Macintosh Iici build questions/MMU

T-Man

Tinkerer
Oct 30, 2021
74
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
74
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
30
22
8
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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T-Man

Tinkerer
Oct 30, 2021
74
40
18
Tennessee USA
Bummer….not finding the part number on another board to replace UK11 MDU on the IIci board…. maybe file some edges and microsurgery someday