SX-636 Repair Help

Discussion in 'Pioneer Audio' started by revision-88, Jan 10, 2019 at 7:07 PM.

  1. avionic

    avionic " Black Knights " Subscriber

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    45,470
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    Good..Can you post a photo of your main filter caps? Both topside and bottom side?
     

     

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  2. revision-88

    revision-88 New Member

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    Of course. 6800uF 50v Nichivons. I thought I wired them in correctly. 20190111_201422.jpg 20190111_201458.jpg
     
  3. avionic

    avionic " Black Knights " Subscriber

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    45,470
    Location:
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    Are you seeing -41vdc on pin 10 of the AWR-060 power supply board?
     
  4. revision-88

    revision-88 New Member

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    19
    I'm seeing -47v there.
     
  5. avionic

    avionic " Black Knights " Subscriber

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    45,470
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    Looks OK. And your getting +/- 30volts DC at the collectors of the outputs.
     
  6. avionic

    avionic " Black Knights " Subscriber

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    45,470
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    Super..
     

     

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  7. revision-88

    revision-88 New Member

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    +33 at Q11/12, -33 at Q13/14.
     
  8. avionic

    avionic " Black Knights " Subscriber

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    45,470
    Location:
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    Are the two STV3 diodes still intact ( no broken leads)?
     
  9. avionic

    avionic " Black Knights " Subscriber

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    45,470
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    Close enough.
     
  10. revision-88

    revision-88 New Member

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    They all look good to me.
     
  11. avionic

    avionic " Black Knights " Subscriber

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    45,470
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    For some reason those STV diodes are prone to breakage of the leads. Thats why I asked.
     

     

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  12. revision-88

    revision-88 New Member

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    The red and white ones on the power amp board, right? Those and all the other diodes in the amp look fine.
     
  13. avionic

    avionic " Black Knights " Subscriber

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    45,470
    Location:
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    Have you tested Q5-Q10 out of circuit?
     
  14. revision-88

    revision-88 New Member

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    I have not yet, I'll pull and test them when I have a chance.
     
  15. avionic

    avionic " Black Knights " Subscriber

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    45,470
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    ? Usually there black or tan in color. Horseshoe shaped. And fastened to the large to the heatsink.
     
  16. revision-88

    revision-88 New Member

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    I don't see anything matching that description on any of the boards.
     

     

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  17. avionic

    avionic " Black Knights " Subscriber

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    upload_2019-1-11_21-21-28.jpeg



    D5 and D6 Soldered to the amplifier board and screw mounted to the heatsink.
     
  18. revision-88

    revision-88 New Member

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    19
    Ah thanks. Found them. The leads look just fine to me.
     
  19. avionic

    avionic " Black Knights " Subscriber

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    45,470
    Location:
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    Happy hunting. I have no more suggestions until we know the condition of all the transistors on the amplifier board.
     
  20. revision-88

    revision-88 New Member

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    19
    No problem, thanks for all the help. Fortunately there's not too many of them so I'll post here as soon as I have new info.
     

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