ajricker

I pulled the control last night with the intention of resoldering it. The box appeared to have not been opened before.
When I pulled the board to do the resolder it appears to have been dipped in a lacquer.
Will this pose a problem for resoldering?
I've repaired a few motherboards in the past. So I do have some experience at this.

Adk46

I have no experience at repairing boards, but i know some metallurgy that may be useful.

There will be two sources of solder or trace failure. One is corrosion - between the lacquer and visual inspection, I'd expect that it would be obvious if it's occurred. The other is "thermal fatigue", metal fatigue caused by the material getting pushed and pulled by temperature differences and/or differences in thermal expansion of materials joined together. This will result in cracks that may not be so obvious. The worst thermal strains will be caused by connections that get hot, that carry a lot of current for their size (or had lousy joints to start with).

So, I'd search for discoloration, paying attention to the "power" circuits. I'd use a jewelers loupe. I suppose nail polish remover would remove the lacquer, either to allow closer inspection or before resoldering.

(My closest colleague in grad school - we both studied fatigue - went to IBM and worked on thermal fatigue issues in integrated circuit connections.)

Other than solder, the most unreliable components are electrolytic capacitors, so give them some scrutiny, too.

I hope you get advice from someone with experience. I should be getting some eventually, since my CC doesn't work.

ajricker

Thanks Adk46,
On fist inspection I didn't see any discoloration or apparent component failures. I'll take a closer look.
Hopefully someone that's btdt will chime in.

SMTCapeCod

I opted for the $80 ebay rework service.
That's about all cc is worth to me, I don't use it, except to see whether it's working.

So far, working well, full function restored.

ajricker

To me it's only worth my time. If I can fix it myself great if not oh well. :-p

Chris

I seem to remember I used something to get rid of the conformal coating, might have been paint stripper for a short period of time. If you and try and solder without removing the coating you are just gong to contaminate the solder.

I examined mine pretty closely and could not see an issue and re-soldered and it worked fine, like you said it is just your time

PCARUSA

Yes the board is dipped in conformal coating for protection. I would remove the coating wherever you want to re-solder. I use a fiberglass 'paint touch up' pen for the small areas. Not sure what I would use to remove conformal coating for large areas. There are two electrolytic capacitors 47uF that you might want to replace. I have some new spares you can have if you want them.

Bmw635

The coating is conformal coating. Search for info on removal prior to soldering.

ajricker

Thanks guys, sounds good.