Sansui AU-919 Black Flag Capacitors, Some help please

[sjackh]

Hey everyone, i just bought a Sansui AU-919 on craigslist and in need of some help. The guy said it was fully serviced, but I'm not sure if he is telling the truth. Can someone here spot if the Black Flags exist in this unit (see attached photos)?

Any help would be appreciated

 

[pete_mac]

The black flags are still in place on the PCBs visible in the photos, along with the original capacitors and other components.

'Serviced' is different to 'overhauled' or 'restored'. The amp could well have been serviced including setting the bias, DC offset, cleaning controls, testing functionality etc. Servicing will typically not include replacing black flag capacitors, and not all technicians will be across the issues regarding the black flag capacitors unless they are Sansui specialists or frequent forums such as audiokarma. Replacing the black flags in isolation is not particularly cost-effective due to the disassembly of the amp that is required to undertake this. Instead, the task is rolled into a complete overhaul process.

I don't think you could consider the seller to have lied unless you specifically asked whether the black flags had been replaced.

 

[sjackh]

The black flags are still in place on the PCBs visible in the photos, along with the original capacitors and other components.

'Serviced' is different to 'overhauled' or 'restored'. The amp could well have been serviced including setting the bias, DC offset, cleaning controls, testing functionality etc. Servicing will typically not include replacing black flag capacitors, and not all technicians will be across the issues regarding the black flag capacitors unless they are Sansui specialists or frequent forums such as audiokarma. Replacing the black flags in isolation is not particularly cost-effective due to the disassembly of the amp that is required to undertake this. Instead, the task is rolled into a complete overhaul process.

I don't think you could consider the seller to have lied unless you specifically asked whether the black flags had been replaced.

Thanks for getting back to me and teaching me some terminology. That being said, I heard those black flags can cause serious damage, is that true? if so, do you recommend replacing them right away?

 

[pete_mac]

Thanks for getting back to me and teaching me some terminology. That being said, I heard those black flags can cause serious damage, is that true? if so, do you recommend replacing them right away?

Personally, I'd recommend replacing them as part of a thorough overhaul of the amp to ensure reliable operation for years to come, but that depends on your budget.

I don't think it is cost-effective to dive into to the 919 to replace the black flags only.

 

[sjackh]

From your experience, what is the cost of a complete overhaul restoration?

 

[sjackh]

Personally, I'd recommend replacing them as part of a thorough overhaul of the amp to ensure reliable operation for years to come, but that depends on your budget.

I don't think it is cost-effective to dive into to the 919 to replace the black flags only.

From your experience, what is the cost of a complete overhaul restoration?

 

[pete_mac]

From your experience, what is the cost of a complete overhaul restoration?

Very difficult to say - costs vary across the globe. In Australia, you'd be doing well to secure a restoration of a 919 for under $600-700.

The key is to find a suitably experienced tech or hobbyist near where you live - not just the local audio repair shop (unless they happen to know their way around the 919 and can quote all of the work required off the top of their head).

 

[sjackh]

Very difficult to say - costs vary across the globe. In Australia, you'd be doing well to secure a restoration of a 919 for under $600-700.

The key is to find a suitably experienced tech or hobbyist near where you live - not just the local audio repair shop (unless they happen to know their way around the 919 and can quote all of the work required off the top of their head).

Im based in New York City, do you know any reputable 919 specialist? or know any members with this experience/issue...

 

[pete_mac]

Im based in New York City, do you know any reputable 919 specialist? or know any members with this experience/issue...

I'm in Australia so I can't help with recommendations. Hopefully another member can chime in here, and there are many other threads on AK seeking advice on techs in various locations that might turn up via the search function.

Good luck!

 

[sjackh]

I'm in Australia so I can't help with recommendations. Hopefully another member can chime in here, and there are many other threads on AK seeking advice on techs in various locations that might turn up via the search function.

Good luck!

Thanks for all the help

 

[Sansushi]

you might check with member @Leestereo

 

[Hyperion]

I heard those black flags can cause serious damage, is that true? if so, do you recommend replacing them right away?

