CR-2040 pop when turned off ONLY, not on turn on.

Discussion in 'Yamaha' started by mr_light, Jan 8, 2013.

  1. mr_light

    mr_light AK Subscriber Subscriber

    Messages:
    322
    Location:
    Silver Spring, MD
    I have a CR-2040 that pops when turned off ONLY, not on turn on. Otherwise works perfectly.

    I started this discussion in another existing thread with somewhat similar symptoms, but it's just causing confusion there so I have created my own thread to try to separate the discussions.

    Things I have checked/adjusted:

    Speaker protection relay delays for 3-4 seconds and then clicks (connecting the speakers)
    +60 volt pin on one of the power amps and adjusted to 60 volts +/-1mV
    Adjusted idle current to 10mV +/-1mV
    Adjusted DC offset to 0 volts +/-1mV
    Cleaned and lubed all pots (doubt that is related)
    Inspected components looking for leaking/bulging caps or anything else obvious...

    What else should I check?
     

     

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  2. avionic

    avionic " Black Knights " Subscriber

    Messages:
    41,590
    Location:
    Fort Dodge, Iowa
    Both speakers pop?
     
  3. mr_light

    mr_light AK Subscriber Subscriber

    Messages:
    322
    Location:
    Silver Spring, MD
    It has blown two sets of 1 amp fuses on both of my "good" test speakers. Apparently the pop exceeds 1 amp every time on both channels. I now only have junk speakers attached.

    I should mention I have a fully functional CR-2040 I can test for comparison purposes.
     
  4. avionic

    avionic " Black Knights " Subscriber

    Messages:
    41,590
    Location:
    Fort Dodge, Iowa
    :scratch2:..Might have a real close look at that relay...ie burnt/welded contacts...Is there a arc arrestor across the power switch?Should be..:scratch2:
     
  5. mr_light

    mr_light AK Subscriber Subscriber

    Messages:
    322
    Location:
    Silver Spring, MD
    How to open relay to examine? Also might a speaker relay from a CR-840 work as a substitute (I have a couple of CR-840 donors). There is a spark arrester on the power switch (do they go bad?).
     
  6. 4seatPilot

    4seatPilot "Broker"

    Messages:
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    Location:
    London, Ontario
    You have 840 parts donors? Hmm. Any chance you'd sell me a part or two?


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  7. mr_light

    mr_light AK Subscriber Subscriber

    Messages:
    322
    Location:
    Silver Spring, MD
    Send me a PM with what you need and I'll see what I can do. Never mailed international, but I guess I can figure it out.
     
  8. mr_light

    mr_light AK Subscriber Subscriber

    Messages:
    322
    Location:
    Silver Spring, MD
    Since the relay is open at turn on for the first few seconds I assume the contacts can't be stuck closed. I'm not sure how the timeing for when they open at shutdown is determined and how this protects the speakers. I did confirm that I have a spare identical relay from the CR-840 that I could swap in if needed.
     
  9. formuladale

    formuladale Active Member

    Messages:
    140
    Location:
    The shores of lake erie
    I had the same problem. Shut down it would make a poping sound from both speakers. But on start up relay would click in after maybe 7 seconds and receiver would come on. This went on for approx 6 months. Now as soon as I put receiver on receiver comes on with no delay appears relay has stuck in the closed position. I was told not to use it untill repairs are made otherwise further damage can happen. I hope this helps Regards Dale
     
  10. avionic

    avionic " Black Knights " Subscriber

    Messages:
    41,590
    Location:
    Fort Dodge, Iowa
    Does it POP with the coupler switch (rear panel) in the decoupled or seperated position?
     
  11. 4seatPilot

    4seatPilot "Broker"

    Messages:
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    Location:
    London, Ontario
    Cool... Well do. I have Michigan addresses for easier shipping...
    thanks!


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  12. mr_light

    mr_light AK Subscriber Subscriber

    Messages:
    322
    Location:
    Silver Spring, MD
    I think only the CR-XX20 series had the decoupler switch. I wish this one had it.
     
  13. mr_light

    mr_light AK Subscriber Subscriber

    Messages:
    322
    Location:
    Silver Spring, MD
    I can hook up the PRE-Out jacks to another power amp and see if there is a pop if that would serve the same purpose.

     
  14. asdf_x2

    asdf_x2 Active Member

    Messages:
    166
    Location:
    Finland
    Also CR-800 has it.
     
  15. mr_light

    mr_light AK Subscriber Subscriber

    Messages:
    322
    Location:
    Silver Spring, MD
    I hooked up a separate amp to the Pre-Out jacks and I get the Pop through the external amp. Sounds like it isn't in the power amp section...

     
  16. avionic

    avionic " Black Knights " Subscriber

    Messages:
    41,590
    Location:
    Fort Dodge, Iowa
    Does the loudness and filter switches enhance the "pop"..
     

     

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  17. Dr. Ear

    Dr. Ear Well-Known Member

    Messages:
    720
    Location:
    Austria
    A defective spark killer cap (the one soldered to the power switch) could also cause this.
     
  18. mr_light

    mr_light AK Subscriber Subscriber

    Messages:
    322
    Location:
    Silver Spring, MD
    I would like to try a replacement spark killer Cap-Resistor. The schematic shows the specs as .033 Capacitor, 120 Ohm Resistor 125vac. Any idea for a source?
    Would this work? "C5: OKAYA 0.2uF 120 Ohm 250V CAPACITORS-SPARK QUENCHERS"
     
    Last edited: Jan 20, 2013
  19. avionic

    avionic " Black Knights " Subscriber

    Messages:
    41,590
    Location:
    Fort Dodge, Iowa
    Last edited: Jan 20, 2013
  20. avionic

    avionic " Black Knights " Subscriber

    Messages:
    41,590
    Location:
    Fort Dodge, Iowa
    Should do fine..
     

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