🚀 go-pugleaf

I have made progress on locating the problem, but still am in trouble. 
We have:

1) Tested my logic board, and a brand new 512 logic board, using MY 128K
ROMs, and no memory expansion board attached.  Result - perfect!  We could
not make either board fail. We ran for 90 minutes.
2) Tested the analog board - 4.85V with the additional memory board attached.
3) After warmup, the whole package fails after a few minutes when working
from the desktop - multiple applications, etc.  Most failures are ID 02
and 03.  A few 10, several 25.
4) I can run in Kermit for HOURS!  No failures.
5) I run the Macs-a-Million memory tests - all available tests - for upwards
of 5 DAYS! One error on bit 6 in the first 10 minutes, not a single failure
thereafter.
6) I tear my hair out (I don't have that much to spare).
7) Some programs tell me I am out of memory for a particular action.  Some
fail with error 25 (out of memory).  All programs with messages (Finder,
MacDraft, etc.) tell me I have 2048K, so it is apparently available.

I need two things from you Mac heavies:
	a) Suggestions on how to proceed at this point.
	2) Leads to some hardware heavies in the Boston (west) area to bring my
	box to for pursuit and repair of the problem.

My car blew a head gasket, and the towing company put body damage on it
taking it to the shop.  I can handle that.  My Mac has been flaky/down for
nearly two weeks.  I can't handle that...  HELP.

Thanks in advance.
Gary