BA-5000 Rework

Discussion in 'Exclusively Sansui' started by HDJR808, May 10, 2016.

  1. kevzep

    kevzep Its all about the Music Subscriber

    Nice work, but don't you hate that, no idea what on earth caused all the shenanigans?

    Fingers crossed everything holds....
     

     

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  2. JOMARK911

    JOMARK911 Super Member

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    2,523
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    Athens Greece
    I keep mine crossed.
     
  3. HDJR808

    HDJR808 Active Member

    Messages:
    249
    The amp has been idling for several hours now as I slowly dial in the bias. I've gotten it within a mv or 2 so far by taking very slight tweaks, put the cover back on, wait an hour, tweak again, etc.

    The temperature seems to be holding at around 110F so far, far better than the slow continual uptick from when it was previously up and running. Although I had hoped for it to idle a little cooler, this may just be what I'm going to get...

    Is anyone familiar with the "fc" category on the KSA992's? Google only results in the barrage of online component resellers, with no actual info on the device. I have no recollection of when I got the ones that I have, and am curious about what the official gain range was for the "fc" designation.
     
  4. HDJR808

    HDJR808 Active Member

    Messages:
    249
    After a year or so on this project, I think it has finally wound down...

    As last mentioned, I was working on getting the bias dialed in, and with that complete, and idle temperature remaining comfortable, the front plate and top cover went back on. Still a bit of an ugly duckling, but no longer a basket case, I brought it downstairs (literally one step at a time) and into the main system it went.

    Happy to report that it sounds great and so far appears to be performing effortlessly. And one of the pleasant results to come out of this is that there is no "thump" at power up. Just the sound of the soft start relay clicking in and a very faint "tick" through the speakers that I assume is the reed relay on the buffer board as the protection circuit goes green.

    I want to thank all who posted encouragement and assistance during the course of this project, and use this opportunity to encourage others to tackle projects that might seem daunting. With all of the valuable input from this forum, there is so much that can be learned. While there are aspects of this rebuild that I still have to scratch my head about, the frustrations were more than counterbalanced by the enlightenment provided.

    So, let's see, what can I work on next...
     
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  5. ghamilton

    ghamilton Super Member

    Messages:
    1,416
    Location:
    ASHEBORO NC
    :needpics: CONGRATULATIONS!!!
     
  6. HDJR808

    HDJR808 Active Member

    Messages:
    249
    Okay, well I do have a shot of it back in its natural habitat:

    IMG_1653.JPG

    The power switch knob is from who knows what- it was on the amp as I got it. The level settings are at full, I just oriented them on the shaft that way because I like to see the machined witness marks. And the meter lamps are leds that were in my already working BA, so the collection of original green incandescent lamps that I cobbled together from the basket case and the parts carcass are now in that unit.
     

     

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