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Long term P2200 restoration

Discussion in 'Yamaha' started by dondoucette, Oct 2, 2018.

  1. dondoucette

    dondoucette AK Subscriber Subscriber

    Messages:
    504
    Location:
    Regina, Saskatchewan Canada
    I've been working on this P2200 for some time now, it originally was in horrible shape as it had been gigged for years by the keyboard player I bought it from.

    I'm in the home stretch and have no interest in taking any shortcuts now.

    The heatsinks on one side of this amp were smashed up pretty badly, I obtained a used set to replace. I have transistors out and cleaned them up, I have new compound and insulators and thought just for the heck of it I would test gain. I fired up my Sencore TF46 super cricket and the following is what I got.
    image.jpeg

    In the left column are the A909's and the right C1586's. Don't know what the gain was when the transistors were new but the spread now seems considerable.

    My question; did Yamaha bother to do any gain matching or no. I have 12 of each spare transistors, should I bother to install some that are more closely matched or not bother.

    Thanks for your time.
    Don
     

     

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  2. dondoucette

    dondoucette AK Subscriber Subscriber

    Messages:
    504
    Location:
    Regina, Saskatchewan Canada
    085F7C80-BE8B-4765-AB84-DB7ECCECA33F.jpeg

    This is the set I’m going to use. Best match I could come up with.
     
  3. dondoucette

    dondoucette AK Subscriber Subscriber

    Messages:
    504
    Location:
    Regina, Saskatchewan Canada
    All electrolytics replaced, chassis and faceplate straightened, damaged heatsink on right channel replaced with a decent used spare, pots cleaned, bulbs replaced.

    59A7AF07-AC3C-4421-865B-039B97EE96A1.jpeg
    2sa682 temperature detecting transistor, original on this channel was split open, replaced with a good used OEM.

    934021FB-35DC-4372-8E2B-5F55200273A1.jpeg 1E4A32AB-C5B3-43E3-A006-344803ACDB3F.jpeg
    Progress... its only been waiting 2 years.

    A9982DDC-22F1-45FA-9A59-0BB349716BFA.jpeg
    Done. (Sandblasted handles)

    C7B77650-5AA6-4171-9FD2-DA6BC73C0938.jpeg
    Now this one. Part of the chassis is broken and bent from being dropped, cord has been cut off.

    Ill have a look for burned up parts, test the output transistors, check electrolytics for shorts/open, replace the cord and bring it up on the variac watching current draw and looking for dc at the outputs. If all goes well a partial resto is in order, nothing too crazy, just make it look ok and work reliably.
    I’m rather enamoured with these old Yamaha’s, I’ve had 2 in my main system for a number of years now and i just can’t find fault with them.
     
  4. amr2

    amr2 Well-Known Member

    Messages:
    548
    Hello

    I am also restoring two P2200, thread here.
    The 2SA682 transistor attached to the heatsink is the bias transistor, not a temperature detector. Mine has the plastic slightly cracked, I replaced them with BD140, it has pretty close specs.
     
  5. dondoucette

    dondoucette AK Subscriber Subscriber

    Messages:
    504
    Location:
    Regina, Saskatchewan Canada
    EBD492F3-A95E-496B-B1C1-7D0BB216D177.jpeg
    It was rather tongue in cheek based on the service manual. LOL!
     
  6. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,668
    Location:
    Fort Dodge, Iowa
    Both right.. The transistor thermally tracks the outputs temperature and auto-adjusts bias as needed to prevent thermal runaway.
     

