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IIsi fault ...


Active member
... nevertheless trouble with the RAM, more precisely with the ALS245 chips.

UF5 Pin18 (D8) has no contact with the Simm socket pin3
UG5 Pin13 (D21) has no contact with the SIMM socket pin20

Unfortunately the VIA from D8 was under the ALS245 and had to put a wire around the board. On D21 I was able to patch the spot with solder.

The Macintosh IIsi board doesn't seem to be of such good quality!?! The schematics are terrible too ...

I'm glad it's working again


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Well-known member
the macintosh IIsi was a cheaper, low cost alternative to the IIci... so its a bit haphazard in terms of internal design. it's an okay machine and it works for what it is.