68kMLA Classic Interface

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My Battery Bombed IIci needs some new parts
Posted by: AlexADB on 2023-12-30 23:46:52
Hi all, I just got a Mac IIci that was battery bombed. I cleaned up the motherboard and found out - next to the corrosion and salts here and there, it looks not too bad.

  1. I think the rom is damaged, so I ordered a ROMinator II as a replacement
  2. The oscillator on Y6 fell off and was super rusty.. @GRudolf94 helped me in the other thread to find the values 👍
  3. The diodes D7 and D8 are damaged and D7 fell off already. I found something looking like the one which fell off .. (https://www.reichelt.de/ldo-regler-...3480-im3-5-0-p187727.html?&trstct=pos_9&nbc=1) but I do not know the values, maybe one of you knows?
Please find a photo of the bad battery here 😱

The machine powers on without the battery, and without the oscillator / diodes / potential rom damage. Even the screen lights up, but stays purple / grey. I assume, without the oscillator there is no way forward. The diode might not be needed, I guess. Is it needed at all? Especially when I plan to put in a CR3032...

Thank you already in advance for any support and best greetings from Bavaria
Posted by: GRudolf94 on 2023-12-30 23:54:51
D7 and D8 are both 1N914, but almost anything will do - you need to replace D7, else the RTC will drain the battery even while the machine is on.
It's interesting you get anything on the video. But yes, you absolutely need Y6 in place - MDU (the main controller chip) is clocked off that, and feeds the CPU 25MHz by dividing it down by 2.

Best of luck!
Posted by: AlexADB on 2023-12-31 08:36:09
Thank you so much! I installed the new oscillator today. But the system behaves the same still. Waiting for the ROMinator…
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