Yes, their failure can lead to the amplifier becoming unstable, when that happens other components such as output transistors can be damaged or destroyed, and original replacements are extremely hard to come by.

Just to give you an idea of what's involved, I happen to be reconditioning an example of the Japanese Domestic model of the AU-919, called the AU-D907 right now and illustrating the process here on AK, there are several older threads illustrating the same process,
https://audiokarma.org/forums/index.php?threads/au-d907-for-restoration.980756/

Update: @sjackh
Here is a link to the thread which is now regarded (by me at least), as the 'Gold Standard' for AU-919 restores by AK member Leestereo.
https://audiokarma.org/forums/index...ration-and-upgrade-of-a-sansui-au-919.698011/

 

[sjackh]

Yes, their failure can lead to the amplifier becoming unstable, when that happens other components such as output transistors can be damaged or destroyed, and original replacements are extremely hard to come by.

Just to give you an idea of what's involved, I happen to be reconditioning an example of the Japanese Domestic model of the AU-919, called the AU-D907 right now and illustrating the process here on AK, there are several older threads illustrating the same process.
https://audiokarma.org/forums/index.php?threads/au-d907-for-restoration.980756/

Gosh, looks really complex. How long is this project taking you,if you dont mind me asking?

 

[Hyperion]

How long is this project taking you,if you dont mind me asking?

It takes me about 3 weeks to do the actual work, but I don't work on it 9-5, maybe work on it for an afternoon, or a morning, and often in the evenings for a couple of hours, and generally fit it in with domestic happenings. The preparation, deciding what parts I need and ordering them takes a few days. I order 90% of the parts for each restoration, meaning that I try not to keep electrolytic capacitors 'in stock' as I think it's only right to use the freshest parts for customer restores.

 

[LWB]

I would LOVE to find an unrestored, unmolested 919 such as sjackh has shown us. If it was mine, I would immediately do the full press refurbishment with new caps, etc. without attempting to put the amp, as original, in service. It will fail unless properly fully reconditioned.

 

[ivandezande]

The above. Pretty much every 919 I've seen or worked on has been messed with in some way because they always, always fail.

 

[sjackh]

I would LOVE to find an unrestored, unmolested 919 such as sjackh has shown us. If it was mine, I would immediately do the full press refurbishment with new caps, etc. without attempting to put the amp, as original, in service. It will fail unless properly fully reconditioned.

the guy that sold it to me said it was fully recapped and serviced....

 

[Sansuiman]

^ if this amp was sold as fully recapped and priced accordingly, you got ripped off. It is clearly and self evidently not re-capped, and in light of that, I suspect little else had been done to it short of maybe cleaning the controls and setting bias, if even that. A serious discussion needs to be had with the seller regarding the state of this amp, versus how it was presented pre-sale.

Provided the amp works, a price adjustment in your favor is probably in order. For any other circumstances or unwillingness by the seller to make good, I'd seek a refund in full, return the amp to the seller, and find a more honest transaction elsewhere. The only thing I'll say in deference to the seller is that based upon the pics, this amp hasn't been butchered by half assed repair attempts. Then again; the pictures do not show the entirety of the amps internals.

There is a lot of this going on now, and as prices have gone sky high, the incentive to run scams has increased right along with it due to the profitability involved in such deceitful dealing.

 

[LWB]

Without knowing what you paid, it's possible that you did OK, because an unmolested original is still a worthy amp to obtain - but not to use in its original state. Make no mistake, it needs to be completely, knowledgeably refurbished with new caps and such. Now you have an idea of what that will cost. Finding someone to do the job is not a trivial task. Be careful to find a good tech.

 

[Hyperion]

the guy that sold it to me said it was fully recapped and serviced....

That was quite wrong and an untruthful description, however, it may have been prompted through ignorance rather than deception.

without attempting to put the amp, as original, in service. It will fail unless properly fully reconditioned.

+1 Quite right, the AU-D907 I am restoring has only been powered on for fault finding and confirming the 'good' status of restored boards, and always powered on first time at least, with a DBT in use.