LA50 and Computest Docs wanted

Tony Duell ard.p850ug1 at
Tue May 7 12:21:19 CDT 2019

Firstly, does anyone have the printset (schematic) for the DEC LA50
printer? It's
not on Bitsavers and I can't find it anywhere else.

Secondly (and more interesting/less likely to be known) I have a thing here
called a 'Computest 3020'. It seems to be a luggable data logger. A case,
very deep from front to back, with a carrying handle. The front hinges down
and contains a keyboard, this reveals a monochrome monitor (about 9"
diagonal CRT) and a pair of half-height 5.25" Teac floppy drives.

Inside there's a logic board that slides in from the back. It contains a Z80A,
boot ROM, 64K DRAM, a pair of 8251 USARTs (oddly, only one is brought out
to a connector, there is a single DB25 on the back), Intel 8276 video chip,
Western Digital FDC (I think 2797, but don't quote me!) etc. It plugs in on
what seems to be separate sets of edge fingers for the floppy drives, keyboard,
monitor and a 50 wire link to the motherboard that is located above this
logic board. The motherboard has 8 edge connectors for '64 channel
switch' PCBs (look to be analogue multiplexers, full of 4052s), a 'measurement
PCB' (ADC, etc) and a 'control PCB' which I think is to control the thing you
are taking measurements from, it has 3 DE9 connectors).

Anyway, I can't find anything about it with Google. Manuals would be useful
the software disks (which I don't have) even more so.


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