What is this brown stuff, and how to clean?

Hi
I was asked to take a look at a pair of Vincent SP-991 amps. Both are dead. That is, no sound, but relay kicks in, and no DC on the outputs.
After some time fiddling with how to take it apart ( no fun task ), I discovered that one of the pcb's ( the input stage on the bottom ) was totally covered in some
brown goo'ish stuff. It is quite sticky. I first thought it might be a leaky cap on the other pcb on top of it, but no. The top pcb is clean.
It is all of the pcb that looks like this, not just a small spot, as if the pcb itself has been sweating, could that be the case?
The way it is build does not allow for air circulation for this pbc. No ventilation holdes around it or on the pcb on top of it.

Sadly i forgot to take pictures before I started to clean. Here are a few images after cleaning round 1

What could this stuff be? and how to clean it ? The caps dont look bad. The goo isnt concentrated around the caps
The other light brownish goes off when using ordinary pcb cleaner and qtips
 

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The owner should know unless he bought the amp second hand.
This doens't look good and I for one wouldn't attempt a repair to have the amp returned after a few days or weeks.
Strange stuff, never seen... perhaps Westmalle beer. 😉

Hugo
 
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I dont think something was spilled into it. The rest is pretty clean. Also there is no way anyone could spil anything, because it would have to hit the pcb on top of it, but that is not the case. The other amp seems to look the same, although I havent taken that one completely apart yet
 
I dont think something was spilled into it.
Maybe, maybe not... but something has got in there.

It all looks very like atmospheric pollution as far as its possible to tell in a picture. I have seen it many times. Used in a room with coal fires and/or a heavy smoker. Its really gungy gooey stuff usually that doesn't just rinse off.

Liquid contamination usually shows signs of 'fretting' around PCB traces and component legs due to electrolysis and often there is a green Verdigris look to it.
 
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Whatever it is, it looks horrible 🙂

If it is nicotine/tar it will not just off wash off with water. Before you do anything see if it is conductive on a really high ohms range.

As for cleaning, I would use hot water and detergent. If it water soluble then the boards should come up well. I can see all the gunge on wires and plugs/sockets though... I still think whatever it is could be something environmental. Has it come out of a kitchen somewhere with a lot of cooking going on?

https://www.diyaudio.com/community/threads/washing-an-amplifier-board.301813/post-4942703
 
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I have gotten PA and background music amps from restaurants, covered in grease inside when they are anywhere near a kitchen.
The white smoke coming from fryers, ovens and grills or burger hot plates is just so much evaporating grease which will condensate on nearby cold surfaces.
PCs belonging to heavy smokers are often covered in a brownish goo.

Don't start me on roach and spider nests, mouse pee and poo and similar delights 🙁
 
take a look at edge od housing (2nd picture it is covered in same stuff) this could easily grow into full dismantling/desoldering task.... I personally would not attempt to 'repair' it for someone else as it would possibly require stripping everything from PCB 🤔😵
 
Hi
I was asked to take a look at a pair of Vincent SP-991 amps. Both are dead. That is, no sound, but relay kicks in, and no DC on the outputs.
After some time fiddling with how to take it apart ( no fun task ), I discovered that one of the pcb's ( the input stage on the bottom ) was totally covered in some
brown goo'ish stuff. It is quite sticky. I first thought it might be a leaky cap on the other pcb on top of it, but no. The top pcb is clean.
It is all of the pcb that looks like this, not just a small spot, as if the pcb itself has been sweating, could that be the case?
The way it is build does not allow for air circulation for this pbc. No ventilation holdes around it or on the pcb on top of it.

Sadly i forgot to take pictures before I started to clean. Here are a few images after cleaning round 1

What could this stuff be? and how to clean it ? The caps dont look bad. The goo isnt concentrated around the caps
The other light brownish goes off when using ordinary pcb cleaner and qtips
I would rinse it off with water and dry it in a dish rack. It does look like soda pop if you have issues cleaning it, place it in the dishwasher with dish washing soap, then redo the heat sink grease /pad.
 
I once worked at a company that produced video projectors and they used a Lady Kenmore
dish washer to clean the flux from their boards.
Although the did have a deionization system before it.
I also had a background music tape player back in the late 70's that was caught in a
California mud slide, packed completely with dried mud when received for service.
After taking off the covers I took it outback and cleaned the insides out with a garden hose.
Affter 3 days sitting to dry it worked again.

Water does not hurt if it is not powered and you let it dry.
 
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Thanks for all the tips. I haven't looked at the other channel yet a lot, as I got that going again by "working" the signal switch while spraying cleaner into it. But it felt the same as this one (sticky), which by the way also works again. The caps look good, but we are going to recap it anyway.

Happy that no parts are broken. It uses 2sk170 amongst others.

Merry christmas everyone
 
Hi, an old thread, but I would very much like an update on this, if #Onemangang sees this. Hope you got it sorted out. I have a pair of Vincent SP-991Plus. They dont have this goo inside. They are more than 20 years old, I bought them as brand new in 2003. One could call them the "Krell-killers".