Lunar Lander pcb restore

[mantisgamer]

I'm attempting to restore this pcb or at minimum improve its cosmetic condition somewhat. To do so I need to know what type of metal is covering the section in the picture. It appears to be a plating over copper but I'd like to confirm. Any help is greatly appreciated!

 

[andrewb]

It's tin over copper.

What do you plan to do to it? (And what happened to it?)

 

[mantisgamer]

Not sure what happened to it or what is causing the discoloration. I suspect it is moisture that caused this but I was thinking of replating. I know you have more experience with this sort of thing. Any suggestions?

 

[andrewb]

I don't think you're going to make it look a lot better. I'd just get it working. You need a 561 DAC, I'd replace all 4 pots (including the missing one), and clean that edge connector with a fiberglass pen, then hit it with some DeOxit. Then test and see where you're at. You're probably going to have other bad parts, as that's common on these.

Everything else looks cosmetic. You could replace those electrolytic caps, but they're probably still fine. I try to keep things original unless they test bad and truly need to be replaced.

 

[ArcadeTechGW]

You don't need to replate this, and trying to will be a waste of effort. The tin is there to stop the copper from oxidizing and corroding in moist air.

Start with the component which seems to be ripped off in the middle of the area.



Some of the capacitors in that area look bad, but that doesn't mean they are. Do you have a working Atari power brick and AR board so you can test this out?

Do you have a LL manual so you can determine what the missing part(s) are?

 

[cwilkson]

The edges are pretty badly corroded and delaminated. To replate that, you'll have to remove all the components, then remove the existing plating without disturbing the underlying copper. Then do a proper re-plate.

If your day job isn't chemical-metal plating then don't attempt it. And if you do it every day, you're still very likely to ruin the board. The effort involved to achieve any level of improvement is deceptive.

Just don't do it.

The best thing you can do safely is to get a 3/8" hoghair bristle brush and cut the bristles to 1/4". Add salt and baking soda to water and scrub the worst parts with that. Even this will be destructive because it's going to remove some of the egde material that's already flaking.

I agree with @andrewb and @ArcadeTechGW. That damage is just cosmetic. Ignore it and repair/replace the circuitely in a functional sense.

 

[mantisgamer]

All great advice. Thanks!

 

[joeycuda]

I have a BZ aux board that is about as bad. I figure moisture exposure in storage. I don't know that the plating can be polished in any way. It's at about the bottom of my priority list.