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Restoring Pioneer SX-790

Discussion in 'Pioneer Audio' started by Knutsul, Jan 25, 2018.

  1. merlynski

    merlynski Curmudgeon Electronicist Subscriber

    Messages:
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    Location:
    High Plains, Eastern Colorado
    https://www.ebay.com/itm/STK-0050-M...62326?hash=item1c9b75a376:g:9E8AAOSwaZJZhmtX+
    This is an eBay (USA) link to the circuit boards and heatsink mounting kit for the hbrown/rcs16 STK0050 upgrade modules. There is a parts list with part numbers for multiple electronic parts suppliers in that listing. Works for SX-790 and SX-780. You will need some assembly and soldering skills to do this correctly. Good Luck! :cool:
     

     

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  2. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

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    Mouser works best for me when I select a category off the main menu and then narrow down the parameters one by one. Hard to explain it in text.
     
  3. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    Caps are fairly easy. As I use Nichicon almost exclusively, the manufacturer # is 647.
    For example in the Search box you can type in 220uf 50v 647 and you'll get all Nichicon's.

    Now if you know what series you want (UPW/UHE for power supply, UKL for Signal Path Type in FOR EXAMPLE
    47uf 50v UPW and you'll get all the variations of the UPW's there.
    Substitute UHE or UKL and get their variations.

    It's fairly simple once you get the hang of it.

    There is a Parts list for the 780/790 already made up. A couple of the parts might be obsolete due to the age of the parts list, but we can do work around's. Especially if you post the list from this thread. http://www.audiokarma.org/forums/index.php?threads/sx-780-recap-list.213265/ POST #5. IT's from 2009 but I used it on my 790 in 2011. Dod a Forum search for 780 restorations. You may find an updated list.
     
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  4. Knutsul

    Knutsul New Member

    Messages:
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    Location:
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    What exactly is the signal path ? For example c106 looks for me to be in the signal path but the recap list on the link you sent me suggest :647-UPW0J471MPD.
     
  5. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    Signal path is what the signal from a source (for example a CD PLAYER) travels to get to the speakers. It's separate from the POWER SUPPLY and the Tuner (although the tuner is a source and provides a signal to amplify.). As C-105-106 go to ground they can be upw I think. Let me see if I can find my list of parts.

    I did my 790 in early 2010. I may have my old list on my old computer. Give me a day or two to look it up and see if there is something there. I don't remember there being so many UPW's on the 780/790. This could be someone's independent list and not Mark the Fixer's.
     
  6. Knutsul

    Knutsul New Member

    Messages:
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    Location:
    Holland
    Oke thats what I thought and why I found that list not in line with what you said. I will be patient and whait for your list. And some of these caps have a 20% variation. Does it matter is you have to place for example 2 .47uf caps and one is like 40uf and the other 52uf ?
     
    Last edited: Feb 2, 2018

     

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  7. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    It can, depending on where it's in the circuit. Stick with the stock values as much as possible. Any of the very small electrolytic caps of 4uf or less can be replaced with film caps IF there is room for a film. Panasonic ECQ type and Cornell Dublier DME's are both good for this.
     
  8. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    HERE's the Latest and Greatest from Mark the Fixer. NOTE that it doesn't include caps of less than 1uf. You're on your own for these. Panasonic ECQ's (Film) or Cornell Dublier DME or DSF series(Film) work well for those. This is a CAPS LIST ONLY. Add your Diodes, Put in new Regulator transistors (I'll find the #'s for ya) and stuff.

    Board # Part # Value Voltage Type Replacement Value Voltage. Note all are MOUSER #'s.

