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PC2002M Meter Board

Discussion in 'Yamaha' started by miklemke, Mar 4, 2018.

  1. miklemke

    miklemke AK Subscriber Subscriber

    Messages:
    859
    I recently repaired a PC2002M. Everything is great except the meters don't work. The problem is the IC on the meter board. I need a Yamaha IG00137 integrated circuit for a PC 2002M. It is for the meter driver. Same part also is used on a P2200. It goes on the meter driver board.

    I did post a WTB on Barter Town, but no replies. Does anyone have any leads on on of these, or is there a known work around?

    Thanks
     

     

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  2. clinic-audio

    clinic-audio all on YAMAHA untill 1990

    Messages:
    2,143
    Location:
    France
    Are you sure that all voltages are correct ? Because two channels affected together is strange ..
    IG00137 is specific to this model and I don't have anything on it ....
    IG00136 is used in CA2010 ( CA2000 in Japanese version of CA2010)
     
  3. miklemke

    miklemke AK Subscriber Subscriber

    Messages:
    859
    When i received the unit both of the 15V power supply fuses (F6 & F7) were blown. Fixed that problem and have +-15V now, but both of the meters peg to full when powered on. I have disconnected them to avoid damage to the meters themselves. Everything other than the IC check OK on the Meter Board. Not sure how to check that IC. Other than the meters, the amp itself works fine now.
     
  4. Mr. Yamaha

    Mr. Yamaha Not so much Yamaha lately...

    Messages:
    897
    Location:
    Amsterdam Area, The Netherlands
    Most likely the IG00137 can be opened up like the IG00136 of my CA-2000. There are 'normal' semiconductors and op-amps sitting in that box. Those op-amps tend to fail in most IG00136 problems.

    To take the case off is not really the problem, but to get to the PCB side, you need to remove the black kind of epoxy which is poured over the PCB.

    There are some people who managed to fix it. Please have a look here: http://audiokarma.org/forums/index....eter-driver-pm-02-ig00136-help-needed.790426/
     
  5. miklemke

    miklemke AK Subscriber Subscriber

    Messages:
    859
    Mr Yamaha==> thanks for the link. I'm going to open it up, can't hurt, it's already inoperative. I also ordered that generic meter driver, what's $9?
     
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  6. clinic-audio

    clinic-audio all on YAMAHA untill 1990

    Messages:
    2,143
    Location:
    France
    The meter box (IG00137) made by YAMAHA need to be refixed and can't be replaced by a kit (or other ) at 9$
     

     

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  7. miklemke

    miklemke AK Subscriber Subscriber

    Messages:
    859
    IMG_3037.jpg IMG_3038.jpg I removed the IC. The cover just popped off with an exacto knife. Will check the components and replace as needed. Will start with the opamps that seem to be the typical problem. The bottom is covered with epoxy, so rather than trying to removed it, I will just work from the topside. Will update when I'm done. Will have to wait for parts.
     
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  8. miklemke

    miklemke AK Subscriber Subscriber

    Messages:
    859
    The new opamps arrived. Because of the proximity of other components, I ended up removing some of the epoxy so I could work from the bottom of the board. I used an old soldering iron set at about 225 degrees. Hot enough to glassify the epoxy without much smoke, but not hot enough to melt solder. It took some time, but did the job. Picture attached. Unfortunately, replacing the opamps did not solve the problem. I guess I'll have to remove all of the epoxy and test the other components to find the problem.

    I did successfully replace the entire meter driver board with one mentioned in the thread Mr. Yamaha referred me to in his post above. I view that as a temporary fix with the ultimate goal being the repair of the IC on the meter board. Attached is a picture of that board. It does work. I will be cleaning up the wiring before buttoning up the unit. IMG_3066.jpg IMG_3065.jpg
     
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  9. miklemke

    miklemke AK Subscriber Subscriber

    Messages:
    859
    Here the meter drive is with the wires cleaned up: IMG_3067.jpg

    Here's the amp in full working order. I did use blue leds. Normally I'd use bright white, but wanted to see what blue would look like. IMG_3069.jpg
     
  10. miklemke

    miklemke AK Subscriber Subscriber

    Messages:
    859
    IMG_3735.jpg I kept working on the original meter board and found these two resistors? were open circuit on the meter board. On the schematic, they are shown as 10 ohm resistors. I replaced them with 10 ohm resistors and both meters now work with the original meter driver board. What are these??? they look like caps to me. I want to replace them with the correct items. If they are in fact resistors are metal film resistors OK to use as replacements?

    Thanks for your help.
     
  11. amr2

    amr2 Well-Known Member

    Messages:
    520
    They are 10pF 5% capacitors.
     

     

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  12. avionic

    avionic " Black Knights " Subscriber

    Messages:
    42,958
    Location:
    Fort Dodge, Iowa
    Nope. They are metal film resistors.
     
  13. avionic

    avionic " Black Knights " Subscriber

    Messages:
    42,958
    Location:
    Fort Dodge, Iowa
    Nope. They are metal film resistors

    The C-2a is packed full of these type of resistors but they are brown in color. Photo courtesy of milo63

    [​IMG]
     
  14. miklemke

    miklemke AK Subscriber Subscriber

    Messages:
    859
    AMR2 I also thought they were caps, that's why I was confused by the schematic and why I checked here.

    I dropped some 10 ohm resistors in and the meters are now working fine.

    Thanks Avionic!!
     
  15. amr2

    amr2 Well-Known Member

    Messages:
    520
    Ups, sorry. My mistake.
     

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