     

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  7. amr2

    amr2 Well-Known Member

    Messages:
    548
    Exactly! :thumbsup:
     
  8. dondoucette

    dondoucette AK Subscriber Subscriber

    Messages:
    504
    Location:
    Regina, Saskatchewan Canada
    Got the bent and broken chassis piece replaced
    0AA8BEBE-E272-4B9C-B1C4-09D8BAAE77EA.jpeg 02F6F37A-E582-433E-89FF-C515A3C47881.jpeg 36E108DE-CA97-43D0-9BA8-EE60005697A5.jpeg

    The faceplate is also bent so I will attempt to straighten it but if I’m unsuccessful I have a spare that I’ve sandblasted that I need to paint. A friend on mine has been working on duplicating the color Yamaha uses for the logo so we can screen print on the faceplate.
    C75861F6-11F6-42B9-9BFA-1A416960283A.jpeg

    I have new electrolytics on hand to replace what’s in this amp. I was a little dismayed to see that digikey no longer stocks my favorite Panasonic caps, but I’ve found some nice nichicon alternates to keep on hand. I’ve also ordered up my favorite EPCOS power supply caps, i like to order these only as needed.

    Amplifier modules look great, little dusty, but no heat damaged parts or heat damaged parts of the boards, in fact the caps look new, I wonder if this amp got damaged early in its life and was set aside with little use?

    Looking forward to firing this one up, of course my amplifier addiction has me owning more amplifiers than I have use for, and these Yamaha amplifiers are a particular favorite of mine.
     
  9. amr2

    amr2 Well-Known Member

    Messages:
    548
    Epcos B41456B9229M or UCC E36D101LPN223TDB7M are good choices for power supply caps.
     
  10. dondoucette

    dondoucette AK Subscriber Subscriber

    Messages:
    504
    Location:
    Regina, Saskatchewan Canada
    C55C5E2D-AEBC-46AC-A7CB-B7DB234B08FA.jpeg
    I’ve been using these since 2015
     
  11. amr2

    amr2 Well-Known Member

    Messages:
    548
    I have used both. UCC is cheaper than Epcos.
     

     

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  12. dondoucette

    dondoucette AK Subscriber Subscriber

    Messages:
    504
    Location:
    Regina, Saskatchewan Canada
    Yeah. The EPCOS is +/-20%, the UCC is -10%, +50%
    No listed impedance on the UCC and lifetime is listed 2000hrs@85C
    EPCOS seems an all round better cap, I don’t mind paying the extra for my amplifiers, if I repaired one for someone else it would be good to have a cheaper alternative.
     
  13. bmanone

    bmanone Active Member

    Messages:
    144
    Location:
    Calico Rock, Arkansas
    Ripple current on the EPCOS is 45A the ripple current on the UCC is 14.15A with a 7.8mOhm ESR. How much ripple current does the P2200 see in everyday use?
     
  14. Guest125

    Guest125 Active Member

    Messages:
    353
    It's ripple won't exceed the rating of the bridge.
     
  15. bmanone

    bmanone Active Member

    Messages:
    144
    Location:
    Calico Rock, Arkansas
    The P2200 parts list specifies a KBH-2504, I believe this is a 25A 400V bridge rectifier. @DeltaB based on your statement, the UCCs ripple could be exceeded causing them to overheat and wear out prematurely. Thanks for the response!
     
  16. Guest125

    Guest125 Active Member

    Messages:
    353
    The P2200's rated maximum current is 11.5A, so I don't think that they would be overheating. It primary fuse is only 7A. Consult the Service Manual for specs.
     
    Last edited: Oct 14, 2018

     

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  17. amr2

    amr2 Well-Known Member

    Messages:
    548
    11,5A@120V is the primary current at rated operation. It has two primary fuses, 2x7A
     
  18. Guest125

    Guest125 Active Member

    Messages:
    353
    Yes, it is. And rails are 80. And you have one on each side of the rails. I seriously doubt that in the P2200 the UCC caps are overheating due to ripple current.
     
  19. amr2

    amr2 Well-Known Member

    Messages:
    548
    Yes. I think the UCC are suitable..
     
  20. dondoucette

    dondoucette AK Subscriber Subscriber

    Messages:
    504
    Location:
    Regina, Saskatchewan Canada
    Sure they are. I’m not disparaging the UCC caps, but for my personal use I prefer the EPCOS
     

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