Pioneer Sa-9900 in the worst state i've ever seen an amp

Discussion in 'Pioneer Audio' started by reddish75, May 13, 2017.

  1. reddish75

    reddish75 Active Member

    Messages:
    177
    Hi,

    Having bought a Sa-9900 as faulty I thought it would be easy enough to repair as I've restored quite a few vintage amps just not any pioneers, anyway I've opened it up and WOW what a mess, someone's been in there and completely butchered it, some of the highlights of the many problems are all transformer wires have been cut and rejoined insulated with electrical insulation tape, one of the bass control shafts been replaced and then ridiculous amounts of solder used to secure this in place (pics to come on this one) and lots of components replaced with what I can only think was a blowtorch.

    So I'm going to need some help and pointers on this one!

    I'm starting with the power supply regulator card on which I will need almost new everything, I'll start with the transistors I need cross references for everything if someone could help me with that and also the best caps to use and possible some pointers of how best to sort the trace side of the board (you'll see what I mean in the pics below and yes that is blu-tac).

    [​IMG]
    [​IMG]
     

     

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  2. LesE

    LesE 110284 Subscriber

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    Sounds like you have quite a challenge ahead of you. The SA-9900 isn't the easiest to work on at the best of times.

    Here is the parts list I used when I reworked my SA-9900 last summer. Note that some of the items listed are optional.

    Good luck.

    Les.

    SA-9900 Component List
     
    Last edited: Jul 18, 2018 at 1:06 PM
  3. Ohighway

    Ohighway Wannabe Minimalist Subscriber

    Ouch...
     
  4. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    DAMN! That's almost as bad as the driver board on a Sansui 9900 I have that I gave up on. You should be able to retrace the path's fairly easy on this board.
     
  5. SaturationPt

    SaturationPt AK Subscriber Subscriber

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    Not loving that wire "fuse".
     
  6. slayer44

    slayer44 AK Subscriber Subscriber

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    Yuck!...I would start all over with a "new" board. Hack jobs turn into bigger hack jobs when trying to salvage stuff this bad...I am sure you were already planning on doing this. Good luck!
     

     

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  7. QSilver

    QSilver Super Member

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    An Alcohol bath for the board is probably gonna be a good start... so you can see how bad the damage on the PCB really is....
     
  8. c.coyle

    c.coyle AK Subscriber Subscriber

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    Caulk and off-brand capacitors. Never a good sign. All that solder can only means mangled traces. And it looks like a hurricane blew those small components over. Is it the camera angle, or is the board warped?
     
  9. Markoneswift

    Markoneswift Quartz locked n ready to rock

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    You can borrow this if you like - it's obviously the 'right tool for the job'....

    old-reliable.jpg
     
  10. Markoneswift

    Markoneswift Quartz locked n ready to rock

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    Can we get a match on the finger prints in the Blu-Tac ? If we can, we can send some boys round to 'have a word' with this person :whip:
     
  11. QSilver

    QSilver Super Member

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    You know, I actually have one of those irons.... but not for electronics.... :rflmao:
     
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  12. LesE

    LesE 110284 Subscriber

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    Those TO-126 transistors are replacements for the original TO-92L's. The AWX-073 Volume Assembly is situated immediately above the Power Supply assembly and the person who installed the TO-126's probably didn't realize that there would be a clearance issue. This could have been avoided by forming the leads to allow the device to be installed closer to the board. That's likely the reason why they are bent over.

    The aluminum heat sinks on the pass transistors are not original but are much needed because they run insanely hot. In my case, I moved the transistors to the large heat sink where the outputs are installed.

    Looking at the OP's Photobucket, I noticed the there are TO-126's on the power amp board so it appears that the C1451's and the A809's were replaced which is a very good thing. So it looks like whoever worked on this amp before had good intentions but the execution was rather poor.

    Les
     
  13. reddish75

    reddish75 Active Member

    Messages:
    177
    Well work has commenced, as you can see a lot of solder pads are no longer there so cue using component legs as new traces and soldering as little as possible
    to the tracks, the most difficult part I'm envisioning will be the TO-126 and associated transistors as there's virtually no traces left.

    [​IMG]

    [​IMG]
     
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  14. LesE

    LesE 110284 Subscriber

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    Looks like you're making good progress. Hang in there!

    Les.
     
  15. QSilver

    QSilver Super Member

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    An alternative if the traces are gone and you need to get a transistor to "hang on" to the board. Buy some small eyelets and push them through the hole to give the transistor a good anchor. I've had great results with this method. I got some small eyelets and drilled the PCB hole out a tiny amount with a 1.5 or 2mm drill and then squeezed the eyelet through - tight secure fit.
     
  16. zebulon1

    zebulon1 Getting behind on work. I need help? Subscriber

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  17. QSilver

    QSilver Super Member

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    That's them! You're welcome :thumbsup:
     
  18. Hipocrates

    Hipocrates Anti-Muppet Subscriber

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    And you can clean the board too, it will help to see better cracks and stuff, good work man:thumbsup:
     
  19. slimecity

    slimecity Super Member

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    Bon Jovi, what a state that PCB is in.....

    Look like he had his soldering iron heated to a scorching 5 degrees centigrade, judging by how that solder looks....
     
  20. avionic

    avionic " Black Knights " Subscriber

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    Acetone and a 2" paint brush will make the foil side look a helluva lot better.
     

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