Macintosh Iici build questions/MMU

T-Man

Tinkerer
Oct 30, 2021
73
40
18
Tennessee USA
I have a battery bombed Iici with several legs of the MMU (and multiple traces) eaten away. Aside for the MMU, the other chips look salvageable. I have a Bolle Iici new board and some parts for it and had planned to use a IIsi board to salvage chips /IC's as a backup. However, now looking closer and before starting a lot of work, I'm not so sure about the MMU. The text on the MMU from battery bombed CI is barely visible but is consistent with this picture of a CI MMU I enlarged from "Recap-A-Mac". The IIsi MMU is a picture of the board I actually have. Can I use the MMU from the IIsi board to replace the damaged one on the Iici board?
ActualCIMMU.jpeg
AcualIIsiMMU.jpeg
IICIMMUonline.jpeg
 

T-Man

Tinkerer
Oct 30, 2021
73
40
18
Tennessee USA
So it’s looking like the MMU on IIsi and IIci are the same chip. The build will be a while but will give it a shot. Thank you for posting. Will go look again, on looking at the traces leaving the chip, there seems to be diffeneces.
 
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DevyDevly

New Tinkerer
Nov 17, 2024
29
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3
New Zealand
I was re-reading this and might have made a mistake - apologies.
The MDU (UK11) on my IIci machines is either a 343S1059-A, 343S1059-B, or 343S1018-A.
It was the RBV (UE9) that is the 343S1019-A.
i.e. I don't think you replace a IIci MDU (UK11) chip with a 343S1019.

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