Sansui AU719 protection relay repair....please help!

Discussion in 'Solid State' started by mcgreg66, Jan 2, 2018.

  1. Beau Geste

    Beau Geste Super Member

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  2. petehall347

    petehall347 the brandy coffee man

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    we are homing in on it ..tr11 is in trouble or a resistor around there . i have other thoughts too .possible shorted capacitor c14 c15 .
     
  3. mcgreg66

    mcgreg66 Member

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    R31 58 Ohm
     
  4. petehall347

    petehall347 the brandy coffee man

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    best test tr11 .
     
  5. mcgreg66

    mcgreg66 Member

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    Solder out and test?
     
  6. petehall347

    petehall347 the brandy coffee man

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    that is best way but i would test in circuit first .
     
  7. mcgreg66

    mcgreg66 Member

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    How I should do testing?!
     
  8. petehall347

    petehall347 the brandy coffee man

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  9. petehall347

    petehall347 the brandy coffee man

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  10. mcgreg66

    mcgreg66 Member

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    TR11 right channel tests like this.....
    B-E 640
    B-C 640
    C-E 1890
    C-B 1990
    E-C 870
    E-B 930
    And TR11 left channel tests nearly exact the same....
    Should be alright? Or not?!
     
  11. petehall347

    petehall347 the brandy coffee man

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    yes at least it isnt shorted .
    its late here so cant concentrate too well right now . if you could test resistors values in that general area in the meantime .
    tr10 tr11 collector voltages are telling us something put cant put my finger on it right now . might be a transistor . give them all a quick in circuit test . pull and test again if any look bad .
     
  12. petehall347

    petehall347 the brandy coffee man

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    quick note you could check resistance between tr10 tr11 collectors .
     
  13. mcgreg66

    mcgreg66 Member

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    Don’t want to keep you up.....
    Just answer if you have time.
    CTr10 - CTr11 56Ohm
    Checked C15 correct 1uf and C14 is 46nF
    I will check transistors and resistors around and compare to left channel

    Good night!
     
  14. petehall347

    petehall347 the brandy coffee man

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    sorry but had to do this ..
     
  15. petehall347

    petehall347 the brandy coffee man

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    p.s not connected to the thread at all ..
     
  16. mcgreg66

    mcgreg66 Member

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    Hey Pete,
    I tested all transistors left and right channel and compared all readings.
    Same with all resistors - they all read the same.
    The only suspect to me was TR10
    TR10 left/right
    BE 816/ -
    BC -/-
    CE 910/ -
    CB 635/650
    EC - / 1300 going up
    EB 630/680

    I pulled it out and tested again - hfe 132 - seems low for me but I don’t have comparison!
    I can try to get recommended substitute KSA1381 or KSC3503
    What do you mean- Worth a try or how to goon?
     
  17. mcgreg66

    mcgreg66 Member

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    What about transistors with testing E to C low but climbing up and up to no reading?!
     
  18. petehall347

    petehall347 the brandy coffee man

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    capacitor in circuit charging up
     
  19. petehall347

    petehall347 the brandy coffee man

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    [QUOTE="What do you mean- Worth a try or how to goon?[/QUOTE]

    lost me there
     
  20. petehall347

    petehall347 the brandy coffee man

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    r17 820 ohms may be open
    c16 might be bad .
     

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