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Pioneer SA 8500 loosing channel

Discussion in 'Pioneer Audio' started by lsneon, Jan 7, 2018.

  1. lsneon

    lsneon New Member

    Messages:
    5
    When my SA 8500 warms up, the left channel seems to fade out on
    most inputs. Any suggestions on where to start looking as a likely
    culprit? TIA
    lsneon
     

     

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  2. inductor

    inductor Super Member

    Messages:
    1,576
    Location:
    uk
    speaker relay, dry joints, etc etc
     
  3. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,894
    Location:
    Glen Burnie Md.
    BOTH Channels or just one channel (Left or Right)?
     
  4. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

    Messages:
    21,122
    Location:
    Bensenville,Illinois
    deoxit first anything that goes up n down, in n out or roundy round that has an electrical connection. period.
     
  5. lsneon

    lsneon New Member

    Messages:
    5
    First thing I did was D-5'd anything that moves. I swear by that stuff. I just figured it was an elec cap going bad.
    Thought I'd ask if anyone could point me in a likely direction. It's odd in that sometimes the channel fades after
    2-3 minutes, rt now it's been on 30 min and still have both channels. Also swapped speaker leads and eliminated
    that as a possibility. Thanks to all those that take the time to share their knowledge.
    lsneon
     
  6. Blue Shadow

    Blue Shadow I gotta get me a new title

    Messages:
    21,449
    Location:
    SE PA
    doesn't seem to be the relay but it is so easy to change on an 8500, I'd do that next time you go into the unit. I mean it is right there in the middle of the board and with the top and bottom off, simple.
     

     

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  7. mbz

    mbz Super Member

    Messages:
    2,265
    Location:
    Melbourne, Victoria
    Bias checked, ok it's a long shot, maybe just at that threshold value...
     
  8. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

    Messages:
    21,122
    Location:
    Bensenville,Illinois
    the relay goes up n down....

    use a piece of deoxit wetted card stock between the relay contacts with the relay actuated to clamp the contacts together.
    When it fades, turn it to mono and see if that does anything - because the mono switch is ALMOST the last one in line for total signal cessation.

    Lo-filt can, hi-filt cannot. Interupt all audio on a channel.

    then it's pre-out and amp in, and there's a funny thing with that - deoxit the jumpers as well. I HAVE seen it happen!!!

    After that - then get a pair of interconnects, and swap l/r at teh pre-out / amp in jacks - and see if the fading stays put.
    stay put is power amp, move is preamp.

    If it's the power amp - remember the amp circuit is chock full of troublemakers - 2sa726's and 2sc1451's.
     

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