Vintage Chassis Cleaning -- What to use?

[Robert Technology]

Hello everyone!

A buddy of mine wants me to look at a vintage Fender Showman amp that he has with a blown power transformer, and it looks like the chassis has been covered with some of the transformer oil.

Any ideas on what to use to clean up this gunk? I don't have it in my shop yet, but he sent along a few pictures:



*edited to add that I was thinking the best solution would be to pull everything from the chassis, and scrub with a toothbrush and some degreaser, but honestly haven't had to deal with this before... Usually I just get spiders and dirt.

[The Dude]

There are tons of electronic component cleaners that would work. You want something that evaporates. I would start with that. Depending on how well the gunk adheres, you may have to go with a plan B. I use a product called "Blow Off", but there are many.

Not that it's relevant, but I don't see how a transformer could spew that much into the chassis. Are you sure that's what the gunk is from? It doesn't matter a whole lot. You gotta get it out of there anyway.

[Robert Technology]

There are tons of electronic component cleaners that would work. You want something that evaporates. I would start with that. Depending on how well the gunk adheres, you may have to go with a plan B. I use a product called "Blow Off", but there are many.

Not that it's relevant, but I don't see how a transformer could spew that much into the chassis. Are you sure that's what the gunk is from? It doesn't matter a whole lot. You gotta get it out of there anyway.

Thanks for the advice. Maybe it's time to grab some Caig big bath or something like that? I was thinking one of my bicycle degreasers may do the job, but I've just never had to clean anything this extensively.

I'm honestly not sure what the gunk is... My buddy got this old amp from his uncle, and he just wants some advice on fixing it (he's a technician and is definitely comfortable with high voltages - just never has worked on amps). He claims the power transformer was pulled at some point because it was bad, and told me that was what the oil was from, but i've never seen something this bad. Here's another picture, check out that bias board!

[The Dude]

Yep, that's where I'd start. I'm not saying it's going to get rid of everything. Hell, maybe not anything since I have no idea what that goo is. It looks to me like the amp was submersed in something. You might be looking at a complete disassembly and reassembly depending on what cleaners will accomplish. Again, the big bath is a good start. Turn the old boy on end and start hosing it down, and then reassess. Some tooth brushing and more particular cleaning will probably be in order. Another worry is, what do the backsides of things look like- those secret places you can't see without major disassembly? What about the conductivity of the eyelet boards? Is the gunk conductive? Has it soaked into the boards? Can it be removed from the boards? If and once you get the stuff cleaned out, you will (at the very least) want to take a hair dryer or heat gun to the boards and try to dry them out.

[Robert Technology]

Thanks for the confirmation!

I really didn't think it was going to be this bad from what he was saying, but upon looking at these pictures it looks like a mess! At the very least that bias board will need to be rebuilt... now I'm wondering how coated the tube sockets are, and as you pointed out the eyelets on the board. I haven't made any promises to the guy, and he was the one who was going to be doing the work (or in this case dirty work), so once I inspect it I'll advise him from there.

Thanks again for the second opinions!

[g1]

Maybe restaurant/bar grease/nicotine? I think your buddy may be confusing amp transformers with the electrical utility type. Those are oil-filled, these are not. The worst that happens with these is that the varnish melts and a bit oozes out. I've never seen any beyond the immediate vicinity of the fried transformer.

[The Dude]

Yes, it sort of reminds me of the kitchen floor at a Long John Silvers.

[Robert Technology]

Maybe restaurant/bar grease/nicotine? I think your buddy may be confusing amp transformers with the electrical utility type. Those are oil-filled, these are not. The worst that happens with these is that the varnish melts and a bit oozes out. I've never seen any beyond the immediate vicinity of the fried transformer.

Thanks for the heads up! I felt like my inexperience with transformer failures was showing when I was surprised about him claiming that it was transformer oil... I was honestly hesitant to post about it for that reason, but am glad I did. I'll try to find out what kind of gunk it is.

It does look like areas nearer to the transformer are more affected (like the bias board), but without looking at the thing first hand it's really hard to tell whether the gunk is

[Leo_Gnardo]

I've seen this in lots of amps where PT's, OT's or chokes have fried. Brown/orange-yellow CrudŽ plated onto the metal, mostly near the transformer. I don't know which is worse, the probably toxic CrudŽ or the definitely toxic solvents you'll need to dissolve & remove it: good ol' fashioned acetone is certainly worth a try. Maybe trichlorethylene if you can get some. Electronic sprays called "Flux-off" might also work, they're strong solvent mixtures. Lots of ventilation, no sparks or flames nearby, try not to get any on you. Scotchbrite pads may help the scrubbing off process.

I've never made a practice of cleaning this kind of CrudŽ off amps I've found it on. It seems to be harmless though unsightly. Never noticed it caused any electrical leakage on eyelet boards or tube sockets.

[olddawg]

Do you want to fix it or restore it? If I owned it. I would take a ton of pictures under bright light before I started. The I would disassemble it down to the bare chassis. The chassis I would let soak in a tub of whatever solvent works on it, covered, in the middle of my back yard for a few days. Could be anything from alcohol to carberator cleaner. Whatever you find dissolves the stuff. All the hardware soaks in a coffee can. Boards and stuff you have to access individually. A sonicator might be helpful. Lots of stuff can probably be cleaned up with a rag and alcohol. Wear gloves. Don't smoke. Soaking in Windex sometimes works very well too. And yeah blow dry it or use a fan tent.

[Robert Technology]

I'm really not sure at this point whether the guy is looking for a restoration or to just get it running. If it were my amp I'd just pull everything out of the chassis and salvage what I could, but it's not mine!

I did get some more info from my friend about how it got this way:

No spills.
25 years ago, the last time this was on, I had come into the jam room and the whole room was waist-deep in settled smoke and that really acrid, rank smell of burnt electronics.
We each flicked on the power to our amps one at a time, both guitar amps lit up and when I went to flip my switch I realized it was already in the ON position.

My guess is, I had forgotten to turn it off the day before and it overheated/shorted overnight. Hence the smoke that was already settled but also why it made such a huge mess. It just sat there burning with no one around to disconnect power.
Back then there was no google so I pulled it out and attempted to scrape some of the spooge off but that's as far as I got.

I always thought it was the melted coating of the winding wire. Whatever that was at the time.

So... sounds like the gunk could just be some melted insulation from other wires/components, but this is now sounding like he probably burned out some other components with a catastrophic failure. I'm definitely going to lean towards giving him advice on how to fix this up (since he's technically proficient in working safe and knows how to solder well). I'd rather avoid spending hours scraping "spooge" if I can!