 good CR465 shorted CR465 good Q463 open o r C466 shorted Q463 and C466 Q464 shorted Q464 good Trouble in +llOV
Low output
Short collector of Q462 to emitter
Remove short from Q462 and measu r e voltage across CR465 Measure voltage across R470
0 volt 6 volts
Within 10 volts of output L e s s than output
Measure voltage from collector of Q464 to emitter +llOV High output Check -100 volt supply output
0 volt approx 10 volts
Normal
Disconnect base lead of Q442 from printed circuit board. This is the white lead which connects to r e a r 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
~~
0 volt
Q443 shorted Q443 good Q444 shorted Q444 good Trouble in + l l O V
Greater than 2 volts
0 volt Greater than 2 volts
Normal Abnormal
Low output
Check -100 volt supply output
Short collector of Q443 to emiiter
Output remains low Voltage r i s e s
I
I
Q441 o r Q442 open Q441 and Q442 good
I
5-14
01526- 2
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