13 May
2014
13 May
'14
5:02 p.m.
Sorry Dave, it might be my mail client, but I can't seem to figure out how
to quote posts on this system.
So.. does your 1MB "128K" have a set of SIMM slots with SIMMs plugged-in?
That would be a Plus board, if memory serves.
IIRC, the 128K and 512K models had everything soldered (no SIMMs, no
sockets) directly to the motherboard. And as such, an upgrade would require
some very dicey solder re-work to replace the chips, or some sort of
piggyback arrangement, which I've seen on other 80s era machines - and
video game consoles.
On Tue, May 13, 2014 at 6:21 PM, David Riley <fraveydank at gmail.com> wrote:
On May 13, 2014, at 18:55, "drlegendre ."
<drlegendre at gmail.com> wrote:
Back at the time, it was apparently common for folks to replace the ROMs
in
a M0001 128K Mac with the ROMs from a 512 /
FatMac. Some other enthusiast
might have snagged them for their own upgrade project.
Among other things, the swap allows the 128K machine to boot directly
from
an external HD, like the SD20. It may have other
changes and hooks, to
allow use of later MacOS versions - but on a 128K board, I'm not sure how
far that gets you.
Well, upgrading a 128k board to 512k is a relatively simple
operation, since they were the same actual board with a
different BOM. Getting beyond that is another question; I'm
interesting in finding out what was done to the 128k that
I grew up with (and still have) that has 1MB and definitely did
boot from an HD20 for much of its life, but wouldn't run
some games (notably, Prince of Persia) which needed
a Plus.
- Dave