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Sansui frenzy in the lab this month

Discussion in 'Exclusively Sansui' started by kevzep, Oct 29, 2018.

  1. kevzep

    kevzep Its all about the Music Subscriber

    I would have liked to do a thread for each of these Sansui's, but time is not on my side, so here's a brief overview of whats been and about to be across the bench lately and soon...

    I had a G6700 in for tuner issues, no quartz lock, and weak reception, also unit was "humming".
    I simple turner alignment brought this one back to full operation.
    The humming was caused by the Dreaded Glue!!! The F2980 was infected with the glue and quite severely.
    three of the Capacitors just fell off!!
    Many of the caps were well out of spec and a few were shorted/leaky...
    So after we recapped the board and meticulously removed the glue we were good to go!! New relay etc etc
    This one came up well and the customer was a happy camper!!
    So the GX700 series needs to be checked for this glue disease...
    IMG_6824.JPG
    I went through a customers AU999 and god rid of those Green Blob caps....This one along with the Differential mod came up nicely too and sounds immaculate....it has the full compliment of mods...
    IMG_6861.JPG IMG_6863.JPG
    Then I did a tuner alignment on this G7500, it could barely receive a station at all, and not at all with the FM Muting switch in, a full alignment brought it back, the tuner Sansui used in this model is actually really good, it has great sensitivity.
    I also blew through the F2980 board and recapped that as the glue was about to consume everything in its path.....
    IMG_6915.JPG
    Then I am also doing a recap/restore on this AU777A, a nice clean unit which belonged to the owners father, he bought it on an overseas trip in 1969 I think he said. Its a little easier to work on than the non A variant, pre-amp is laid out better and not so many point to point power supply connections....
    This should come up nicely.
    IMG_6944.JPG IMG_6943.JPG IMG_6941.JPG
    Then I have another G6700 which has a display driver chip issue, and it also has a front end issue in the tuner, courtesy Ghazzer and the AK connection, I was able to get a MSM5540RS which is in transit, and also this one needed to have the F2980 recapped as well because of that glue!! Again!! The glue!!
    So this is waiting for parts and should be out of here soon....
    Then yesterday, I picked up this QRX9001 to go through and get working, it has channels dropping out, bulbls blown etc etc, so this one will take a while to do, but having done two others I have it down to an art now...
    and that wraps up the Sansui activity going on in my lab...Pretty funny looking at the QRX9001 on top of the SX1250!!
    IMG_6951.JPG IMG_6949.JPG
     

     

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  2. damacman

    damacman Blown and Injected Subscriber

    Messages:
    8,614
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    Nicely done kev!
     
    jobrewer1983 and kevzep like this.
  3. KingBubba

    KingBubba "Too Much Stuff" Subscriber

    Messages:
    9,917
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    Brooksville, Fl.
    Years past, I decided against buying a 9001 for $35. I was just too big to be believed. Sure is pretty though.
     
    slimecity likes this.
  4. slimecity

    slimecity Super Member

    Messages:
    3,000
    Location:
    New Zealand
    Nice one Kev - look at all those new red polys in the 999!

    Would you say that you noticed an audible difference after doing this?

    I gotta say I did notice this in my little 555a tone control board after following Leestereos' mods.

    If so, is there a particular series of WIMA to order (to ensure that they fit in the PCBs OK?)
     
  5. stereofun

    stereofun Super Member

    Messages:
    1,257
    Location:
    Tucson, AZ
    Yes, nice with the WIMA's are those the polypropylene or polyester ?

    Also curious to hear what the 777a sounds like on your rig, it supposedly have a tad more power than the non A - as much as I love the 999, it always floors me how good the 777 can sound, being single rail, cap coupled, High THD, low lamping factor and they don't even sport a single PNP.
     
    slimecity likes this.
  6. kevzep

    kevzep Its all about the Music Subscriber

    Polyester Film those ones were....

    I think the sound might have cleaned up a bit, there seemed to be better instrument separation, deeper soundstage....

    When I restored that other AU777, I was completely amazed at the sound of that little amp, it was so impressive...
    I am looking forward to listening to this one once I get it done.

    @slimecity I just pay attention to the lead spacing, certain variants have different lead spacing, and then sometimes you have to go up in voltage.
    Its a bit of fiddling around on the mouser site, but there's always something that fits.
     
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  7. kevzep

    kevzep Its all about the Music Subscriber

    A bit more progress on the 777A, getting through the recap....transistors coming out and new ones going in, although I am not sure if I will change the power amp ones, I will see how it runs first before I go there. Always good to change the pre-amp transistors with all the gain that goes on in there

    I quite liked these caps, Nichicon have so many good options for caps to fit the original clamps....

    IMG_6973.JPG IMG_6974.JPG
     
  8. pete_mac

    pete_mac Super Member

    Messages:
    2,834
    Location:
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    Agreed Kev - there's a great variety of sizes in the KG range.
     
    kevzep likes this.
  9. ghazzer

    ghazzer Senior Member Subscriber

    Messages:
    3,001
    Location:
    Sykesville, MD
    I think I'd enjoy a trip to NZ if I could sit in your lab and watch you for a week.

    I spent a day with Overundr1in his shop and was amazed at how rapidly he went thru things that I might futz with for days.

    If I could remember 10% of the things I have learned in the last 50 years I would be amazed.
     
  10. jobrewer1983

    jobrewer1983 AK Subscriber Subscriber

    Messages:
    9,527
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    San Jose, CA
    I ran a 1250 for a few years, was a good amp. Never got to see the 9001 on top of one, cool pix and great thread!
     
  11. kevzep

    kevzep Its all about the Music Subscriber

    That 1250 is a customers, but its been with me for a while now, its had a very thorough restoration and its got to be one of the best around.
    Its a nice amp, but doesn't quite have the sophistication in the sound that the Sansui's do.
    Funny how the QRX dwarf's it!!

    I think you probably would Steve, I could use a Lab assistant sometimes!! You are welcome any time!!
     

     

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  12. Glenz75

    Glenz75 Sansui and Pioneer Freak

    Messages:
    780
    Location:
    Wellington, New Zealand
    Wow Kevin, you have been a busy boy! I love the complete rebuild on the AU-999 that looks super sweet!! With those Wima caps in there should sound even better. The good old QRX9001..I have just had an 8001 in from a customer who brought it off the original owner that had me service it back on 2012. This time it was intermittent 4 channel operation which turned out to be the double sided print on the surround mode switch PCB had to re-solder everything joint/trace connector on there to cure the problem. A real PITA it was as well, but all fixed and the customer is super happy with how it performs now. I have a couple of AU777A's they do sound nice those old things :)....
     
    BLAH BLAH likes this.
  13. kevzep

    kevzep Its all about the Music Subscriber

    Yep there's been a lot happening...
    The QRX9001 is going to be a big one to do, I'll need a few free days for this...I'll be doing the passthroughs for sure on this.
    I am looking forward to hearing this 777A when its finished....
     
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