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128k vs Rust
Posted by: Durosity on 2022-08-23 03:36:49 So picked up a wee 128k Mac for cheap the other day. I could tell from the photos that it was clearly rusty and I didn’t really expect it to be usable, but I wanted it anyway so bought it. Just got it delivered and cracked it open.. I’ve never seen so much rust before.. it’s so bad the brackets that hold the logic board in place have rusted onto it. That said the damage to the logic board doesn’t look awful.. I’ve not yet been able to see it in full (I think I’ll need to dremmel the frame off) and there only seems to be superficial rust on the analogue board. This could be an interesting restoration…
Posted by: bibilit on 2022-08-23 03:44:23 flooded ? haven't seen so much rust except for Maxell bomb boards.
Posted by: Durosity on 2022-08-23 03:50:26 Possibly. Or sitting in a damp shed perhaps? It’s certainly not as bad as my twin Maxell bombed IIfx board!
Posted by: bibilit on 2022-08-23 03:55:49 I think I’ll need to dremmel the frame off twisting it should help
Posted by: Durosity on 2022-08-23 04:07:54 Yeah I’ve tried but no joy, but I’ll give it another go before I go to extremes.. although that said I suspect the frame is beyond saving so I’d rather rescue the logic board in as best shape as possible if it comes down to it
Posted by: cheesestraws on 2022-08-23 04:28:54 Well, that's certainly a project waiting to happen. What on earth happened to that?! :-D
Posted by: joshc on 2022-08-23 04:29:16 That looks terrible. I wouldn't hold out hope for that one. Looks like water damage. The rust will most likely have damaged the traces unless it is literally only sitting on top of the surface. Hope you didn't pay too much.
Posted by: Durosity on 2022-08-23 04:48:47 That looks terrible. I wouldn't hold out hope for that one. Looks like water damage. The rust will most likely have damaged the traces unless it is literally only sitting on top of the surface. Hope you didn't pay too much. Well until I can free the motherboard it’s hard to say what the damage is. That said I can do a fair amount of board repairs.. it’s just a question of if it’s worth the time and energy.. but every 128 that can be recovered is probably worth it!
Posted by: LaPorta on 2022-08-23 07:03:24 If you just straight out replace the frame and logic board, it could work. Yeah, that definitely just sat in water. Nothing else would cause that except immersion.
Posted by: 3lectr1cPPC on 2022-08-23 07:12:34 That is well and truly a mess. Good luck getting it running again!
Posted by: Durosity on 2022-08-23 12:57:03 Well the logic board doesn’t look awful but does have some damage. What’s your thoughts on restoration.. plausible? I’m pretty good with recapping and minor trace repair but I’m guessing this will take a fair bit more than that. Interestingly it seems to be an original version pre 512k, which I didn’t think shipped outside of the us (I’m UK based and this is a 220v P model)
Posted by: Pushpull76 on 2022-08-24 01:38:21 Ouch save this poor boy, please.
Posted by: Phipli on 2022-08-24 01:44:29 Well the logic board doesn’t look awful but does have some damage. What’s your thoughts on restoration.. plausible? I’m pretty good with recapping and minor trace repair but I’m guessing this will take a fair bit more than that. Interestingly it seems to be an original version pre 512k, which I didn’t think shipped outside of the us (I’m UK based and this is a 220v P model) View attachment 45499 Given they're not that common over here I'd just make a start on it - you never know, perhaps everything will just fall into place. Where abouts are you? If you're midlands based you're welcome to give it a swim in my ultrasonic. It was a good start with this corrosion damaged 475. Edit - ah, I can see from your profile that you're Up North 🙂 Well, if you're passing through the offer stands.
Posted by: cheesestraws on 2022-08-24 02:04:06 What does the bottom of the board look like? It'll be a project to get it working again, but it might be possible. And it will be satisfying if you do.
Posted by: bibilit on 2022-08-24 02:10:15 Probably a good start will be cleaning the board will some white vinegar do get rid of a fair amount of rust and dirt. Yes first issue of the 128k, the second batch were given the marking 128 / 512
Posted by: Phipli on 2022-08-24 02:16:59 Probably a good start will be cleaning the board will some white vinegar do get rid of a fair amount of rust and dirt. Yes first issue of the 128k, the second batch were given the marking 128 / 512 You normally use vinegar to neutralise the alkalinity from a battery. I'd hold off using an acid on water damage as acid promotes corrosion. I'd start with electronics cleaning fluid which has some soapy stuff in it, or a mild solvent like IPA, but suspect IPA won't make inroads into this based on my experience with the water damaged 475 last week.
Posted by: Pushpull76 on 2022-08-24 02:18:27 ASG chip is marked 8423? @LaPorta 🥲
Posted by: Durosity on 2022-08-24 02:20:03 Where abouts are you? If you're midlands based you're welcome to give it a swim in my ultrasonic. It was a good start with this corrosion damaged 475. Edit - ah, I can see from your profile that you're Up North 🙂 Well, if you're passing through the offer stands I appreciate the offer! I do need to get an ultrasonic at some point, or possibly make my own. I do have a rather large pile of machines which really do need a full restoration.. I’ve been slowly converting my garage to be suitable for all this work.. but I’ve rather overspent lately! What does the bottom of the board look like? Pics at the top of the thread. It’s stained, but doesn’t seem horrific. My worry with this repair is going to be having something to cross reference it with, but I do have a 512k Mac which is fully working, so I’m hoping that will be close enough.
Posted by: cheesestraws on 2022-08-24 02:31:33 Pics at the top of the thread. It’s stained, but doesn’t seem horrific. ... I'm paying attention, honest. Not sure how I missed that. My worry with this repair is going to be having something to cross reference it with, but I do have a 512k Mac which is fully working The attached may be of use to you. I think this is for the original 128k. I also may have a spare international AB if you need one for 'repairing one thing at a time', Well, I do have a spare but I'm not sure if it works 🙂 would have to check. edit: now with attachment
Posted by: Durosity on 2022-08-24 02:36:33 ASG chip is marked 8423? @LaPorta 🥲 What’s the significance of this? 🤔 I also may have a spare international AB if you need one for 'repairing one thing at a time', Well, I do have a spare but I'm not sure if it works 🙂 would have to check How much would you want for it if you do? I actually have a couple of machines that I can use for that purpose, but I’d actually like another one for a Mac plus that’s missing its one! and thanks for the schematic, that will be most helpful!
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