Yet another battery bombed Colour Classic

[akaitea]

I'm fairly new to collecting retro computing, mostly concentrating on retro PC gear but I do grab anything Macintosh if it comes along which is an extremely rare occurrence in my country. A seller put up a non-working Macintosh Colour Classic on a local auction site with a starting price of 170eur, it didn't sell. It was clear from the photos that something had leaked out of the case, I thought it was the caps initially and contacted the seller stating this and offering him 60eur, after he took out the logic board and sent me photos of the disaster, he countered with 70eur and here I am wondering if I am sane to buy something knowing full well it is broken and probably unfixable...

So I'm sharing my pain with everyone, for history's sake...

The case...




The logic board...





On top of that of course the caps have leaked...





The analog board looks fine except for one leakage located right around the centre of it...



I'm not holding much hope as I don't have the skills to attempt to fix this on my own, most I could maybe get by doing is changing the caps, and poorly. Would probably make more sense to get another logic board but they are expensive and unavailable locally, ordering from abroad is even more expensive thanks to customs charges.

For now I'm going to start with giving the logic board a bath and scrub using the usual formula: white vinegar (I actually have some ethanol based 9% vinegar hope thats fine) -> baking soda -> distilled water -> 95%+ IPA in order to assess the damage and then go from there...

 

[bibilit]

not much to lose, but hopes are thin...

 

[ironborn65]

So sad, but it worth trying to salvage it

 

[chiptripper]

It’s a good purchase, you can fix that up. I have some CC spare parts I could sell you… I have two of those metal RF shields, a few analog boards (need caps and a few parts) and at least one CC logic board (I think it’s even recapped.)

I’m in Canada though so could be expensive to ship and import.

 

[imactheknife]

It’s a good purchase, you can fix that up. I have some CC spare parts I could sell you… I have two of those metal RF shields, a few analog boards (need caps and a few parts) and at least one CC logic board (I think it’s even recapped.)

I’m in Canada though so could be expensive to ship and import.

You have an analog board? I would also be interested.

 

[akaitea]

Well I cleaned it up as best as I could without getting into de-soldering components in order to asses the damage and what to do next...



It actually cleaned up better than I thought it would...



The majority of the damage is on this LS245 chip which is apparently a TI Octal Bus Transceiver and should be possible to acquire






The 2 affected AM26LS chips near the ports in the back look ok but probably need to de-solder them to assess them properly and to clean up underneath, along with de-soldering the ports and giving them a proper cleaning, probably best to just replace them completely if they can be acquired. These ports are for printer and modem which I don't even need but I doubt the board can run with missing components.



All in all I'm in way over my head, I'm going to take the board to a local motherboard service place that does all kinds of motherboard and GPU work, they are quite good apparently so I'll consult them and see if they or someone they know can do the work on this board, and if its even financially feasible or if I should forget about it and try and get a working board.

to be continued...

 

[3lectr1cPPC]

many of those vias are probably rotten and will need patching. possible damage to the inner layers of the board too, all you can do is test continuity and see. best of luck!

 

[Cam]

You should find a replacement for the metal shield that has rotted away as Apple used that to tie the ground points on the LB together. Also the missing GC3 leg will need to be replaced as it's one of the ground points the shield connects. Otherwise you'll need to wire all the GCx points together.

I've got a set of SIMM sockets if yours didn't clean up well.

 

[jshardin]

Well I cleaned it up as best as I could without getting into de-soldering components in order to asses the damage and what to do next...

View attachment 51363

It actually cleaned up better than I thought it would...

View attachment 51364

The majority of the damage is on this LS245 chip which is apparently a TI Octal Bus Transceiver and should be possible to acquire

View attachment 51365


View attachment 51366

The 2 affected AM26LS chips near the ports in the back look ok but probably need to de-solder them to assess them properly and to clean up underneath, along with de-soldering the ports and giving them a proper cleaning, probably best to just replace them completely if they can be acquired. These ports are for printer and modem which I don't even need but I doubt the board can run with missing components.

