dirty dusty amp chassis and circuit.

[mike_mccue]

I have a mid seventies Silverface Super Reverb that was put away broken and stored poorly.

It's always been cool and dry so there isn't a bunch of corrosion or such but the chassis wasn't mounted in the cabinet so it's full of dust.

I'm going to do a complete electrolytic cap job for starters... after I clean it up enough to work on.

Any thoughts on how to best clean the dirt out?

Especially with regards to the waxy residue on the circuit board.

thanks,
mike

[Rob Mercure]

Mike,

Here in the Central Appalachians I've had occasion to clean several amps that were in floods and I can tell you that washing out the amp in a sink under running water and immediately putting it into a 120 degree oven with the door cracked over night won't hurt the amp - but make sure that it's only "baked" at 120 degrees and that the baking goes on for at least 8 hours or so. This will get rid of all the dust and debris and may even melt off the wax (but I' probaby not count on it at that temp). Afterward - or first, probably isn't that important - you can melt the wax off with naptha or isopropyl alcohol. The naptha (cigarette lighter fluid) is of course flammable. The alcohol is also but not as much. I you're going to flush and bake then common 70-90 percent rubbing alcohol will work. If you're not going to bake then 99% water free alcohol is recommended. Don't use naptha and bake as the flushing might fail to remove pockets of naptha <boom!>.

If you've got a lot of minerals in you tap water do a final flush with distilled water before baking.

Rob

[Enzo]

I agree that electronic components are not afraid of water when ther is no power present, but that seems like overkill for dust.

SOme folks like to blow it out with air pressure. It fills the shop air with dust I then have to breathe, plus it then settles on everything. I prefer a shop vac with a hose. I suck the dust out. I have a couple cheap paint brushes - like a 1" and a 3" - to loosen the dust. Hold the hose over the brush.

I agree you can use solvents for that waxy stuff, but is it conductive. If it hasn't gone conductive on you, I tend to ignore it.

[mike_mccue]

Thanks to both of you for taking the time to answer and offer opinions.

I did know that lots of electronic circuit boards are bathed at the fab houses... but I was worried about things like the trannys and potentiometers.

I guess I start the smart and easy way with a vacumn and see if I can proceed with that.

If that doesn't work I'll bathe it and *bake* it in my mini van parked in the sun. Our gas oven doesn't have thermostat that will stay steady down at 120* :-)... and I hate to think what could happen.

thanks again,
mike

[Rob Mercure]

Don't use the mini-van - every kitchen should have an oven thermometer anyway so buy one. My recommendation for the oven isn't casual as any remaining water is a guaranteed to provide a short circuit. Baking in the oven is a sure thing and the temperature isn't "life or death" only that it is steady and for a long period of time. 100 degrees F is probably fine but I wouldn't trust a car unless you're in Death Valley in August <grin>

Rob

[mike_mccue]

I appreciate your concerns about my safety.

But thankfully, the chassis cleaned up vey well with a vacumn and a paint/dust brush. I did a final compressed air blow out to finish off. It's almost as if the dust was protecting the components... I guess cool and dry was the determining factor.

We have a oven thermometer... but the oven doesn't have a functional thermostat. We bought it new in the 1993... the built in thermostat died almost immediately... and several service techs told us the part was unavailable :-0.

So much for that... I'm not gonna rag on technicians being less than able... in a roomful of technicians... including myself!

While I continue to be flabergasted about that, we just live with it because we only use the oven for short run cooking and the range works great.

I do have kilns but there designed for apprx 1000*f long runs.

I'm starting a new thread about the amp.

best regards,
mike

[capnjuan]

Hi Mike: I've had good luck with isopropyl alcohol and que tips; can flood the pcb, mop with que tips and get 90% of stuff off. When dry, the reside is pretty easy to displace with stiffish paint brush. John

[mike_mccue]

Thanks John,
I've used alcohol to clean up flux residue in the past. It seems to work real well.

best,
mike