When I upgraded my 3000 from 8 to 12 Megs I noticed many weird memory related problems. Lots of RAM tests and some research later I took out the board to find a socket with 2 address lines completely unsoldered...
I would check continuity from the SIMM socket to Alice (through U212) - probably one of the RAS/CAS lines is faulty. Are the 8/2 MB chip jumpers in the 2 MB position?
