Insulation for circuit board??

[Hirsch]

I just repaired an amp that had a bad capacitor that did some damage to the board (charred it real good...and deep

). I've cleaned up the damage (spent several hours in a chat room with the manufacturer walking me through the repair), the amp is working and has been stable for several days, and now I need to put some kind of insulating coating on the work. What product should I be looking for?

Thanks for your help!

 

[Gariver]

Hi Hirsch:

In the tube amp world, some wires are insulated with varnish. And if you need a thicker coating, you simply add on coats. Maybe this solution works for you.

 

[mlchang]

There is also something that a lot of computer tweakers use when using extreme cooling techniques to keep condensation from damaging the motherboard traces...I think it is spray-on conformal coating or something.

Conformal coating at contact east

 

[erix]

Are you looking for something to go *on* the circuit board or something to go *between* the board and the chassis?

ok,
erix

 

[Hirsch]

Quote:

Originally posted by erix Are you looking for something to go *on* the circuit board or something to go *between* the board and the chassis? ok, erix

Right on the circuit board. I had to leave a decent gouge to get all of the carbon out of it. There was some serious voltage running through that capacitor when it went. I had to run a jumper to replace a trace that was completely shot, and some of the remaining traces have small breaks in the insulation.

Gariver,

The varnish sounds like a good idea. This is indeed a tube amp (RKV).

mlchang,

The conformal coating looks like it will work as well.

Now I've just got to decide which to use.

Thanks!

 

[Wodgy]

Strange how so many RKVs bite the dust so quickly...

 

[Gariver]

Hi Hirsch:

I've got an RKV also. So I'm curious about the cap that malfunctioned. Do you mind telling me the value of that particular cap? Also: Is it a PS cap, or is it a Left or Right Channel cap? TIA for your answer!

 

[Neophyte]

I alway liked stuff called Liquid audio tape. I's a rubber liquid that you can apply and it will dry and insulate your wires. On my first cmoys I kept having issues mashing things into a to small box. during the massing I kept crossing wires so I applied liquid electraial tape to most of the board. It was ugly when done but it kept everything from shorting when being mashed.

 

[Hirsch]

Quote:

Originally posted by Gariver Hi Hirsch: I've got an RKV also. So I'm curious about the cap that malfunctioned. Do you mind telling me the value of that particular cap? Also: Is it a PS cap, or is it a Left or Right Channel cap? TIA for your answer!

It's a 4.7 uf 350 v electrolytic, manufactured by Yadeo. It's not in the power path, and its absence does not affect the sound (the replacement hasn't arrived yet, but the amp is perfectly usable). It's on the right (from the front of the amp), located just to the front of a 2.4K resistor. It's at the side. I'm debating whether to replace its counterpart in the other channel. Apparently those capacitors have been a major headache for AudioValve, as they have been failing abnormally.

 

[Gariver]

Hmm...is it a replacement 4.7uF--350v cap from Audio Valve, or is it a part from a audio parts vendor. If it is from a vendor, can you give me the proper details. I mean, those 350v caps are not easy to find. TIA for the info!

 

[Hirsch]

I ordered one from mouser.com, but it hasn't arrived yet. I forget the brand name, but I'll let you know when it arrives. Cost about a quarter, IIRC. As long as capacitance and voltage rating are right, I don't think it will affect the sound at all. If it turns out that it does, I'll get something from tubesandmore.com which has decent high voltage electrolytics. Partxconnexion.com has good electrolytics as well (I think there's a minimum order charge there).

There is an identical cap in the other channel, and I haven't looked to see if any of the others are the same value. Once you get past the first few days, the odds that the cap is bad go way down. I'm only going to replace the one that malfunctioned, and see how it goes.

 

[bangraman]

Have you heard about the problems with many Taiwan-sourced capacitors? Their main source of electrolytes were using stolen electrolyte formula from Japan which was missing some vital additives...
It's not very well made in Taiwan, is it