I still wanted to fix my Macintosh, but didn’t know how.  It sat on the back burner of my mind, but one day I stumbled across an article that said the Sad Mac error 0F0003, although defined as an instruction error, sometimes meant there was a problem with the memory.

I looked on ebay and found a matched set of 4-1MB simms.  I bought them fairly cheaply (read that under $20) and several days later they came in.

I opened the case, pulled out the old memory and replaced it with the new set of matched simms and closed up the case.  When I booted up the Macintosh it worked.  I left it running overnight, using it occasionally and had no problems with it.

Last Update: 28-Aug-15