Leestereo's Restoration/Upgrade Of A Sansui AU-717

Discussion in 'Exclusively Sansui' started by Leestereo, Feb 10, 2015.

  1. Leestereo

    Leestereo Super Member

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    Discrepancies between the Sansui schematics and the actual physical circuit are rather common. In most cases it is due to changes during the production run. I think that you are referring the R32 and not R34. The 0.33µF film capacitor across R32 is stock (I did not add this capacitor). As for R32, but I cannot confirm that it is 180ohm or 270ohm (since I don't have any pictures that show this clearly and the unit is back with its owner).
     
  2. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    There appears to be a board layout difference between the driver board pictured in the SM and the pictures shown (for example) in Leestereo's restore thread.

    To deltalight
    Overall - don't sweat it, leave those resistors alone - it worked when it came from the factory like that.
     
  3. deltalight

    deltalight AK Subscriber Subscriber

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    The .33uF film caps look like they are used to "speed-up" and "catch" overload transients for TR09 to trigger the protection circuit. I've added them to both driver boards on the 717 I'm now restoring.
     
  4. amit

    amit New Member

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    Hello Lee,

    I read this thread a couple of days back and I am delighted to see the efforts and the passion with which you have rebuilt the Sansui AU 717.

    I also have the same amplifier and plan to rebuild it or rather recap it. Is there any way to help me out with a list of all the components that I can order and build it just like the way you did or maybe with the same values . One of my large filter caps have also started leaking and there is uncontrolled movement of the speaker as i turn up the volume and the bass is very loose and not tight even in aux input leave alone phono. Please suggest a site from where I can order as I live in India and it is very difficult as many online sites or companys do not ship here. I would never let go this amp as I have listened to so many but this is the best !

    Best Regards
    Amit
     
  5. Hipocrates

    Hipocrates Anti-Muppet Subscriber

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    Hello, Welcome to AK, you can buy the components here http://www.mouser.in/; regarding a list, I'd suggest that start a new thread, replace the component with what you got on your amp as reference, and use this thread as a guide on some specifics boards.
     
    Last edited: Feb 22, 2017
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  6. Leestereo

    Leestereo Super Member

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    +1 for Mouser, very responsive to customer needs.
     
  7. amit

    amit New Member

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    Thank you guys for the information, guess I will order through mouser.in
     
  8. jake

    jake New Member

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    Hi,

    Is it just OK to use the green mylar capacitor for C19, C20, C21and C22 in PCB 2663? Thanks.

    Jake
     
  9. Hyperion

    Hyperion Roobarb & Custard Subscriber

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  10. jake

    jake New Member

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    Thanks for your recommendation John..

    For C606 and C607 (still in 2663), can I use 22uF/50V electrolytics (as a replacement) instead of the original 4.7uF? I ran out of 4.7uF and I still have lots of 22uF available.
     
  11. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    You'd better not - as this will slow up the flashing red protector light considerably - so I think these are off limits for value upgrade ;) The good news is these are non critical - so you can use the plainest Jane 4.7µF, 50V capacitors you can find..
     
  12. jake

    jake New Member

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    Thanks John. Thanks to Lee too for this very nice thread.
     
  13. divu

    divu New Member

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    Thanks Lee for this detailed tutorial. Thanks to you, I have successfully recapping my Sansui AU-717..No problem until now...All works fine..You are a true professional..Thanks again!
    Divu
     
  14. Overundr1

    Overundr1 AK Subscriber Subscriber

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    Have one on the bench this week, first one to get the mods. So far both driver cards responded happily to the upgrades, will note the bias and offset dialed in perfectly and as stable over time as any 717 I have reworked. Will report back as I get through the rest of the amp. Really curious as to tonality changes once I get the tone board redone (which has a dropped signal path issue to track down first). Cool stuff this.
    Anyone ever mention how much of a time consuming pita it is to get off that glue without damaging the surface of the cards, both amp cards were badly contaminated but came out nice after a long stint of personal attention :)

    -Lee
     
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  15. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    The '517 I did recently was pretty bad, splashed all over the topside yellow wire jumpers - nasty, but it too cleaned up well, that's all it needs, determination and patience. (oh, and the right cleaning solvent ;))
     
    Last edited: Jul 16, 2017
  16. Overundr1

    Overundr1 AK Subscriber Subscriber

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    You forgot to mention continued curmudgeon muttering :)
     
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  17. deltalight

    deltalight AK Subscriber Subscriber

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    Per a previous thread on glue removal, I use toluene sparingly. I tear off a piece of paper towel of the same size as the glue area. Place it on top of the glue, and then drip some toluene on the paper. The glue is now softened after about 3-4 min at which point you can use a small probe to remove it completely with no board scratches. When finished, make sure to remove all traces of the toluene to outside and do not touch the stuff as it gets absorbed through the skin. Rubber gloves might be a good idea here.
     
  18. Overundr1

    Overundr1 AK Subscriber Subscriber

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    Acetone on cotton balls outside for me, don't want those fumes in the shop.
     
  19. Overundr1

    Overundr1 AK Subscriber Subscriber

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    Anyways, I really like what LeeStereo has done with the 717, all the suggested changes make sense notwithstanding the don't change the caps crowd cringing over wholesale component replacement. Will be interesting to listen critically to the differences once done between the 717 and my restored, recapped AU-9900 used as a pre-amp into the BA2000. I expect better low end resolution, better medium volume clarity and a dead quiet noise floor from the 717. Will add to the thread as I work through the rest of the boards (or start a new one to not mess up this already awsome thread.)
    -Lee
     
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  20. Robert.garb

    Robert.garb New Member

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    Really great thread. Just read through the entire thing as I am getting prepped to do my own component selection etc for a 717. Been looking for an AU-717 for a long time and finally got one!
     

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