    AWE-099 C34 1 50V 010p 50 cea 647-UPW1H010MDD 1 50V
    AWE-099 C41 1 50V 010p 50 cea 647-UPW1H010MDD 1 50V
    AWE-099 C27 2.2 50V 2r2p 50 cea 647-UPW1H2R2MDD 2.2 50V
    AWE-099 c61 3.3 50v 3r3p 50 cea 647-UPW1H3R3
    AWE-099 C28 4.7 35V 4r7p 35 cea 647-UPW1H4R7MDD 4.7 50V
    AWE-099 C60 4.7 35V 4r7p 35 cea 647-UPW1H4R7MDD 4.7 50V
    AWE-099 C71 10 16V 100p 16 cea 647-UPW1C100MDD 10 16V
    AWE-099 c72 10 16V 100p 16 cea 647-UPW1C100MDD 10 16V
    AWE-099 c76 10 16V 100p 16 cea 647-UPW1C100MDD 10 16V
    AWE-099 C35 22 16V 220p 16 cea 647-UPW1C220MDD 22 16V
    AWE-099 C67 22 16V 220p 16 cea 647-UPW1C220MDD 22 16V
    AWE-099 C44 220 16V 221p 16 cea 647-UPW1C221MPD 220 16V
    AWE-099 C53 220 16V 221p 16 cea 647-UPW1C221MPD 220 16V
    AWE-099 c43 330 16v 331p 16 cea 647-UPW1C331
    AWE-099 C38 1 50V 010p 50 ceanl 647-UKL1H010 1 50V
    AWE-099 C40 1 50V 010p 50 ceanl 647-UKL1H010 1 50V
    AWE-099 c37 6.8 6v 6r8m 6 csza 647-UKL0J6R8






    GWK-118 C401 0.47 50V r47p 50 cea DSF? 0.47 50V
    GWK-118 C402 0.47 50V r47p 50 cea DSF? 0.47 50V
    GWK-118 C403 0.47 50V r47p 50 cea DSF? 0.47 50V
    GWK-118 C404 0.47 50V r47p 50 cea DSF? 0.47 50V
    GWK-118 c309 2.2 50v 2r2p 50 cea 647-UPW1H2R2 2.2 50v
    GWK-118 c310 2.2 50v 2r2p 50 cea 647-UPW1H2R2 2.2 50v
    GWK-118 C318 10 16V 100p 16 cea 647-UPW1C100MDD 10 16V
    GWK-118 C405 10 16V 100p 16 cea 647-UPW1C100MDD 10 16V
    GWK-118 C317 33 16V 330p 16 cea 647-UPW1C330MDD 33 16V
    GWK-118 C305 47 35V 470p 35 cea 647-UPW1V470 47 35V
    GWK-118 C306 47 35V 470p 35 cea 647-UPW1V470 47 35V
    GWK-118 C316 47 50V 470p 50 cea 647-UPW1H470MED 47 50V
    GWK-118 C319 47 16V 470p 16 cea 647-UPW1C470MDD 47 16V
    GWK-118 C301 100 25V 101p 25 cea 647-UPW1E101MED 100 25V
    GWK-118 C302 100 25V 101p 25 cea 647-UPW1E101MED 100 25V
    GWK-118 C303 100 25V 101p 25 cea 647-UPW1E101MED 100 25V
    GWK-118 C304 100 25V 101p 25 cea 647-UPW1E101MED 100 25V
    GWK-118 C307 100 50V 101p 50 cea 647-UPW1H101MPD 100 50V
    GWK-118 C308 100 50V 101p 50 cea 647-UPW1H101MPD 100 50V
    GWK-118 C311 220 16V 101_ 16 cea 647-UPW1C221MPD 220 16V
    GWK-118 C315 220 63V 221p 63 cea 647-UPW1J221MPD6 220 63V
    GWK-118 c406 220 6.3V 221p 6 cea 647-UPW0J221MED 220 6.3V
    GWK-118 C314 470 63V 471p 63 cea 647-UPW1J471MHD6 470 63V
    GWK-118 C227 0.22 50V r22m 50 ceanl DSF? 0.22 50V
    GWK-118 C228 0.22 50V r22m 50 ceanl DSF? 0.22 50V
    GWK-118 c207 1 50v 010p 50 ceanl DSF? 1 50V
    GWK-118 c208 1 50v 010p 50 ceanl DSF? 1 50V
    GWK-118 C103 2.2 50V 2r2p 50 ceanl 647-UKL1H2R2 2.2 50V
    GWK-118 C104 2.2 50V 2r2p 50 ceanl 647-UKL1H2R2 2.2 50V
    GWK-118 C117 2.2 50V 2r2p 50 ceanl 647-UKL1H2R2 2.2 50V
    GWK-118 C118 2.2 50V 2r2p 50 ceanl 647-UKL1H2R2 2.2 50V
    GWK-118 C229 2.2 50V 2r2p 50 ceanl 647-UKL1H2R2 2.2 50V
    GWK-118 C230 2.2 50V 2r2p 50 ceanl 647-UKL1H2R2 2.2 50V
    GWK-118 C201 4.7 50V 4r7p 35 ceanl 647-UKL1H4R7 4.7 50V
    GWK-118 C202 4.7 50V 4r7p 35 ceanl 647-UKL1H4R7 4.7 50V
    GWK-118 C217 4.7 25V 4r7p 25 ceanl 647-UKL1E4R7 4.7 25V
    GWK-118 C218 4.7 25V 4r7p 25 ceanl 647-UKL1E4R7 4.7 25V
    GWK-118 C324 4.7 50V 4r7p 35 ceanl 647-UKL1H4R7 4.7 50V
    GWK-118 C325 4.7 50V 4r7p 35 ceanl 647-UKL1H4R7 4.7 50V
    GWK-118 C326 4.7 50V 4r7p 35 ceanl 647-UKL1H4R7 4.7 50V
    GWK-118 C327 4.7 50V 4r7p 35 ceanl 647-UKL1H4R7 4.7 50V
    GWK-118 C213 47 6.3V 470p 6 ceanl 647-UKL0J470 470 6.3V
    GWK-118 C214 47 6.3V 470p 6 ceanl 647-UKL0J470 470 6.3V
    GWK-118 C105 470 6.8v 471p 6 ceanl 647-UKL0J471 470 6.8v
    GWK-118 C106 470 6.8v 471p 6 ceanl 647-UKL0J471 470 6.8v
     
