• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Sansui AU-11000 Restoration Attempt

Will_Emanuel

Will_Emanuel

AK Subscriber
Subscriber
Hello all, new user here, sorry if I don't get the formatting quite right. I'm currently starting on a full restoration and recap of my newly acquired Sansui AU-11000. It's had a rough life, with a previous tech who, for some unexplainable reason, cut off almost all of the easy to disconnect molex connectors in the unit and directly soldered the leads to the connector pins. It is still fixable, I'll just try and see if I can't source some of them to put back in the unit. Anyways, this is where I am at the moment. The entire unit is completely disassembled, I've documented most of the boards and their current state in the photos below. Filter caps appear to be ok physically, I'll look into them more when my ESR meter arrives later this week. This is my first full restoration, so any advice would be super helpful. I've done a few recaps on easier to work on units like my Sansui 990DB, but nothing as comprehensive as this. Due to the lack of threads that I was able to find on a restoration of this unit, I hope this thread will be useful to others in the future.

2iV00Z9.jpg

Here's the unit before teardown, cleaned up pretty well.


S5FA86z.jpg

Quick photo of the underside of the unit. You can see evidence of the botched repair in the top of the photo on one of the tone boards, as well as on the connectors on the driver board in the bottom left.


jqnraYs.jpg

further documented evidence of the missing molex connectors.


mXYvKOE.jpg

Here's the F-2568 Power Supply board, all electrolytics will be replaced here.

Aah5uP9.jpg

F-2582 Protection board. Two large caps on the right bulging quite heavily. All electrolytics here will be replaced as well.

CAFiGDm.jpg

F-2583 Driver board. Looks ok, no heat marks anywhere. Electrolytics will be replaced, are there any fusible resistors on this board that need to be replaced like there were on the 990db/9090db?


wK8p3Wj.jpg

F-2566 Power Supply board. Looks to be in good shape, I'll check the diodes and fuses before this guy goes back in.


Viv42Dw.jpg

F-2570 Input/Phono board. All electrolytics will be replaced here, any other parts that should be replaced?


Xf4B4qR.jpg

More missing connectors on F-2576 and F-2578 Tone boards. Electrolytics will all be replaced on these boards as well.

if503XJ.jpg

Current state of the unit. All pots and switches have been cleaned with deoxit.

Currently waiting for all the new caps to come in. Any recommendations from fellow owners who have rebuilt their units would be greatly appreciated.
 
Register to hide this ad
FWIW, it appears that the connectors are still there, it's just the plastic connector housing that is missing, and of course the connectors soldered to the board.

Most of those connectors from that era are berylium-copper with a tin-plating, should tolerate the heat necessary to remove solder from them but I would avoid annealing them by overheating, at that point there's no strength left and they will never have good contact pressure. Best of course to find new if you can.

Also, is that a notch arc-burned into one of the exposed Molex pins on the driver board or just an illusion in the photo?

As far as rebuild threads, there are some very good ones on this amp & the AU-9900, which share the design and several of the boards, not a bd place to reference. One of these days I'll get around to putting my AU-11000A on the bench, I still listen to it daily in my office / all original, ... one of these days.
 
I just restored my AU-9900. Some details in a thread here. No fusible resistors on the driver board that I was aware of. I did change the trimmers. I also replaced D05 and D06 (SV-02) with series pairs of 1N4148 diodes. That made a big difference in some background static I was hearing before replacing them.

Pretty sad about those connectors. Can't imagine why anyone would do that. :crazy:
 
Although it seems to be a common occurrence on here to find that connector butchery, I think this was done by some misguided tech in days gone by, and this was never done by Sansui themselves, 'laid on' joints, not even wound round the terminals - never in a million years. ;)
 
Last edited:
Man I've seen that kind of connections on several x0x0, x0x0DB,2 BA5000 and AU definition series to the point that I was sure it was done along other practices to cut corners. But is ok, if I'm wrong... I'm wrong, I still like my sansui VERY much.
 
