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Frankenstein Pioneer SX 737

Discussion in 'Pioneer Audio' started by rossm, Oct 7, 2018.

  1. rossm

    rossm AK Subscriber Subscriber

    Messages:
    273
    Hi
    If the lows get any lower I think the wife will come downstairs and beat me!! I have it Hooked to a pair of NHT 2.9’s and it’s 35 wpc is really shaking the music room and it’s not a small room, I may revisit the transistors at a later date, really need to finish up the Kenwood KA-9100 that’s been on the bench way to long.
     
    Last edited: Nov 3, 2018
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  2. Eastham

    Eastham More Class-A than ever!

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    Not exactly lowers the bass but lessens the boom and enhances the kick. Best way I can describe it lol.
     
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  3. eiraved

    eiraved Plane Whisperer Subscriber

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    If I may add, more bass accuracy is what you'll get.
     
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  4. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    When that 1451 decides to go (and it's a matter of WHEN, not If) it may or may not give you warning (snap, crackles, and pops like Rice Krispies) Usually short lived. It WILL die! And if you haven't replaced it before hand, pretty much figure on replacing 80% to 90% of the components on the AMPLIFIER BOARD! Seen it happen 1st hand on a SX-1010. Ended up replacing EVERY brand new CAP, Transistor, and 3/4 of the resistors on the board.

    If the AMP board on the "B" unit is working, pull it, overhaul it, and keep it for a spare. DO IT NOW! Then when the "A" unit starts the Rice Krispie Shuffle, swap boards and rebuild the "A" board at your leisure.
     
  5. Watthour

    Watthour Electron Rancher - JS3600

    Are you in the U.S.? If you wanted to throw it in a UPS box...
     
  6. Eastham

    Eastham More Class-A than ever!

    Messages:
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    Location:
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    When the 2SC1451 in my 7500 started leaking voltage it leaked rail voltage to the outputs, my right speaker was subject to 38v for a second or so before the protection circuit was like "Hell no brother" and kicked the relay out. Thankfully my speaker was fine and is still happily bumping to this day. Crazy thing is that the 1451 never shorted, it just leaked voltage. Ended up with new transistors through out apart from the outputs and drivers, but I have replacements for those if I ever decide to replace them.
     

     

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  7. rossm

    rossm AK Subscriber Subscriber

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    Ok, you guys have convinced me, I promise to leave it off till I replace the transistors. Would hate to damage such a nice receiver. Thanks for keeping me on track
     
  8. eiraved

    eiraved Plane Whisperer Subscriber

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    You may as well replace those large cans while you're in there. You'll thank us later...;)
     
  9. rossm

    rossm AK Subscriber Subscriber

    Messages:
    273
    Was looking for new main caps today, I need 2 68000uf 50v checked mouser and they are out of stock, checked arrow and prices seem pretty high.
    anyone have a good source? No eBay or China caps.
    Would also go larger if need to
    Thanks
     
  10. redk9258

    redk9258 AK Subscriber Subscriber

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    Hope you mean 6800uF.
     
  11. eiraved

    eiraved Plane Whisperer Subscriber

    Messages:
    2,251
    Location:
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    You probably were searching for 68000uf caps (instead of 6800uf), which explains why Mouser had none available. Mouser has plenty of 6800uf 50v caps in stock, which is what the SX737 uses. I probably would go a bit larger in order to find caps that will fit properly on your unit.
    I prefer using Digikey to find caps (no affiliation). Their filtering engine seems to go into better detail in allowing the user to filter out capacitor selections which aren't needed, which is a big help when you're staring at hundreds of caps while trying to find the perfect one.
     

     

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  12. rossm

    rossm AK Subscriber Subscriber

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    Good thing I didn’t order them, might have been a tight fit. Thanks
     
  13. rossm

    rossm AK Subscriber Subscriber

    Messages:
    273
  14. rossm

    rossm AK Subscriber Subscriber

    Messages:
    273
    Thanks for the catch too many 0’s , no wonder they were so expensive , guess I was looking for some really low end..
     
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  15. UncleBingo

    UncleBingo AK Subscriber Subscriber

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    If you want to PM me your address, I'll send you the replacements for the 2sc1451's gratis. I have several sitting around. Pretty sure they're KSC3503.
     
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  16. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
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    Location:
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    Take the Mains up to 8200uf 63V. Gives you a little more voltage wiggle room (headroom), and the 737 can handle 10Kuf easily. Mine runs 8200uf/63v, and they fit inside the old cans'. Don't go higher than twice the value. And yes Uncle Bingo the replacement for the 2sc1451 is the KSC3503.

    These will do just fine. If you stuff the old can caps, just run wire out the bottoms and tie/solder to the existing leads. https://www.mouser.com/ProductDetail/Nichicon/LLS1J822MELB?qs=sGAEpiMZZMtZ1n0r9vR22TrbYqu733AyZZHjJNEqjSs= $5.15ea.
     
    Last edited: Nov 10, 2018
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  17. eiraved

    eiraved Plane Whisperer Subscriber

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    What is the diameter of the original cans? There are several adequate 8200uf 63v choices available @ 1.378" diameter, and some even larger. If that size will fit, it'll save some time from having to gut the old cans and then fit the smaller caps into the old cans.
    These cans are 1.417" in diameter and are 2.04" tall. It'll work if they fit inside the clamp and if they aren't too tall and interfere with the receiver cover installation. I do like caps with screw-on terminals!
     
    Last edited: Nov 10, 2018

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