Anyone know how to remove rust from amplifier circuit board.

[theokalat]

Hi,

I have a Yamaha MX-1, and after looking closely at the circuit boards, after removing for a general cleaning and dusting, I noticed there are many solid wire resistors,some are gold coloured, and others are silver coloured.

They don't look like normal resistors, but rather just straight wire connection end to end.

Only the silver coloured wires appear to be rusted or oxidised. Seems to be surface rust or oxidation only, as I have succesfully scraped the rust off on one of them, and it came off, but took a while.

But all the others are also rusted, so my question is, what is the best way to remove this rust easily, and afterwards, is there something I can apply to prevent further rusting down the track, assuming these are resistors, which means they probably get hot, so I would assume some sort of special coating would be needed which is flame proof also.

Anyone have any good suggestions.

My second problem is probably also similar to the above, the two top sides of the outer casings on the transformers were also rusted ( I think they are alumina casings), but only surface rust, I sanded it all off, but now need to have the cases coated with something that can withstand extreme heat ( they get very hot) to prevent further rust reoccuring down the track.

Again, does anyone have any solution for this.

 

[avionic]

I noticed there are many solid wire resistors,some are gold coloured, and others are silver coloured.

They don't look like normal resistors, but rather just straight wire connection end to end

Thats probably what they are is just a jumper wire.Rather than clean the oxidation I usually just replace the jumper wire.

 

[theokalat]

Thats probably what they are is just a jumper wire.Rather than clean the oxidation I usually just replace the jumper wire.

Can they be bought or do you just use any strips of wire cut to size, or does it matter on the size and type of material used.

 

[Kerb]

Find a shop with a glass bead blaster. Some do it yourself auto shops have them. Turn down the air pressure to about 40 psi, and use some fine glass bead, or corn cob media. After blasting, spray with an electrical grade air-dry varnish.

 

[avionic]

Just replace the wire with piece of single strand of scrap wire or maybe use the trimmings from a cap or resistor lead.

 

[Goodwill_HiFi]

Find a shop with a glass bead blaster. Some do it yourself auto shops have them. Turn down the air pressure to about 40 psi, and use some fine glass bead, or corn cob media. After blasting, spray with an electrical grade air-dry varnish.

You'd seriously use glass bead on a circuit board? I've never used corn cob, but I'd be leery of using it on a circuit board too. I wouldn't want to rip up the fiberglass, or traces. I'd try an acid before I used an abrasive.

 

[Kerb]

You'd seriously use glass bead on a circuit board? I've never used corn cob, but I'd be leery of using it on a circuit board too. I wouldn't want to rip up the fiberglass, or traces. I'd try an acid before I used an abrasive.

It won't rip up the G-10 board, but it might damage the traces. Glass may be too abrasive. Corn cob is very gentle. Air pressure would need to be below 40 psi, and you would need to feather the board.

I blasted circuit boards this way with no problems. (Generator voltage regulator boards). Not the traces though. It helps when the glass is very fine.

 

[jimbofish]

My second problem is probably also similar to the above, the two top sides of the outer casings on the transformers were also rusted ( I think they are alumina casings), but only surface rust, I sanded it all off, but now need to have the cases coated with something that can withstand extreme heat ( they get very hot) to prevent further rust reoccuring down the track.

Again, does anyone have any solution for this.

Engine paint should be more than sufficient for this. If you're really concerned, bar-b-q grill paint is good up to around 1000 deg. but IMO, if it's getting that hot, you've got bigger problems to worry about than rust... like melting components!

 

[asmd]

my yamahas transformer has rust on it too.. i too would like to know how to treat it to prevent it from trusting further. (anything to apply)

i vaguely remember something by turtle, apply it onto rust and that spot would never rust further again. i cant remember the name of it.. (converts the Fe in rust) maybe somebody might know.

 

[theokalat]

my yamahas transformer has rust on it too.. i too would like to know how to treat it to prevent it from trusting further. (anything to apply)

i vaguely remember something by turtle, apply it onto rust and that spot would never rust further again. i cant remember the name of it.. (converts the Fe in rust) maybe somebody might know.

Yeah, its called rust convertor, but after some research on google, it is not recommended for metal that heats up like a amplifier transformer, as after a certain temperature is reached, this rust convertor releases very toxic fumes which can be carcinogous, and your amp being permanently located indoors, this is not a good idea to use this stuff.

I have found some stuff at RS Components called "Insulating Varnish". It is specifically designed for protecting transformers, wound components, PCB's etc. Rated up to +120 degrees C. This comes in a liquid bottle.

Another at RS is called "Printed Circuit Laquer". Rated over 150 deg C. and no need to remove before soldering if applied to PCB board. Can be used on transformers casing. This comes in a spray.

There are several other sprays, liquids at RS Comps that can also be used for this purpose.

Hope this helps others who were seeking for a solution like me.

 

[jimbofish]

Yeah, its called rust convertor, but after some research on google, it is not recommended for metal that heats up like a amplifier transformer, as after a certain temperature is reached, this rust convertor releases very toxic fumes which can be carcinogous, and your amp being permanently located indoors, this is not a good idea to use this stuff.

Can you tell me where you found this? I'd like to know more.

 

[asmd]

Can you tell me where you found this? I'd like to know more.

Rust Reformer: http://www.amazon.com/Rust-Oleum-7830730-8-Ounce-Rust-Reformer/dp/B000BZZ56S

 

[jimbofish]

I don't see anything there about the heating hazard. Guess I wasn't clear.