Ampeg project chassis cleaning

[Luthierwnc]

Hi Guys,

I just got a basket case Gemini II chassis. It is mostly there but was rode hard and put up wet. It has years of gunk, grime and that funky chassis smell that they all seem to get to one degree or another. It has a little rust and no mouse piss so I think it is at least worth a shot. I'd shoot a picture but it is definitely not amp porn) I love Geminis and have rebuilt a couple so I know my way around the layout.

The only other cases I've seen this filthy were total rebuilds (Hammond organs) so I just stripped them. I'd like to keep as much as possible on this build but really, really don't want to spend hours Q-Tipping individual parts and not getting them clean anyway.

Has anybody got any ideas on how to douche the whole thing out at once? Or even how to get the major stuff out of there in one fell swoop to make the detail work less arduous?

Thanks, Skip

[blown240]

I would probably start with a shop vac, and some low pressure compressed air. Blow as much crap out of it as possible then see where you are.

[Luthierwnc]

Did that. It is the greasy grime that's the problem. Every really old amp I've worked on had some but this thing is nasty.

I'll be replacing the cardboard filter caps so even getting it wet isn't out of the question.

Thanks, sh

[Phil_S]

In a well ventilated space, use 90% isopropyl alcohol in a spray bottle. Hose it down well. The stuff will evaporate quickly. You can use an old t-shirt as a rag for places that need elbow grease. It is not ideal, but it sounds like what you want to do and I think it is mostly harmless. The trick is to find a solvent that won't muck around with important parts and that doesn't need rising. Most things that come to mind are toxic or flamable, so be careful!

[Structo]

I have found that 409 cleanser can degrease things pretty well.
Be careful around any labeling or finish because it can harm some of those if you are not careful.

If you don't care about that kind of stuff and there aren't any transformers mounted, I have ran dirty things through a dish washer before with good results.

[dorrisant]

Motorola put out a bulletin about cleaners for clients cleaning the boards in their radios. They suggested to use "Scrubbing Bubbles" bathroom cleaner. I wouldn't believe it if I didn't see it in writing.

We used to go buy it by the case at the dollar store... Man they would look at us funny!

The stuff works surprisingly well to cut all of the crap left by contact cleaners and all of the crap that emergency workers of police officers could accumulate in their radios.

It won't take everything off (including component labels), but it will cut that elbow grease down to a minimum. It will not leave a conductive residue and is good to go a soon as it dries.

Try it... You'll see!

Use a directed.

Tony

[Structo]

I was going to say that but I couldn't remember what brand it was.

I have used that scrubbing bubble type cleanser in the kitchen when nothing else would cut the greasy grime.

As before try a little before going full hog.

[Prairie Dawg]

I would have never believed it myself but here it is.

http://youtu.be/OkWePqTfD14

You can buy anhydrous isopropyl alcohol at any auto parts store that'll sell you HEET in the red bottle. It's sold as gas line deicer along with the yellow bottle which is methanol. The anhydrous is a very good degreaser.

[selloutrr]

I dont fully understand, You are saying you want it look and work as new but it's distressed and you are to lazy to do it right? if you aren't going to do it right don't bother doing it. It'll only take more time in the end if you over look something.

since you can't get under all the components with it installed.
label it
gut it
clean it
meter the parts before you put them in including iron
order the parts you need
rebuild it

A full gemini restoration top to bottom should take you about 8 hours from start to finish.
take pictures and label well incase you take a break and come back to it.

CLR will clean the chassis in 30 seconds, and stubborn gunk use a 2000 grit wet sand paper and elbow grease or rough cloth. rinse and dry several times, if residue persists use alcohol to clean, polish with an old tee shirt.

only use water, or a deluted windex on the silk screening and rub very softly even dry rubbing will remove the lettering.

stubborn rust use a dremel polishing tool and concentrated CLR or industrial toilet bowel cleaner and a wire brush.

[selloutrr]

I would have never believed it myself but here it is.

http://youtu.be/OkWePqTfD14

You can buy anhydrous isopropyl alcohol at any auto parts store that'll sell you HEET in the red bottle. It's sold as gas line deicer along with the yellow bottle which is methanol. The anhydrous is a very good degreaser.

this works for most sealed PCB's and connectors.
however any paper caps or open (not sealed) pots will be destroyed. transformers will be subject to rust.

let dry completely before powering on.

[selloutrr]

NOTE: When using a compressor make sure it is not an oil compressor. they spray a fine mist of oil when you use them it's not good for electronics, of surfaces, i.e. faceplates.

Most large compressors use oil.

[boots]

We used to use Freon in a spray can when I worked in a Pioneer repair shop in the 90's. It's a great solvent and evaporates very quickly. However, I think it's illegal in most states now and you can't get it anymore.

Other than freon, the best solvents were alcohol and Windex. I think Windex can be corrosive, but it is good for removing sticky adhesive residues from labels, etc.

I wonder if hydrogen peroxide would be a good cleaning agent? Seems like it would fizz a lot of the gunk off. And it's cheap enough that you could just give the whole chassis a bath in it.

[Luthierwnc]

I'm not sure I explained myself. Here is a gut shot of the perp (and don't say I didn't warn you). In this light, the picture came out better than the subject.

A friend asked me to have a look at his vintage Bassman (see other tech post) and gave me this as a thank you. I would have done it for free and by the look of this, just might. At this point, I'd like to make an evaluation of whether it is even worth it. It would be nice to degunk it and see what I have to work with. Fixer-upper Geminis come cleaner than this for not a lot of money. BTW, the exterior isn't bad.

If I were committed to restoring this I'd just roll up my sleeves and rub like it felt good. In this case, I'd like to look at the teeth first.

Cheers, sh

[Prairie Dawg]

We used to use Freon in a spray can when I worked in a Pioneer repair shop in the 90's. It's a great solvent and evaporates very quickly. However, I think it's illegal in most states now and you can't get it anymore.

Other than freon, the best solvents were alcohol and Windex. I think Windex can be corrosive, but it is good for removing sticky adhesive residues from labels, etc.

I wonder if hydrogen peroxide would be a good cleaning agent? Seems like it would fizz a lot of the gunk off. And it's cheap enough that you could just give the whole chassis a bath in it.

R-12 is about the best electronic cleaner around for controls too but it hasn't been available openly for at least fifteen years. I was lucky enough to get three full cans of Channel Master Tuner Bath (R-12 freon) in an old radio shop that had closed in the eighties but that's long gone. The only thing that is remotely close is CRC QD contact cleaner which is nothing more than naphtha. Flammable too. Anhydrous isopropyl is pretty good too.

[Phil_S]

Maybe someone else here would like to have some fun with it? You don't sound like the Gemini is your idea of fun right now. Time to part with it?

If not, I don't think there's an easy way around it. You can't dunk it until you remove the pots and the iron. If you get that far, you are already half way there.

That's how I see the horns of your dilemma. Good luck!