25 Oct
2007
25 Oct
'07
1:18 p.m.
The M4 first :
If you hold down the BREAK key while turning it on or pressing Reset
(Reset == the unmarked recessed button on the keyoard), it'll go into
Cassette BASIC. You'll get a CASS? prompt on the screen. Hit ENTER and
you'll get a MEMORY SIZE prompt. ENTER again and you're in BASIC. Of
course you can't use the disk drives, but at least it'll let you test the
system
Great help! I followed this and it's working! There's a sticker on the
front saying it has 128K of RAM. Can TR-DOS use all of it? I assume it's bank
selected somehow.
It is,. of course, bank-switched, along with the 14K BASIC ROMs and the
(2K) video memory.
IIRC, TRS-DOS only used 64K for running programs. The other 64K can be
used as a RAM disk.
For the M1 :
The EI (expansion interfce) is placed with the power button on the front
face and the 2 removable covers on top. The left-hand cover is held on by
4 screws, under that you can put an optional I/O board, normally a serial
port. It's likely to be empty. The right-hand cover is held on by 3
screws and covers a space to fit 2 power supplies, one for the EI and one
for the keyboard/CPU. The 2 supplies are indentical. At the front of this
space, on the PCB at the left side, is a 5 pin DIN socket. That takes the
output cable from the PSU used to power the EI.
Snip..
Again, great help. Mine does have the serial port board, but only one
power supply. I tried the one supply
with the model 1 but the LED on the keyboard flashes about once per
second, and nothing else (monitor