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Yamaha CR-2020 popping

Discussion in 'Yamaha' started by whiskeydump, Jul 1, 2016.

  1. whiskeydump

    whiskeydump New Member

    Messages:
    23
    Location:
    Virginia
    Hi guys, I'm getting a loud popping through both speakers with this receiver. Some background info and what I have observed so far:

    - Bought off craigslist in the Northern Virginia area last year. Original owner said service bulletins had been performed at some point by an AKer in Maryland (merrylander?).

    - Worked fine for around two months, and then a loud popping started intermittently. Sometimes shortly after start up, sometimes after an hour of clean listening. Sound never cuts out or the receiver never turns off, just a loud "pop" or "pop-pop," sometimes every 30 minutes, sometimes a couple times in a 5-minute period. Popping volume seems volume dependent, as in how loud the pop is corresponds to how loud the music is. Doesn't matter what input source or speakers. Do sometimes hear the pops when no input is playing, but more often when there is one playing.

    - Took in to local hi-fi repair in Virginia and they could not replicate the problem. Took home and problem immediately presents itself. Put aside for 4 months. Do my first attempt at de-oxit (not super thorough, admittedly) recently when I got a turntable. Popping seemed to be gone after de-oxit and having sat for 4 months and then after 15-20 hours of combined listening, now it's back.

    - I was sitting next to it waiting to see if the meters jumped when it popped today and for the first time I actually saw a decent sized static/electric arc inside through the metal grill on top when it popped.

    Any ideas? Ideally I would have someone work on it but I was a little disheartened paying $50 to have it sit in a shop and not have the problem replicate and I don't know where else in the DC Metro area to try.

    I also had the thought that maybe it was the electricity in my home if the problem didn't replicate somewhere else, but I've never had an issue with any modern equipment. Now seeing the spark / arc I hope that's enough info to hopefully point me in a direction. I've said before that I hate to part with it because I do love the way it looks and sounds with a "new" set of Polk SDA-1C's I just got, but I'm almost ready to give it up in favor of reliability of something else.
     

     

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  2. HypnoToad

    HypnoToad Ms Puss Puss Subscriber

    Messages:
    6,046
    Location:
    Melbourne, Australia
    It pops in both channels? Had the same thing with my CR-1020, if I watched it the relay would click in and out quickly, it's most probably in the PSU PCB or capacitor PCB, I recapped mine and put in new voltage regulator transistors, then I was tapping stuff with the wrong end of a screwdriver and soon as I touched the fuse it stopped, pulled the fuse out and cleaned it problem solved. Not saying that is your problem though but something to check. Check the underside of the PCB's with a good magnifier for cold solder or cracked joints.

    Other more knowledgeable people will be along with ideas as well.
     
  3. whiskeydump

    whiskeydump New Member

    Messages:
    23
    Location:
    Virginia
    Thanks for your reply, it is both channels that pop. I'll get it apart and watch the relay this week. Just for clarification are you saying you think it was the fuse all along and not caps or transistors?
     
  4. HypnoToad

    HypnoToad Ms Puss Puss Subscriber

    Messages:
    6,046
    Location:
    Melbourne, Australia
    I replaced all the electrolytics on the PSU pcb and the regulator transistors, it still popped, I decided to check the fuse after tapping on it, once I did that it stopped popping, so I can't really say. But it's as solid as a rock now. The electrolytics were not in good shape most of the plastic sleeves had shrunk, and it runs much cooler with the new transistors, so I would change those out anyway.

    If you take the PSU pcb out, check the underneath for cold solder and/or cracked joints as well.
     
  5. whiskeydump

    whiskeydump New Member

    Messages:
    23
    Location:
    Virginia
    It does seem to run fairly hot. I'll post back if I get anywhere with the fuse. If anyone else has thoughts or suggestions I'm all ears, thanks!
     
  6. clearsoft

    clearsoft New Member

    Messages:
    9
    I had a similar issue with my CR-1020; intermittent popping from both channels and a bit of low level hum at initial turn on. Read every post here for Yamaha CR relay/no sound/clicking and viewed many youtube videos. Many many hours of troubleshooting, so wanted to share here in the hopes of saving others some heartburn.

    After a full power supply recap (both pcbs) and power transistor upgrade to higher voltage TIP31C in the supply, the protection relay would not fire. The -25V output sat at -10V. Cleaned the flux and grime off the bottom side the PCB and the output went to +6V. Disconnected the two purple wires from the -25V post to eliminate loading. No improvement. Removed and retested all 4 transistors; junctions not shorted nor open.

    Decided to look at the .01uF capacitors. In circuit across the terminals, the one on the -25V supply measured 6 kOhms whereas the one in the +25V supply measured 3 megohms. Pulled the caps; neither was leaky. Pulled the 4 transistors again. Still 6 KOhms...strange.

    Used flux remover to clean the top side of the PCB around the .01uF cap locations, removing glue residue around the heatsinks. Resistance now 2 megohms. Apparently the glue that Yamaha used was not electrically benign and the -25V supply is extra sensitive to leakage current (check out the circuit topology).

    Reinstalled all components. Reconnected all wires. Voltages perfect. Relay works.
    —Ed
     

     

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  7. savatage1973

    savatage1973 Addicted Member

    Messages:
    6,186
    Location:
    NW Pennsylvania snow belt
    The CR-2020 and its "big brother", the CR-3020 both run quite hot (I have both). This issue is addressed in the Service Bulletins. It will still run hot, but not desolder itself as they are know to do in stock configuration. If you look, and if the service bulletins have been addressed, you should see scorch marks on the board, and note that several resistors have been replaced and set much higher up and away from the board for better heat dissipation. Make sure that the power switch modification (from the service bulletin) has also been done--if not, the switch will eventually fail, and they are "unobtanium".

    Good Luck!!!
     
  8. sssboa

    sssboa Well-Known Member

    Messages:
    657
    Popping in both channels is most likely caused by an overheated dying transistor on power supply. Look for hot transistors with big radiotors. Replace them with equivalents. Add bigger radiotors or screw them to the case on some isolation pads.

    dyingtr.JPG
     
  9. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,685
    Location:
    Fort Dodge, Iowa
    This thread is over 2 years old.
     
  10. sssboa

    sssboa Well-Known Member

    Messages:
    657
    Not now
     
  11. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,685
    Location:
    Fort Dodge, Iowa
    True..
     
    Samokan likes this.

     

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