Last edited:
Hipocrates said:
Man I've seen that kind of connections on several x0x0, x0x0DB,2 BA5000 and AU definition series to the point that I was sure it was done along other practices to cut corners. But is ok if I'm wrong... I'm wrong, I still like my sansui VERY much.
Click to expand...

Maybe it became a "common" repair to customers' Sansui equipment when a particular unit was noisy, if contact resistance / corrosion became more common. Much like a Service Bulletin, which maybe was misunderstood by some Technicians.

I can see where removing the connectors from the plastic connector housing, plugging them on the pins individually, then adding solder to seal them would make some sense if there were problems with the original design.

I do agree with John that this doesn't seem like something that would be done by a factory. If they wanted to solder they would have either crimped on pins to go in the original header holes and solder, or otherwise made a good mechanical connection to be soldered. However, I also agree that if this seems to crop up enough, from different areas to rule out a single shop doing this work, there must have been a common source for this modification and the most likely source would be Sansui (if pre-WWW).
 
KeithD said:
I just restored my AU-9900. Some details in a thread here. No fusible resistors on the driver board that I was aware of. I did change the trimmers. I also replaced D05 and D06 (SV-02) with series pairs of 1N4148 diodes. That made a big difference in some background static I was hearing before replacing them.

Pretty sad about those connectors. Can't imagine why anyone would do that. :crazy:
Click to expand...
Great. Thanks so much. Do you happen to have the up to date BOM on the parts you ended up using?
 
Sent PM. I also watched this guy's three part re-cap videos for his AU-9900.


He doesn't replace anything other than e-caps, and did not replace the filter caps, but it gives you an idea of the process. You have yours apart already, so the videos may not be that helpful for you, but I think they help if you've not taken one of these apart before, or getting them back together if you forget something. He also doesn't use a DBT, which is a big mistake. He got lucky he made no mistakes replacing parts.

Let us know how the yours goes!
 
Funny thing is, when I was a real repair Tech at a stereo shop/dealer some 40+ years ago, ... we never had any such thing as a DBT. Other than running a variac for setting exact supply voltages, pretty much all repairs were tested at line voltage. I never had a problem, but checked everything before powering up.

I can say that today, when I am working on my own gear servicing and restoring as a hobby, I would not ever power up without my trusty DBT creation, even when using the variac.
 
SaturationPt said:
Funny thing is, when I was a real repair Tech at a stereo shop/dealer some 40+ years ago, ... we never had any such thing as a DBT. Other than running a variac for setting exact supply voltages, pretty much all repairs were tested at line voltage. I never had a problem, but checked everything before powering up.

I can say that today, when I am working on my own gear servicing and restoring as a hobby, I would not ever power up without my trusty DBT creation, even when using the variac.
Click to expand...

That's the difference between paying for your mistakes out of your own pocket to having the company pay for your mistakes.

I remember losing a screws inside one of the big 9 track tape decks I used to work on at DEC. The power supply was open and right below the tape assembly, and if you couldn't find the screw, you closed your eyes and prayed there was no short when turning on the power breaker. I was always lucky, but it was a bad design. There was no way of moving the chassis and shaking the screw out. These units were about 500 lbs and as big as a fridge. If this were to happen on my dime, I would be stripping things down to find that screw before powering up.
 
Got an update for you all, Caps arrived and have been installed. Amp board, protection board, power supply, as well as the tone boards all got Nichicon FW and FG caps and MUSE ES bipolars.

p7lafCC.jpg

complete amp board
ARQKGFp.jpg

Power supply all done.
qZNhwrn.jpg

Protection Board received caps and a new relay.
FXqsln1.jpg

Phono board with new electrolytics.

After the new caps were installed, I reassembled the amp to see if my original protection issue remained. Well good news and bad news, it clicks out of protection, then clicks again and a lovely plume of smoke comes out of a resistor on the amp driver board. I went through and tested all output transistors as well as all transistors on the driver board with the exception of the 4 that are mounted to the heatsink at the bottom of the board, and all seem to test fine. If any of you have an idea on where to go from here, that would be much appreciated.
 
You must log in or register to reply here.
Back
Top Bottom