5 Mar
2013
5 Mar
'13
5:22 p.m.
On 03/05/2013 01:45 PM, MikeS wrote:
----- Original Message ----- Date: Tue, 5 Mar 2013
18:38:53 +1100
From: Doug Jackson <doug at doughq.com>
Hi,
I have recently received and repaired a TRS-80 Model 200 machine. Woot!
My query is if anybody has any experience in adding extra memory - I note
that it has some sockets under it for memory expansion, but the
recommended
devices are 24k (A ceramic carrier with 3 x 8K chips and some decoding -
Has anybody had experience using 62256 or similar parts?
----- Reply:
Hi Doug,
The Club100 list would probably be a better place to ask; I think
Steve will
be able to help you out.
How'd you make out with that ROM upgrade I sent you?
mike
I did it in my M100, used a 62256 and external decode on a piggyback board.
There was enough room if sockets were not used. It used the open sockets
for the IOand mechanical support. Its a fairly simple thing to do.
I believe someone else did it and documented theirs on the Club100 site.
I later modded mine for 64K ram and phantom rom. The default is the M100
rom,
the alternate loads CP/M into ram and boots it. disk is a old 16meg CF
tucked in
there. This is not so trivial as the drivers for the keyboard and
display are
a PITA. Initial work was done using the serial port as a console and
running
debug code for the keyboard and display.
Allison