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Pioneer SX-1250 Keeps blowing speakers right channel, Ideas Help?

Discussion in 'Pioneer Audio' started by electrocuted, Oct 9, 2018.

  1. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    Are we talking about the same diodes? The horseshoe shaped ones that are screwed to heat sinks have white insulated wires running to them.
     

     

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  2. kevzep

    kevzep Its all about the Music

    Yes these are the STV3 Diodes as stated above, yes they have the white insulators on them but they are single strand wires and break off the diode very easy.....
     
  3. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    ok thanks for that tip. Sounds like I'm going to be working on a glass project with eggshell parts.
     
  4. rcs16

    rcs16 Super Member

    Messages:
    3,898
    Location:
    Baldwin, Ontario, Canada
    I always apply a little bit of glue (epoxy) to secure the fragile STV wires. push the sleeving back a bit to get glue on the leads where they enter the horseshoe pkg, then let the sleeving go back to it normal position so all gets glue & secured, done deal.
     
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  5. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    I like that tip!!! Sounds like a great idea, Thanks
     
  6. WE6C

    WE6C Well-Known Member

    Messages:
    516
    Location:
    Colfax, Northern California
    I tried something once and was pleased with how it turned out. I layed the diode out flat and used silicon rubber gasket maker and formed it about 1/2 to 3/4 inch from the "horseshoe" It is now completely encased in rubber for that !/2 inch or so. Now if the wire for some reason was to break, I can remove some of the silicon rubber and repair the wire.

    It's a good idea to check these diodes with your DVOM on diode test. Keep in mind I've discovered that the cheap/free/throw away DVOM's sometimes don't have enuff output to check these. Same as the "give away free" meters you see advertised. The reason is they are basically three diodes in series so it takes the better meters to read them.

    As Kev mentioned above, you can't be careful enuff.

    The reason I asked above if they were there is some people don't realize how critical they are and also what they are.

    Bob
     
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  7. WE6C

    WE6C Well-Known Member

    Messages:
    516
    Location:
    Colfax, Northern California
    I think I need to clarify one thing... the diode itself is not encased in the silicon rubber, only the wires up to it so the diode itself still can make solid contact with the heat sink.

    Bob
     
  8. z-adamson

    z-adamson AK Subscriber Subscriber

    Messages:
    1,542
    Pretty sure you are wrong here.

    Those leaded blue radial caps with black stripe are probably Nichicon KT series which are rated to 105c.
     
  9. kevzep

    kevzep Its all about the Music

    I know, I didn't see the KT caps in the first pictures. I use the KT for audio path myself in my own restorations.
    Odd choice of caps in my opinion as they have 85˚C caps in the power supply where they should be using Nichi PW series, but they use FG series...
    The selection of caps is not the route I would take and many others.
     
  10. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

    Messages:
    32,381
    Location:
    Central Missouri
    Just read the thread and it appears the OP's offset readings were 2 and 5 mV which I would have thought would be fantastic, did everyone agree that's not the problem and I just missed it?
     
  11. kevzep

    kevzep Its all about the Music

    I think there was some random "popping" from one channel IIRC.....the offset is not the issue, it could be 50mV and not be the problem...
     

     

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  12. z-adamson

    z-adamson AK Subscriber Subscriber

    Messages:
    1,542
    It could be 500mv and not be the problem.
     
  13. z-adamson

    z-adamson AK Subscriber Subscriber

    Messages:
    1,542
    Those readings are great.
     
  14. z-adamson

    z-adamson AK Subscriber Subscriber

    Messages:
    1,542
    Out of curiosity, what is wrong with UFG in the power supply?
     
  15. kevzep

    kevzep Its all about the Music

    They wont last as long. PW is a better design for power supply applications where there is a lot of ambient temperature.

    Use whatever, makes no difference to me, I am saying what I use when I am restoring Pioneers. Its a free world and if you think fine gold is the way to go, then knock yourself out.....
     

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