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Salvaging a bombed SE/30
Posted by: ironborn65 on 2024-09-30 10:18:00
Hi guys,

For a decent price I found a bombed SE/30 that can hopefully be salvaged. A reloaded board is the B plan.

As I got it:

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after a round in the dishwasher and some scrubbing with vinegar:
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I need to keep scrubbing and rubbing, more washing and rinsing ...
At this moment it does not seem so desperate. Nevertheless, Y1, D1, D2, RTC, 2 or 3 of RAM mux are gone. About the traces ... to check later.
The RTC is a custom chip (https://www.quantulum.co.uk/blog/new-timepiece-for-a-classic-mac-part-1/), I hope I can get one, but it could work without D1 D2 Y1 and RTC, I'll miss the timekeeper, is it? The RTC can be tricky to find.

For the RAM mux, I found the replacement in Bolle's BOM for the SE/30 reloaded (https://docs.google.com/spreadsheets/d/1CAzGjHxQaQrduQC-hQ8sB2I6Y56fUlCWdJMCUDho0NE/edit?gid=0#gid=0).

It's not my first recovery of a Mac motherboard, so I'm comfortable with recaps and SMD soldering but it's my first bombed Mac.
How would you proceed? Ideas, or suggestions besides the usual thorough cleaning, batch, IPA, continuity?
I could take the opportunity to replace the SIM/ROM sockets...
Posted by: joshc on 2024-09-30 13:32:19
A vinegar soak may help remove some of the corrosion. IPA itself isn't great at removing this type of corrosion.

Use a scapal blade to scrape off corrosion from traces, revealing the copper underneath the solder mask.

Use hot air to remove the muxes.

Use lots of flux and solder wick to help remove the corrosion and dirt, it should all get soaked up by the wick.

You may end up having to replace that ROM socket, I can see some light corrosion on it and the original sockets are crappy anyway.

Good luck, this one looks like it could be saved, although bear in mind... corrosion inside the inner layers/vias might be a problem you can't escape.
Posted by: croissantking on 2024-09-30 16:56:01
The RTC is a custom chip (https://www.quantulum.co.uk/blog/new-timepiece-for-a-classic-mac-part-1/), I hope I can get one, but it could work without D1 D2 Y1 and RTC, I'll miss the timekeeper, is it? The RTC can be tricky to find.

I think you can find original RTCs in AliExpress, otherwise making an ATTiny85 replacement chip is an option. I've assembled a few and could sell you one if you'd like.
Posted by: Fred1212 on 2024-09-30 17:13:55
Looking at your board I think it suits a reloaded. You have the possibility of spending a lot of time testing and track repairing compared to a parts swap. Mind you you may be lucky and its easy to fix but!
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