View attachment 51367

All in all I'm in way over my head, I'm going to take the board to a local motherboard service place that does all kinds of motherboard and GPU work, they are quite good apparently so I'll consult them and see if they or someone they know can do the work on this board, and if its even financially feasible or if I should forget about it and try and get a working board.

to be continued...

The issue isn't going to be finding replacement parts... It's going to be any vias that have been destroyed connecting all of the layers. I can already see a number of vias that look to be in pretty poor shape. No repair shop worth their salt would say this would be financially feasible; there is at least 10hrs of work just removing everything corroded here and checking the vias. It literally would take just a single rotten via with no access in between the layers to make this board unrecoverable. That's not to say there isn't anything of value left on the board, but trust me, taken from someone who went down this rabbit hole before, go find a replacement board and save yourself a ton of money and heartache.

 

[pizzigri]

I'm waiting for a Color Classic to be delivered, and it's supposed to be a pristine machine, purchased to be used for the last year of University by a girl and once she graduated, left alone in a box for 25+ years. Photos looked terrific online, but the lady said it does not boot up... I'm crazy anxious to see what will actually arrive. Reading this and other posts is making me really depressed

 

[Durosity]

I'm waiting for a Color Classic to be delivered, and it's supposed to be a pristine machine, purchased to be used for the last year of University by a girl and once she graduated, left alone in a box for 25+ years. Photos looked terrific online, but the lady said it does not boot up... I'm crazy anxious to see what will actually arrive. Reading this and other posts is making me really depressed

You may get lucky, i recently picked up a CC in a similar situation and the Maxell battery hadn’t grenaded it!

 

[chiptripper]

A lot of CCs avoid this fate simply because the logic board is so easy to remove, so battery gets pulled or replaced.

 

[chiptripper]

The issue isn't going to be finding replacement parts... It's going to be any vias that have been destroyed connecting all of the layers. I can already see a number of vias that look to be in pretty poor shape. No repair shop worth their salt would say this would be financially feasible; there is at least 10hrs of work just removing everything corroded here and checking the vias. It literally would take just a single rotten via with no access in between the layers to make this board unrecoverable. That's not to say there isn't anything of value left on the board, but trust me, taken from someone who went down this rabbit hole before, go find a replacement board and save yourself a ton of money and heartache.

Yes agreed, after the cleanup I am revising my former optimism. This is a parts board, you are better to just replace the LB and shield.

 

[imactheknife]

I have a couple of recapped cc logic boards if interested.

 

[akaitea]

Just want to provide an update for the curious. a whole 2 years later I have finally acquired a board for an acceptable price (€54 + shipping from Japan). It came loaded with RAM and a co-processor too so I think I lucked out. It came with a battery (yikes) but more on that later....




The caps have leaked but doesn't look like they caused damage, board will need a thorough cleaning and recap :







I would also like to thank this German battery for not exploding for 32 years:



Lots of work still left, need to clean and recap this board and most likely the analog board too but hopefully one day soon it will be brought back to life

 

[Callan]

Congrats! That board looks great! Some new caps and a clean and you should be good to go. A far cry from your original battery bombed one!!! If you haven't found a replacement cage for your cc I'd make sure to sand down your old one and prime it. I had a classic that had a battery bombed board in it and had to the same. The board was toast (replaced it with a classic ii), but with a little sanding and wire brush (that battery acid rust is stubborn) you can save them. Just prime with a grey primer and it looks close to original. Good luck with your project!

 

[akaitea]

Thanks for the info, I was wondering what to do about that as I don’t anticipate I'll find a new cage, seems I'll have to connect the grounding points on the board to the cage too somehow

 

[bibilit]

Egret will have to be cleaned or removed for cleaning underneath.

 

[adespoton]

Thanks for the info, I was wondering what to do about that as I don’t anticipate I'll find a new cage, seems I'll have to connect the grounding points on the board to the cage too somehow

If using fine grit emery cloth doesn't do the trick, you can always solder alligator clips onto the cage and clip them to the contact points on the board. I've never had to do that on the CC though; sanding has always been enough, along with bending the tabs slightly to increase pressure.

 

[akaitea]

Some more stuff arrived, now it is complete with mousepad and everything. Just to get caps and repairs done and I can try and fire it up