26 Jan
2012
26 Jan
'12
12:07 a.m.
On Wed, Jan 25, 2012 at 4:19 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> Model III's and 4s are selling from between
$400 and $2400 on eBay. These=
Ouch!
I used an M3 for several years until I got an M4
(older version CPU board
without the large gate array chips -- the only custom part is the video
timing chain [1]). I've not found anything the M3 could do that I can't
also do on the M4, and the 80 column display and ability to run CP/M cabn
be useful.
When I was in High School, we had two TRS-80s for the "Computer Math"
class - an M3 and an M4. I did not know at the time about CP/M
options, so I ran some ordinary flavor of TRSDOS on them, whatever the
teacher handed us. ISTR preferring the M4 over the M3 when given the
opportunity, but it's been long enough that I can't remember why
(keyboard tactile feedback or monitor ripple or something trivial -
don't think it was software or firmware-related - we had the same OS
disks for both).
I should see about tracing down the memory fault on my M3 - I've tried
memory tests and moving the 4116s around, but it seems to only see 32K
of the 48K that's installed. It's possible that a '157 or something
further upstream from the DRAM is faulty.
-ethan