Yamaha CA-610 II delayed relay

Discussion in 'Yamaha' started by lectoid, Jul 14, 2014.

  1. avionic

    avionic " Black Knights " Subscriber

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    Can you measure the voltages around TR572 (ECB) reference to chassis ground ?
     

     

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  2. avionic

    avionic " Black Knights " Subscriber

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    Be extra careful not to short out the leads of TR572.
     
  3. scottyv06

    scottyv06 Member

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    I just want to make sure I do this measurement correctly . so measure emitter to the chassis,collector to chassis, and base to chassis for tr 572?
     
  4. avionic

    avionic " Black Knights " Subscriber

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    Yes. Just clip your black test lead to the metal chassis. And probe with the red test probe. Mini grabbers are highly recommended .
     
  5. scottyv06

    scottyv06 Member

    Messages:
    51
    I am getting about -70v on the emitter to chassis,-70v base to chassis and about -40v collector to chassis
     
  6. avionic

    avionic " Black Knights " Subscriber

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    39,295
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    Have a close look at C584.
     
  7. avionic

    avionic " Black Knights " Subscriber

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    Voltages around TR574.575 and 576 ?
     
  8. scottyv06

    scottyv06 Member

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    I replaced c584,582 and 581 earlier.but it didnt solve the issue
     
  9. scottyv06

    scottyv06 Member

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    574 - base to chassis- 0v, collector to chassis, 9.5v emitter to chassis 0v
    575- base to chassis 0v, collector to chassis -.016v ,emitter to chassis 0v
    576- base to collector 4.83v,collector to chassis 0.16v,emitter to chassis 0v
     

     

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  10. avionic

    avionic " Black Knights " Subscriber

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    39,295
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    How about TR577
     
  11. avionic

    avionic " Black Knights " Subscriber

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    TR576 is suspect.
     
  12. scottyv06

    scottyv06 Member

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    577 b= -.08v c= -1v e= -0.16v
     
  13. avionic

    avionic " Black Knights " Subscriber

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    Is fuse F571 still good ? Verify with ohmmeter.
     
  14. avionic

    avionic " Black Knights " Subscriber

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    I think you have E and B reversed. The base of TR577 should be the same voltage as the collectors of TR575 and 576.
     
  15. scottyv06

    scottyv06 Member

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    yes you are right . I typed that wrong base is 0.16v emitter is 0.8 . I checked f571 it is good.
     
  16. scottyv06

    scottyv06 Member

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    51
    So should I try to swap out tr576? or do you think its something else?
     
  17. scottyv06

    scottyv06 Member

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    I swapped out tr576 . it did not resolve the problem
     

     

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  18. avionic

    avionic " Black Knights " Subscriber

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    TR577 possibly. On C584 make sure the positive lead is connected to chassis ground.
     
  19. scottyv06

    scottyv06 Member

    Messages:
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    swapped out tr577 . no changes .I am not sure what you mean by positve lead to chassis ground . I did check the polarity it appears to be installed properly unless there is a mistake on the board.
     
  20. avionic

    avionic " Black Knights " Subscriber

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    Location:
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    When properly installed. The positive lead of C584 is connected to ground. Silkscreening on the yamaha circuit boards has numerous errors.When replacing caps. I always try to pay attention to the polarity of the old cap. I don't rely on the silkscreen.
     
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