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PM50 Marantz amplifier schematic diagram

chris000 Posted messages 1 Status Member -  
willou-78 Posted messages 68 Status Member -
Hello everyone, I own a Marantz PM50 amplifier, and I have a problem with a fault regarding an internal circuit breaker that cuts off one of the two output channels. I would like to get the schematics for this amplifier if anyone has them. Thank you all and have a good day.

10 answers

  1. Daviken
     
    Good evening,

    STK3062IV replaced by STK3082III, power supply switched to 240 volts. Everything works perfectly except for my left channel issue on speaker series 1. Otherwise, I do have both left and right channels on the second output (speaker 2). I will disassemble it and probably change the corresponding relay.

    Daviken
    1
  2. 3x
     
    Hello.
    I doubt you’ll find that.
    A Marantz should be repaired by a pro, don’t hesitate to get multiple quotes especially!
    --
    *** Hard to find the info! ***
    *** Helping you is a pleasure that should remain so ***
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  3. jow
     
    Hi, to avoid this problem, you need to use a compressed air can inside the amp. You open the top part, spray a little bit everywhere, and let it run for a little hour at medium volume, just to see if it still crackles. If not, it’s fixed ^^

    Have Fun
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  4. top-fet Posted messages 2 Status Member
     
    Owner of a magnificent PM 50 from Marantz, I'm missing frequencies in the high end of the spectrum. If anyone has a tip to fix this issue, that would be nice.
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    1. willou-78
       
      Hello,

      for the problem of lacking high frequencies, I will also use a compressed air can.

      These old amps collect dust, which gets into the moving parts such as the volume potentiometer, balance, treble, bass...
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  6. Daviken
     
    Hello,

    If you are still looking for the plan, I can provide it to you. Probably one of the two relays is defective or stuck.

    Best regards
    0
    1. milor35
       
      Hello
      I have a problem with my PM-50 amplifier (no sound output)
      and I am looking for technical documentation
      maybe it's also due to the STK?
      0
    3. Daviken
       
      Good evening,

      Yes, I have the complete technical documentation. I can make it available to you.
      For the malfunction, check that the relays are not stuck.

      Daviken
      0
    4. willou-78 Posted messages 68 Status Member 3
       
      The technical notice is online, in my link just above otherwise :)
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  7. William
     
    re,
    the recurring problem with the PM50 is the 15-pin preamp module. The STK3062 that eventually fails due to the voltage increase in our households, which has gone from 220 to 230, even 235 Volts.

    Solutions:
    - replace the 3062 with a 3082, which can handle higher voltages
    - modify the input wiring of the transformer from 220 to 240V

    The 3 I repaired had the same failure ;)

    it costs less than 15€
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  8. Daviken
     
    Good evening,

    Yes, I read online that the STK3062 was frequently the issue and that it could be favorably replaced by an STK3082.
    In my case, the left channel does not work on the first set of speakers. However, on the second set, both channels work correctly. I just got this amplifier, and I will let it run for a while to check if there are any other problems.

    Best regards
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  9. willou-78
     
    Good evening,

    oh yes, so it's the output B that isn't working? It must just be a relay problem then.....

    Good luck
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  10. Daviken
     
    Hello,

    Given the reliability of the STK3062, I just ordered a STK3082III (€13.00 including shipping) to replace it. At the same time, when replacing it, I will switch the power supply to 240 volts.

    Best regards
    0
  11. willou-78 Posted messages 68 Status Member 3
     
    It might be a resistor or the relay mechanism itself that is "stuck" ;)
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