Technics SA-5070 no left speaker channel

Discussion in 'Solid State' started by luaplerog, Jan 2, 2019.

  1. Eastham

    Eastham More Class-A than ever!

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    Pins 4 and 13 should have -23.1v and pins 6 and 11 should have -25, sure they're not present?
     

     

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  2. luaplerog

    luaplerog Member

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    77
    yep, that's what i'm getting...def. something wrong. :(
     
  3. Eastham

    Eastham More Class-A than ever!

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    Location:
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    Check your solder joints make sure they're making good connection.
     
  4. sregor

    sregor AK Subscriber Subscriber

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    pin 9 should be +25, pin 8 +24. Pin 10 is right channel out, which (if I read this thread right) is the good channel. Turn volume all the way down. The supply voltages 9, 6 and 11 are inconsistent with anything working.
     
  5. Ylli

    Ylli Member

    Messages:
    55
    Make sure your voltmeter is working. Try measuring a 9 volt battery.
    Be sure you have a good ground for the negative lead of the voltmeter. Either speaker (-) output points would be a good ground. Somethines trying to use the chassis can be problematic.
    Turn the unit on, with the volume turned all the way down. It is not necessary to have the speakers connected. *Carefully* probe each pin of the amplifier device being careful not to short between adjacent points.
     
  6. luaplerog

    luaplerog Member

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    77
    All I'm getting is a hum from the left channel...
    I tried probing each pin and those were the numbers I got. :(
     

     

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  7. Ylli

    Ylli Member

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    Does your voltmeter work? Are you sure you are probing the correct points? It is not possible to get *any* audio output from either channel without voltages present at some of those pins.
     
  8. luaplerog

    luaplerog Member

    Messages:
    77
    yes the voltmeter works and yes I was probing the right pins. I'll try again tomorrow I guess...
     
  9. luaplerog

    luaplerog Member

    Messages:
    77
    I'm giving up on this. The left channel burned up my speaker. The woofer started smoking so now I need to replace the woofer. :(
     

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