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fisher receiver weak left channel...

Discussion in 'DIY' started by dowey, Apr 2, 2009.

  1. dowey

    dowey Well-Known Member

    Messages:
    513
    Location:
    graham nc
    picked up a silver faced fisher receiver today model no 143? says sears audio by fisher, all lights controls etc work but the left channel is weak, opened it up and looked at all the circuit boards found one resistor that looks suspect(kindve burnt and black in the middle) has the fisher hybrid ic pa 501 power modules, i cleaned all the switches and pots(no static) so if replacing the burnt resistor does not fix the left channel any ideas? i measured the dc offset and got 9.5 to 10.9 in the left channel and 44.5 to 48.5 in the right... ill try to post a picture later thanks for your help!
     
  2. Fred Longworth

    Fred Longworth audio fanatic

    Messages:
    3,473
    Location:
    San Diego
    The PA501's have a very high failure rate, now that they are old.

    By the way, was that 9.5 millivolts or 9.5 volts???

    Fred
     
  3. dowey

    dowey Well-Known Member

    Messages:
    513
    Location:
    graham nc
    millivolts, the left channel comes in, it doesnt nearly have the volume of the right, replacing the resistor did not help do you know where i could get a replacement for the amplifier modules? thanks so much for your reply! oh one other thng it has only one big filter cap never seen an amp like that.. thanks,
    chad
     
  4. tcdriver

    tcdriver AK Subscriber Subscriber

    Messages:
    4,527
    Location:
    Valley of Heart's Delight
    I do not know if this will be any help; my fisher receiver uses a PA500 which is a Sanyo STK032.
     
  5. Fred Longworth

    Fred Longworth audio fanatic

    Messages:
    3,473
    Location:
    San Diego
    If the hybrid power amp module doesn't fix it, then I strongly suspect an electrolytic capacitor in the signal path.

    * * * * *

    I am of course assuming that you've cleaned the switches and controls with Caig DeoxIT.

    Fred
     
  6. dowey

    dowey Well-Known Member

    Messages:
    513
    Location:
    graham nc
    thanks !mine uses a pa 501 wonder what the equivalent would be?
     
  7. dowey

    dowey Well-Known Member

    Messages:
    513
    Location:
    graham nc
    i deoxed all the switches and pots, would you happen to know the equivalent of the pa 501? im assuming its a stk something?
     
  8. hamrules

    hamrules Member

    Messages:
    56
    Location:
    Milwaukeee Area
    Might be a STK082 or STK083.
     
  9. dowey

    dowey Well-Known Member

    Messages:
    513
    Location:
    graham nc
    any idea where i could get those?
     
  10. hamrules

    hamrules Member

    Messages:
    56
    Location:
    Milwaukeee Area
    Unable to verivfy this PA501 to STK082 for sure it just shows in some interchange for transistors. The STK082 is rated for 35 watts @ 8 Ohms if that helps at all. Also if it is correct it interchanges to a NTE1327 on their site and as of right now there happens to be a lot of 2pcs of the NTE1327 up on eBay for a really good price. No, I have nothing to do with this auction just doing some reasearch on your question / problem.
     
  11. dowey

    dowey Well-Known Member

    Messages:
    513
    Location:
    graham nc
    thanks alot man im new to all this and really appreciate the help,this will be my second receiver ive repaired,my first was a pioneer sx 780 so im really encouraged thanks again!
    chad
     
  12. Chris Reed

    Chris Reed New Member

    Messages:
    3
    Location:
    Sarasota Fl
    Hi, im also working on the same system, I'm in need of the Fisher PA501 Hybrid-IC did you ever figure out witch STK worked for a replacement ?
     

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