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

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

  1. mcgreg66

    mcgreg66 Member

    Messages:
    80
    R17 is 811Ohm
    But C16 is 415 dropping under 400

    You think TR10 is ok?
     

     

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  2. mcgreg66

    mcgreg66 Member

    Messages:
    80
    Goes down to 380uF
     
  3. petehall347

    petehall347 the brandy coffee man Subscriber

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    try a new cap
     
  4. mcgreg66

    mcgreg66 Member

    Messages:
    80
    Hey Pete,
    Installed a new C16 470uf cap.....(from local store / just right within tolerance 415uf)
    Tried to set DC and Bias
    Right channel DC semms to be more stable but still incredibly hard to adjust and then jumping over 40mV
    Still no bias !
    Relay starts clicking after powered on for 5-10min but doesn’t stay engaged.

    Thanks
    Gregor
     
  5. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
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    the trimmer may need replacing for a new one
     
  6. mcgreg66

    mcgreg66 Member

    Messages:
    80
    I just wanted to say....
    .....maybe the trim pot is bad.
    I gave a little tunerspray ......and there is correct bias.
    DC still hard to adjust and fluctuating, but only a few mV and nearly within spec.
    But relay only clicking.......
     

     

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  7. petehall347

    petehall347 the brandy coffee man Subscriber

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    get tr603 voltages .protect circuit .
     
  8. mcgreg66

    mcgreg66 Member

    Messages:
    80
    TR603
    E 0v
    C 38,8v
    B 0,47-0,6v
     
  9. petehall347

    petehall347 the brandy coffee man Subscriber

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    so the base is shifting around ?
    suggest changing c603 .
    but before that lets see all pin voltages of protect circuit first to see if something amiss there .
    tr603 cant be ruled out yet .
    i seem to remember c601 causing this problem a long time back .
     
  10. mcgreg66

    mcgreg66 Member

    Messages:
    80
    Yes Base TR603 is shifting around 0,47-0,6v

    Pin voltages F-3101
    01 -80-+80mv
    02 -80-+80mv
    03 -80-+80mv
    04 -80-+80mv
    06 -90-+90mv
    07 -90-+90mv
    08 -90-+90mv
    09 +55,5v
    10 +56v
    11 -55,5v
    12 -56v
    13 0
    14 0
    15 +32,5v
    16 0
    17 -32,5v
    18 +42-44,5v
    19 0
    21 +3-7mv
    22 -12mv
    23 0
    24 0
    25 14-28v
    26 14-28v
    27 0
    28 0
     
  11. mcgreg66

    mcgreg66 Member

    Messages:
    80
    I ordered a few KSA945C and will change TR601 and 603
     

     

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  12. mcgreg66

    mcgreg66 Member

    Messages:
    80
    Hi Pete,
    Still need you advice!
    I changed TR601 + TR603 and c603
    ......but still protection mode.
     
  13. petehall347

    petehall347 the brandy coffee man Subscriber

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    tr603 base ?
    tr602 collector
    are those steady voltages now ?
     
  14. mcgreg66

    mcgreg66 Member

    Messages:
    80
    TR603
    E 0
    C 32,5-38v
    B 560-600mV

    TR602
    E 0
    C 6,5v
    B jumping -20-120mV

    But even again no bias at right channel!
    I’ll wait for the trim pots and change them first!
    If the channels are not stable it makes no sense to work on the protector! Right?!
     
  15. petehall347

    petehall347 the brandy coffee man Subscriber

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    Location:
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    try lifting one end of d606 and see what happens .. just want to rule something out . also check all soldered joints .
    there is a chance of zd601 being bad .
     
  16. mcgreg66

    mcgreg66 Member

    Messages:
    80
    Lifted anode of d606 and powered on ..... still protection!
     

     

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  17. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
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    am thinking change the other capacitors and then see
     
  18. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    This
    Should be 1.6V

    And this
    Should be ~3.7V

    Should be investigated I think.:idea:
     
  19. mcgreg66

    mcgreg66 Member

    Messages:
    80
    I’m expecting a mouser order with all electrolytic caps and known citical parts within the next days.
    For example the big 470uf on PSU/protector board look bad become of infamous Sansui glue.
    Maybe they are leaking !

    Hi John,
    Yes that’s way too much.....
    25 + 26 going to led 01
    18 to head amp
    What do you suggest to do?
     
  20. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Check the readings. ;)
     

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