Pioneer SX 636 "muddiness" moved from right to left speaker???

Discussion in 'Pioneer Audio' started by pdxtim, Jun 15, 2017.

  1. pdxtim

    pdxtim Member

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    A flea market SX 636 initially had lower volume and clarity from right channel which persisted despite 4-5 DeOxit treatments to pots and switches. I was playing it tonight, and after switching speakers to be sure that the right side was still deficient, I noticed that now the left speaker sound is not up to par, the right side sounds great. I had also worked the knobs a few times while experimenting with different speakers. Anyone have any idea what could be going on? Thanks in advance for any help.
     
  2. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

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    power amps can have 2sa726 and DO have 2sc1451 transistors in them, control amps have 2sa726.
    These sound bad before they crap out completely and damage things.
    And they ARE intermittent in their misbehavior before the final zappp.

    Quite frankly they also have the problematic sky blue sanyo "capsistors" - capacitors short out gradually - guaranteed.

    once these caps and transistors (and a few others to bring it ALL up to the same level) are resolved,
    they are like the energizer bunny, they just keep going and going...
    and singing quite sweetly. You will be impressed, should you do this (with our help of course)
     
  3. pdxtim

    pdxtim Member

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    Thanks Mark. So where should I start with the "renovation"?
     
  4. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

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  5. pdxtim

    pdxtim Member

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    Thanks again Mark!
     
  6. pdxtim

    pdxtim Member

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    pioneer sx 636 1.jpg So Mark, I finally got the stripped screw out and was able to clean the faceplate of my SX 636 and it's lookin good. Also I think the multiple "DeOxits" helped, it sounds much better than a few months ago. In reading several AK posts though it seems the general consensus is that certain transistors and capacitors should be replaced or else one day it goes up in smoke. I'm not much of an electrician but could likely solder some new components into this thing. My question is: to prevent this thing from self-destructing, at minimum what should be replaced? I don't want to do an entire refurb, just replace the least number of parts to keep this thing from frying. Thanks!!!
     
  7. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

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    The transistor numbers and caps I explicitly called out.

    The thing is that once the work is done to access the board, it doesn't make a lot of sense to just do a few cheap parts - when a few more cheap parts will complete the task.

    Neglecting some obsolete caps, that list in the thread should still be under 20 bucks w/o shipping.
     
    Last edited: Aug 5, 2017
  8. pdxtim

    pdxtim Member

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    So Mark, I assume the list to which you're referring is the list you sent to BmWr75 regarding the "rushing sound" on his SX 636 on May 2, 2013. It looks like there's 150 or so transistors, caps, and other components that would need to be replaced, correct?
     

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