Concerned about possible corrosion on bottom of Falcon MB - Questions

[bripilot]

These are photos of the bottom of my Falcon 030 motherboard. The machine works and boots with no issues, however when I opened it up to clean up some wiring and install a GoTek, I decided to pull the board up from the shielding. On the bottom, I see several surface-mount caps and resistors with this corrosion around them. Probably 20-30 of them.

There has been no water or humidity exposure at least in the past 5 years or so that I've owned it. The cardboard barrier underneath the board is completely clean with no evidence of water spillage or corrosion.

Any ideas what could have caused this? Should I just clean them off with alcohol and reassemble the machine?

This is kind of like a car where it runs fine until you find out there's something wrong, and now you don't even want to turn it on.

I don't want to cause any further damage.

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[exxos]

Difficult to tell exactly but some of them do not look like they have been machine soldered. So maybe it is flux residue from manual soldering?

Indeed, gently wiping it with some IPA and see what happens.

[Steve]

I have seen this kind of thing on some Clab Falcons, I think around the PAL/NTSC circuitry area. I think Atari sold the motherboards to Clab without those components soldered, and Clab hand-fitted those parts. When I've seen this the soldering is obviously hand-soldered and not done by machine process... is yours a stock Falcon?

[bripilot]

Other than a few mods, like clock mod and Compact Flash for the HD, yes, it's stock vs. a CLAB.

I'm going to clean it this morning with some IPA and see how it looks afterwards.

Thanks for the quick responses!

[rubber_jonnie]

As well as cleaning with IPA, you could consider some clear lacquer over the affected items, as it might reoccur.

I usually do this on corroded board repairs to be sure that oxygen can't get through to these areas and start it off again. I use either clear nail varnish or solder mask.

Entirely up to you but I thought I'd mention it.

[bripilot]

You guys are geniuses!!! After cleaning with IPA, it looks great now. I went ahead and did the rest of the bottom of the board and then cleaned the top of the board as well. Thank you again!

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[exxos]