corrosion

[rrch123]

I have some corrosion that I need to get rid of. Can anyone tell me what would be the best kind of chemical to use to get it off?
Thanks

 

[Electronics4you]

Just use some WD40, let et dry for 24 hours adn then you can remove the corrosion with a wire brush.

 

[HiTech]

It depends on what kind of corrosion you are talking about. Can you tell us more in detail? Is it battery acid corrosion? Is it rust? Is it oxidation? WD40 can be like water to some chemical corrosions. A mixture of boric acid and water (tablespoon of BA to a cup of warm water) will quickly eliminate battery acid corrosion, followed up with a good wire brushing. Rust can be removed with PB Blaster or Naval Jelly, again followed up with a wire brushing. Muratic Acid will dissolve other corrosions but it's rough on plastics and your skin, so be careful. Any removal of corrosion to terminals or foil traces should be finished by following up with a solution of ElectroWash or similar non-residue electronics cleaning agent. I like to use a Dremel Moto tool with a wire brush tip to burnish the traces or contacts. It restores operation back to new. My final step in the whole process is to coat the repaired surface with a quality contact cleaner such as CRC or DeOx-it or similar.... not WD40. Leave that can for use in the wood or metal shop. It doesn't belong on the electronics bench other than to lube a squeaky chair or door hinge!

 

[rrch123]

I guess I should have told more. I was writing my last post when I was ready to crash in bed. I am taking under a project that is probably way over my head. Some water got into my cellphone and the corosion is in the phones hinge, as well as on the circuit board that controlls the screen.
As far as what kind of corrosion, I am not sure. It looks kind of like Elemers glue from grade school. I compaired that section of the phone with pictures on the internet to make sure that it really was not glue, and non had that stuff. I can only say that it has to be the corrosion. Since I am dealing with a phone here, the space is real small, and some of the corrosion is hidden behind the top screen. From what I can see, the corrosion is on the contacts for the connector that connects the rest of the phone to the screens board. It is also all over some what looks like either resistors or capacitors. Who knows what else behind the screen.

I have tried using achocol and WD-40 the other day, and the achocol did not work, and the WD-40 did a really good job of cleaning the water stains on the metal cover, but did nothing for the contacts or anything else.

 

[Nigel Goodwin]

Buy a new phone! - water and electronics (particularly complicating tiny electronics) don't mix!.

 

[HiTech]

Ok that's an easy fix if you have the patience and determination. My daughter's mp3 player had the same thing happen to it. The residue you see is likely to be mineral deposits like that of lime or calcium. Use a stiff toothbrush to remove most of it. Next use rubbing alcohol along with the toothbrush (just don't put it back in your bathroom vanity) to continue to remove the mineral residue. Once everything is cleaned, use a non-residue circuit board wash like that in a spray can. wipe everything clean and dry and then test the phone. If nothing else you'd still need to buy a new one but at least you tried to fix it.

 

[rrch123]

did not work

Well I spent about 4 hours and got off all the corrosion, but to no avail. About four weeks ago, I sent to the phone to the techs at a radioshack store that was suppost to be able to handle motorolas. The phone was turning on, it was just flashing and saying that it would not accept the sim card. When I sent it, I made sure that the battery was out. I wait for about three weeks, then they call and say that they cannot repair it. When I get it back, the battery was in it and it would no longer turn on. I wish that I would have just tried this ealier myself. My point is that is there anything else that I can do to try to bring it back?

Thanks

 

[HiTech]

corrosion can be a strange bedfellow. You can remove it visibly but it could have taken its toll on foil traces or even under components that you cannot access. That me be the case with such tiny and compact circuitry as a cell phone. You'd need a magnifying headgear to see if all corrosion is truly gone... and even then the circuit could be ruined from all sorts of erroneous conducting paths caused by corrosion. Looks as if you may need to buy a new one. If you do get it working you also run the risk of intermittent reliability.

 

[rrch123]

One last thing if anyone is still listening, what about the Ultrasonic Cleaners? Does anyone know if they are any good? Maybe one could get some corossion in the phone where I can't?

 

[Oznog]

You'd have to immerse it. Most ultrasonic cleaners are water-based which would kind of defeat the purpose!

BTW, neat trick- dollar stores and flea markets now sell a cheap-ass electric toothbrush. Same idea as the good ones- a round brush head that rotates a few degrees back and forth rapidly. I wouldn't use it for my actual toothbrush, but these things are GREAT for cleaning small objects!

 

[rrch123]

Forgive me if this seems like a stupid question. Would achocol work instead of water?
Also, I did not think about using a electric toothbrush. I might try cleaning off again.

 

[dknguyen]

It probably would for regular PCBs. But things like speakers, microphones (and possibly LCDs) cannot be immersed. ALcohol is also conductive so you want to let it dry out completley otherwise a short may occur when you turn it on.

 

[hjames]

I don't know the actual details for PCB production, but I'm pretty sure that most PCB's go through a (water based) wash cycle in order to get rid of flux and stuff after the boards are built. I think ultrasonic cleaning is pretty common too. Mind you the sensitive parts usually have either protective tabs/coverings on them to protect them - or are specified to be non-washable.

 

[rrch123]

I have pretty much all the sensitive parts taken out already. To be frank, this cellphone is pretty well usless as is anyway. The way I look at it is that I have nothing to lose.

 

[Sceadwian]

The main problem with cleaning chips like this is the pcb clearance of most surface mount chips is virtually non-existent, so they tend to trap any liquid's underneath the chip itself, even cleaning sollutions, and it makes getting any corrosion from underneath the chip itself virtually impossible. The small legs on the IC's are also so close together they tend to capture liquid via capilar action and depending on how hard you dig into the PCB and the parts on it they might not all be 'washable' rendering a dip ultrasonic cleaning atempt to just kill it worse. Corrosion or cleaner they all make decent conductors especially the oxides and residues that basically for capacitors on the leads. A device corroded that bad should just be recycled and replaced.

 

[CanonMan75]

A few years ago, I worked for the local mobile phone repair workshop.

Any phones that came in with even the smallest signs of liquid spillage on PCBs were sent back as BER straight away. Previous experience had shown that any kind of repair where liquid damage was involved could take ages and probably not be reliable, hence the BER policy.

The best example I ever encountered was a Samsung A800 (IIRC) which had water in the flip-up part - looking at the little round outer display window with a water line half way up reminded me of the view from a ship's windows

Well I spent about 4 hours and got off all the corrosion, but to no avail. About four weeks ago, I sent to the phone to the techs at a radioshack store that was suppost to be able to handle motorolas. The phone was turning on, it was just flashing and saying that it would not accept the sim card. When I sent it, I made sure that the battery was out. I wait for about three weeks, then they call and say that they cannot repair it. When I get it back, the battery was in it and it would no longer turn on. I wish that I would have just tried this ealier myself. My point is that is there anything else that I can do to try to bring it back?

Thanks

 

[HiTech]

Forgive me if this seems like a stupid question. Would achocol work instead of water?

Most alcohol leaves a residue which is what you don't want. You can tell by running several drops of it on a mirror or clean glass, allowing it to dry then observe the residue. Quality contact or board cleaner will not leave trace residues, hence why you pay more for the stuff.

 

[rrch123]

Where can I get these cleaners?

 

[Nigel Goodwin]

As I said way back in this thread, it's not something worth attempting, even if you did (by some miracle) get it working, it's not going to be reliable as it will continue to corrode where you can't clean (such as under SM components).