Sansui 20000, most common original parts that defect except for common replaceables

[barstema]

Hello,

My is Bart I live in Holland.

I am a Sansui lover ever since I heard one and directly understood the difference.

I think they are one of the most musical amplifiers out there.

Because I want to keep Sansui as long in my world as possible, I would like to know how.

Me is not an expert in electronics but I understand that thing where out.

Recently I sold my AU9900A and AU555 because I am going to pick up my au20000 on Saturday.

I can’t wait to be honest!

But think I will mis the volume control on the au9900A.

I understand that the AU20000 is more rare.

So, I would like to know what spare past to by in front to keep playing as long as possible.

What are the most common parts that wear out and defect except and for the replaceable common components like diodes and capacitors ??

What is a no go, what should I look for when picking up the au20000.

Many thanks,

Bart

 

[dsmart705]

Im not sure there is anything on the AU20000 that is difficult to find modern replacements for. It is a big job to rebuild if you want to do some preventative maintenance and is going to involve lots of labour. I recently finished restoring mine and the parts cost was around $150cdn which did not include the main filter caps but did include most other things. I would expect to pay in the $400-$600 range to have a professional tech do the work including the parts.

What to look for really depends how technical you are able to get but a simple offset check might be a good idea. Checking the bias on these involves removing both top and bottom covers and is a very finicky procedure (need a steady hand to avoid sparks) but there is nothing really that special on the 20000 compared to any other Sansui integrated amp. Some of the earlier ones have large resistors on the driver boards which can cause heat damage and there are no fuses to protect the transformer. Good luck if you end up buying one, hopefully it will be in good condition.

 

[JoshHendi]

Be warned, the AU-20k has quite a few potential problems, and had many 'adjustments' by Sansui through its production run, so dont count on the service manual being 100% accurate...

The 'passthrough' boards that are mounted between the heatsyncs, those MUST be addressed, and honestly, I'd start there, as that board can cause many issues that seem like the problem is coming from elsewhere... Get those passthroughs addressed first so you dont have to worry about them causing any random issues (and preserve those 12 precious outputs)

The 2SC984 bias transistors on the later models are failure prone and there are no exact modern equivalents, but NOSs are out there, but can also use KSC1815 in a pinch if needed

As far as caps, diodes and transistors, there are good modern equivalents out there for this amp... The thermistors in the passthrough board are hard to find, but are rare to fail unless there was a massive failure (and I have some NOSs if you happen to need them).

If you opt to replace the outputs and large filter caps, that is already $150 in parts right there.

Plan on a $200-250 budget for restoration parts (I know thats crazy)