Accuphase E-202 with static/whistling

Discussion in 'Kenwood-Trio/Kensonic-Accuphase' started by Vaughn, Aug 1, 2017.

  1. Vaughn

    Vaughn AK Subscriber Subscriber

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    I just purchased this beauty here on BT and it looks like something might have gone amiss during shipment. There is no physical damage but when I turn the amp on there is some hum before the relay kicks in. When the relay does kick in there is a loud static/whistling sound when the selector is on Disc 1 (nothing connected) that is still audible, if reduced in level, when the selector is on other settings. This amp was rebuilt in 2012 by Echowars so I'm not sure what it could be. It seems like it might be a transistor that has gone noisy but I'd love your opinions on it before I haul it into the technician. I know there are boards in this amp that socket into connectors, is it possible one of these is slightly loose? In any case I've attached a video showing the problem
     
  2. Vaughn

    Vaughn AK Subscriber Subscriber

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  3. slimecity

    slimecity Super Member

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    Looks like a noisy transistor in one channel of your phono section.

    Probably best for Echowars to chime in before you do anything but....

    What I would do in your sitn is pull the phono board, pull the trannies from that board and test them all.
     
  4. Vaughn

    Vaughn AK Subscriber Subscriber

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    Thanks for the input, I dropped it off at the shop yesterday. This amp is too nice for me to go poking around in...I need to practice my solid state repair skills on one of my lesser amps. I figured it was a noisy transistor and I have faith the gentleman I have working on it will find and fix the problem. I'll check back in and let you all know what the verdict was!
     
  5. Vaughn

    Vaughn AK Subscriber Subscriber

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    Checked in with my tech and it seems to be noisy transistors on the phono board. Problem is, this transistors are no longer available and the subs that are supposed to work are not. He says the originals are high gain and closely matched. In any case, if I can't get this going I've lost close to $1k. Anyone out there an expert on these and could offer advice? Here is what he did;

    On Equalizer Amp Assy (page 5),
    For 2SA776, substituted KSA992
    For 2SC1416, substituted KSC1845

    Any help is greatly appreciated!
     
  6. inductor

    inductor Super Member

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    the tech should be able to repair it, if not find another one (tech)
     
  7. slimecity

    slimecity Super Member

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    No worries of that occurring. There will be replacements for the trannies in your phono section.

    It looks like your tech is onto it.

    The 992s and 1845s are extremely common transistors BTW. No "unobtanium" parts there.
     
  8. Vaughn

    Vaughn AK Subscriber Subscriber

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    He has already subbed the transistors with the 992s and 1845s and says they aren't working as they should. I guess I should retrieve the amp and try a different tech. He seemed like he knew what he was doing.
     
  9. slimecity

    slimecity Super Member

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    So I wonder if he did end up "matching" them as he stated.

    Getting the correct gain replacement is also important.

    I did a quick search and Ksa/2sa992 (grade F) is recommended as a sub for the 2SA776.

    Ditto the KSC1845 (F grade) comes up as a good sub for the 2SC1416.

    Accuphase circuits are fairly "fine tuned," and this circuit could well have a low tolerance for incorrect part matching. Its possible that even the recommended subs may cause issues.

    It would be good to get a description of what symptoms to the "not behaving" you are getting.

    I hope you get it fixed.
     
    Last edited: Oct 1, 2017
  10. Vaughn

    Vaughn AK Subscriber Subscriber

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    My tech decided to put the original transistors back in, which he had tested upon removal and all tested good. When he reinstalled them the problem vanished. He isn't completely sure why this happened and so gave me a good deal on the repair. My guess is something was jostled during shipment and wasn't making good contact. In any case the amp is up and running and sounds fantastic with my Kef Concertos:beerchug:

    IMG_0560.JPG
     
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  11. inductor

    inductor Super Member

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    dry joints eh
     
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  12. Vaughn

    Vaughn AK Subscriber Subscriber

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    Meh, problem has returned. What a pain in the ass. I have initiated a return through PP. I don't have all of the time and money in the world to have this thing in and out of the shop constantly. Thanks everyone for you input!
     
  13. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    Shame
    Looks like a nice piece. Probably something stupid that will take time to find. It happens:dunno:
     
  14. Vaughn

    Vaughn AK Subscriber Subscriber

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    It is a beautiful amp and I've wanted one for ages. Intermittent problems are the worst and even mentioning that to a tech seems to make the best of them apprehensive about undertaking a repair.
     

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