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  9. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    Transistor list
    Q7/Q8 2sa726. Repl with KSA992. Replace when found pre-emptively.

    q11 2sc1775 ................................................ 512-KSC1845FTA
    q12 2sc1775................................................. 512-KSC1845FTA
    q13 2sc1885................................................. 512-KSC2383YTA
    q14 2sc1885................................................. 512-KSC2383YTA
    q15 2sa912................................................... 512-KSA1013YBU
    q16 2sa912................................................... 512-KSA1013YB

    Regulators
    Q19 2sd325R............................................... 512-KSC2073TU or 863-MJE15032G (*)
    Q20 2sb536L................................................ 512-KSA940TU or 863-MJE15033G (*)
    Q25 2SD712..................................................512-KSC2073TU or 863-MJE15032G (*)
    (*)MJE's are complete overkill to Handle Heat better. Need bigger Heatsinks tho as they are TO220 vs. TO-126.

    ISOLATION KIT for Heatsink
    532-4880MG with mica insulator, screw, washer, lock washer, insulating shoulder washer & nut. You need 3.
    534-4672 to-220 mica insulators $0.12 each
    get a few extra mica's, it's cheap insurance.


    q26 2sc1384.......................................................512-KSC2690A

    Get a couple or more of each type transistor for spares in case you need them.

    You'll need a tube of Thermal Grease. DO NOT USE ARCTIC SILVER!!!
     
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  10. Knutsul

    Knutsul New Member

    Messages:
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    Location:
    Holland
    Thank you so much !
     
  11. emresorkun

    emresorkun New Member

    Messages:
    10
    Hello Larry,

    I am also restoring a sx-790. Following your advise I decided to solder new diodes. I took a good look at the photos of your sx-790 and realized that the diodes you soldered are not touching the circuit board. Is there a particular reason to solder them like that? I mean the bigger diodes in the rare row.

    If you would advise to solder diodes like you soldered, please advise me a technique to do that. I spent 2 hours last night to find a way, I could not.

    Thank you for all your nice, informative posts,

    Emre
     

     

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  12. Watthour

    Watthour Electron Rancher - JS3600

    Components which could be subjected to passing relatively large currents can be stood off the circuit board to allow cooling air to flow around them more easily. A temporary spacer or clips can be used while soldering, or sleeves for the legs can be installed.
     
  13. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

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    I clip an alligator clip around the body so the clip is against the board. Solder the legs, let cool and un clip the Alligator.
     
  14. emresorkun

    emresorkun New Member

    Messages:
    10
    Thank you Watthour for explanation!

    Hello Larry! Thank you very much for the explanation ! I am heading to my electric shop to buy alligator clips!
     

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