Another Pioneer SX 1250 restoration

Discussion in 'Pioneer Audio' started by boris_CH, Jul 17, 2017.

  1. calman46

    calman46 AK Subscriber Subscriber

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    I always give the big can caps a visual check for leakage and find the most recent stabilizer board rebuild . Its the 1250's Achilles heal .
     
    jobrewer1983 likes this.
  2. boris_CH

    boris_CH New Member

    Messages:
    38
    Location:
    Switzerland
    Hey guys, some of the caps on the stabilizer board are glued and sticking to the board like crazy. How do you get rid of it? I don't want to use too much force, to not damage the board. Some heat from a hairdryer maybe?
     
  3. w1jim

    w1jim I can fix it but good... Subscriber

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    Grab them with a pliers - twist left and right to break the glue free - desolder and pull them off.
     
  4. boris_CH

    boris_CH New Member

    Messages:
    38
    Location:
    Switzerland
    Just desoldered all the caps from the stabilizer board and tested them. All but one were good. The little sucker C6 was dead... Waiting for my Digi-Key delivery...
     
  5. jobrewer1983

    jobrewer1983 AK Subscriber Subscriber

    Messages:
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    Location:
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    Great amp to do a full build on! :)

    If you check other posts you can see what is recommended. Such a fun build, the 1250 has a lot of good room to work with.

    Congrats! Looking forward to seeing the build!

    Kind Regards,
    John
     
  6. jobrewer1983

    jobrewer1983 AK Subscriber Subscriber

    Messages:
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    Please tell us you are not serious about pulling components off with pliers?

    Im no pro, but that is a very bad idea. you can damage the PCB.

    Im probably misunderstanding something... Nonetheless, for glued down caps, a hot blade works wonders.

    Use a Desolder gun, solder sucker, or solder wick. If you do need to use pliers, id be super carful.

    Kind Regards,
    John
     
    Last edited: Jul 26, 2017
  7. jobrewer1983

    jobrewer1983 AK Subscriber Subscriber

    Messages:
    1,762
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    Where is MTF and Zeb 1 on this one!!!
     
  8. jobrewer1983

    jobrewer1983 AK Subscriber Subscriber

    Messages:
    1,762
    Location:
    San Jose, CA
    Take a butter knife or a putty knife, heat it up. The blade will melt the adhesive.

    that adhesive is common in old JBL gear as well...
     
  9. tsd71

    tsd71 Gittin Some Head!

    Messages:
    2,635
    Location:
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    As I said before the first place to check is the stabilizer... caps, transistors, and diodes..
     
  10. KingBubba

    KingBubba "Too Much Stuff" Subscriber

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    The pliers and the left right are only to crack the glues contact, not to pull the cap off the board. It is done first; so you don't have to desolder and unglue at the same time.
     
  11. w1jim

    w1jim I can fix it but good... Subscriber

    Messages:
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    Location:
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    Correct - jeepers, you don't just rip them off!
     
  12. boris_CH

    boris_CH New Member

    Messages:
    38
    Location:
    Switzerland
    Ok, protection board has new caps and a new relay. Regarding the transistors I am a bit unsure. I ordered parts according the confirmed replacement list. It's saying
    2SC1166 (2SC1384) to be replaced with 512-KSC2690AYS. What Digi-Key delivered (left) looks a bit different from the original (right)... Is that the right one? (sorry, blurry picture...)
    IMG_0453.JPG
     
  13. boris_CH

    boris_CH New Member

    Messages:
    38
    Location:
    Switzerland
    Aaaand new caps on the stabilizer board...
    IMG_0463.JPG
     
  14. tsd71

    tsd71 Gittin Some Head!

    Messages:
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    Location:
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    There are a lot of unoriginal parts on that board mostly transistors,also a very big 2-3 watt resistor in the middle of the board that I never saw on that board before. Please follow the parts list and replace all the parts on that board, not just capacitors. It's a very easy board to work on. I've already attached a parts list for this board, somebody was in there before and I kinda don't trust their replacements. Also dont forget the trimmer resistors. The KSC2690 is a suitable replacement dont be alarmed by its size.
     
    Last edited: Jul 27, 2017
    boris_CH likes this.
  15. zebulon1

    zebulon1 Into Phase Linear's lately Subscriber

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    That board is a mess.
    Cobbled parts from other sets?
     
  16. boris_CH

    boris_CH New Member

    Messages:
    38
    Location:
    Switzerland
    Thanks for the advice. Just checked a couple of pictures in the net and yes, you're absolutely right. That board has some strange parts on it. Guess it will take a little bit longer than initially thought...
    For the 4 big filter caps I took a bit of risk and ordered some no name caps from ebay - coming from hongkong... hopefully they will be ok...
     
  17. boris_CH

    boris_CH New Member

    Messages:
    38
    Location:
    Switzerland
    Ok, got rid of all the transistors on the stabilizer board. The soldering points on the back were questionable, don't know who did what on that board...
    fullsizeoutput_456.jpeg
    And here is the patient - still a lot to do...
    IMG_0471.JPG
     
  18. tsd71

    tsd71 Gittin Some Head!

    Messages:
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    Location:
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    Yes you took a risk getting big caps from China. Mouser and Digikey have nice perfect fits caps that run about $22 each.

    http://www.mouser.com/ProductDetail/United-Chemi-Con/E32D800HPC223MD79M/?qs=sGAEpiMZZMukHu%2bjC5l7YRVHbWh2qrfWdXeaBhiu1VY=
     
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  19. Hipocrates

    Hipocrates AK Subscriber Subscriber

    Messages:
    967
    Location:
    Costa Rica
    hopefully they won't be like this. :no:
    RUICHI CD60.jpg

    Best case scenario you will get crappy weird branded caps with bad specs that can harm your hard work, I've removed hundreds of that garbage on several "serviced" units.
    Is always better get quality parts from reputable brands (Panasonic, Nichicon, Nippon-Chemicon, etc) and from reputable sources (Mouser, Digikey, etc) specially for this monsters:thumbsup:
     
  20. tsd71

    tsd71 Gittin Some Head!

    Messages:
    2,635
    Location:
    New Jersey
    Any news?
     

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