exxos's Atari, Amiga & retro forum

Slowly been getting on top of a lot of my projects and aside from the stubborn C128 & Mega ST I’m nearly up to date with everything retro :shock:

So after reading through the corrosion damaged computer threads I felt inspired to give it a try myself as well. So to make it interesting I got myself a cheap but battery damaged Mac LC-II. Externally it’s in nice condition, not so good inside.


The rom sockets, SCSI port and a few other bits need to be removed and replaced, so I started on them first.


Yes, looking under them I’d better remove a few more bits whilst I’m at it then.


Oh and did I say just about every electrolytic capacitor has a leak? So they have to go too.

Every one of those elctrolytics WILL have leaked and be eating the board. The battery damage doesn't look too bad though.

That looks to me like liquid damage.

Good luck, I guess. :)

stephen_usher wrote: 18 Oct 2023 19:15 Every one of those elctrolytics WILL have leaked and be eating the board. The battery damage doesn't look too bad though.

They are definitely being binned but I’ve got to work out what I need first.

@mrbombermillzy it was liquid, battery acid and electrolyte.

I have to say, I think you dodged a bullet (At least I hope you did) because the corrosion looks like it could have been way worse.

Lot's of white vinegar required and a good clean after, fingers crossed there isn't much trace damage.

I especially hate batteries in old Macs!!!

It's also reminded me that I should never have got rid of my LC475, it was a cool machine compared to the bog standard LCs I had, which I managed to recover from a school that had a big pile of them in the basement, including keyboards and mice.

Wish I'd kept one of the extended ABD keyboards too. Damn it!!!

LC475 motherboards are well sort after as they're one of the fastest m68k Macs. The 040 flies in them, faster than the early PowerPC designs (which were slow).

@rubber_jonnie some of the vias look decidedly dodgy but so far I can’t see anything too bad, a few areas where the solder mask has lifted but hoping the tracks haven’t.

Anyway, it’s a bit of fun, if I’m the end it doesn’t work then I’ve learned some of the tricks to repairing corrosion.

Incidentally the battery holder came off quite easily, something to do with acid eating it away :lol:

PhilC wrote: 18 Oct 2023 20:10 Incidentally the battery holder came off quite easily, something to do with acid eating it away :lol:

They do tend to do that. ;-)

PhilC wrote: 18 Oct 2023 20:10 @rubber_jonnie some of the vias look decidedly dodgy but so far I can’t see anything too bad, a few areas where the solder mask has lifted but hoping the tracks haven’t.

Anyway, it’s a bit of fun, if I’m the end it doesn’t work then I’ve learned some of the tricks to repairing corrosion.

Incidentally the battery holder came off quite easily, something to do with acid eating it away :lol:

I'm very much looking forward to your posts about it :)

The Maxell bombs do make a bloody mess when they go off, so I'm not surprised the cell holder dropped off.

So I’ve replaced the dodgy corroded rom sockets and SCSI port. Opened up and checked the PSU for exploded caps and found none, just a bit of external corrosion.

I’ve not replaced the leaking caps yet but will do ASAP but wanted to see if it actually booted at all before I did anything further.

So it looks a little like this, let’s see if I can get it powered up later on.