AU-X11 reconditioning

Discussion in 'Exclusively Sansui' started by Hyperion, Mar 16, 2018.

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  1. SanthoshA

    SanthoshA Active Member

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    If possible can you post pictures or details and parts sourced for replacing the speaker relays and also the speaker terminals, i have a broken terminal in mine, would be grateful if you can add the details in your thread.
    By any chance are you also replacing the RCA lugs?

    I plan to do this in the last or once the other parts of the amplifier are done.

    Nice to hear that the X11 is in good shape !
     
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  2. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Last edited: May 8, 2018
  3. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Well, this beauty is finally finished, in the process I have changed:-

    118 Capacitors
    10 Resistors
    10 Trimmers
    11 Relays (9 signal relays and 2 speaker relays)
    26 Diodes

    I am just making final adjustments, and playing some test music, then it will be cleaning, re-installation of all covers, and more cleaning. ;)
     
  4. ghamilton

    ghamilton Super Member

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  5. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    And finally

    An underside view (minus right side wood panel)
    IMG_2359.JPG

    A topside view
    IMG_2360.JPG

    A rear view - to show replacement speaker terminals
    IMG_2361.JPG


    And a front view - top cover off
    IMG_2362.JPG

    Has anyone noticed that Sansui spelt 'Toroidal' wrong on the label for the mains transformer? - instead spelling it 'Troidal' :D
     
  6. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    And compared in size to an AU-717 :D

    Rear panels are lined up.
    IMG_2364.JPG
    IMG_2365.JPG
     
    Last edited: May 16, 2018 at 11:03 AM

     

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  7. Ronito6

    Ronito6 Super Member

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    Looks great!

    How did you clean the RCA sockets? The corrosion that develops there is especially difficult to correct.

    My method of dealing with it is rather brutal.

    I’m rather hoping that you have a kinder process than mine.

    My method:
    • Remove the RCA socket unit from the amp
    • Cut off an RCA plug from off a cheap, or broken RCA cable.
    • Attach that plug to a drill as you would a regular drill bit.
    • Fill the hollow of that makeshift drill bit with gritty type metal polish.
    • Plug the the plug / bit into the corroded socket and press that drill trigger.
    • After all sockets have been cleaned of corrosion wash the socket in soap and tap water to remove the polish residue.
    • Rinse in distilled water until water runs clear and all trace of residue has been flushed away.
    • Do a final rinse with 99% pure alcohol.
    • Allow to dry then reinstall the socket unit
     
    Last edited: May 16, 2018 at 9:04 PM
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  8. phonomac

    phonomac Active Member

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  9. SanthoshA

    SanthoshA Active Member

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    Really nice work John, i haven't started with the rear panel work yet, will surely need your support once i work on the same.
    Glad to see the amp is in nice condition and in good hands :thumbsup:!.
    And yes these amps are so massive in size, and moving them around in the work space up and down is a bit of a gym work out .
     
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  10. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Yes it is, I agree. I tried many things including 'liquid Brasso', 'Brasso wadding', also 'Silvo wadding' and and all purpose metal cleaner called 'Solvol Autosol' - intended for use on car metalwork. I even tried toothpaste, :) a mild abrasive, but this wasn't effective.

    What worked best for me was an overnight application of Brasso liquid, followed by Brasso wadding stuffed into the end of an appropriately sized 'nut spinner'.... (9mm)

    Nut spinner
    [​IMG]

    Then twist and twist until shiny and clean.

    The sockets on this one were badly corroded and some never came back to bright metal, but the thought of fitting replacement RCA's along with losing the 'shorting' capability of the originals, losing the internal RCA PCB's, and then maintaining correct ground paths for the rewired replacements seemed too much. I tested the RCA connectors and the resistance presented by the screens and inners after polishing and cleaning - and everything checked out fine.
     
    Last edited: May 18, 2018 at 3:00 AM
  11. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Thank you Santhosh, of course I will help you all I can regarding the rear panel work. The speaker terminals required a bit of thought, but it all came right in the end. I had chosen ones with a particularly small size of threaded shank, to avoid having to drill out the PCB connector plates too much. The actual speaker terminals turned out to be a bit smaller than I expected - but were still more or less the same size as the originals and required no drilling to fit. I did have to discard the supplied panel insulators and use 'trimmed' power transistor nylon insulating washers to occupy the original square rear panel speaker socket holes, and re-used the original internal plastic spacers. ;)

    I worked with the unit minus its heavy front panel most of the time, and with duct tape protecting the panel (especially the edges), when it was fitted to avoid workbench inflicted damage as much as possible. Nevertheless the unit is formidably heavy, especially dressed up with all its outer covers fitted, an easy 'two man lift' but (for me at least) a bit of a struggle single handed. ;)
     
    Last edited: May 17, 2018 at 6:27 AM
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  12. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    I delivered the X11 back to its owner this morning so we'll see what he thinks of it in due course. ;)
     
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  13. Ronito6

    Ronito6 Super Member

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    Yes, normally. I actually bought a Caig RCA cleaning kit with a proper RCA socket cleaner, but the fouling was so deep that it did little to restore them.

    The physical approach I used got them to shine. (Minus the nickle plating which was hopelessly fouled anyway.)
     
  14. MP984

    MP984 AK Subscriber Subscriber

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    I won't derail the technical discussions, but as the owner of this amp I just wanted to thank John for his sterling work. I took a bit of a risk on this amp when I bought it on Rinkya: it was described as 'junk', but X1s and X11s are as rare as hen's teeth in the UK (at sensible prices, anyway), and I bought it at a really low price. My theory was that if anyone could fix it then John can.

    As John mentions I collected it this morning, got back home and ran into a practical problem while trying not to give myself a hernia from carrying this thing. It was too wide for the bottom shelf of my hi-fi rack, which is where my vintage amps usually reside. I had to rearrange everything, which unfortunately was wasted listening time.

    Anyway, the photo below shows it in its new home, and also gives some idea of the size of the amp. It really is a beast, and I can imagine that working on it single handedly was not easy.

    I'm aiming to get some serious listening done in the next few days, but my wife's birthday is on Saturday and strangely she feels that my vintage hi-fi obsession is a lower priority..........................


    Sansui AU-X11.JPG
     
  15. Hipocrates

    Hipocrates Anti-Muppet

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    That's a happy amp right there, kudos!
     

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