25 Jan
2011
25 Jan
'11
2:11 p.m.
On 25 January 2011 20:18, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Yup, the machine has a TV-out as well as the standard monitor. The PAL
board is marked as such and has a colour modulator on it.
Folks,
Picked up one of these wee beasts today at long last, Z80 CP/M and CP/N
machine from ~1981, complete with not-oft-spotted hi-res colour PAL boards
The H-res board is not that rare. The PAL enocder is, if you have that. Is this the 5.25" floppy version or the 8"?
I thought the former normally
5.25". I've only ever heard talk of the 8"
had the drives in the processor box, in which case the
cabel is internal
(but you say you've not dismantled it). The floppy controller is based on
a 1771, and has a standard Shugart-ish interface for the drives.
Yup, hence me raiding my store of Cumanas :)
backplane/motehrboard. Other cables plug into these
boards too, going to
the flppy drives and the rear panel connectotrs. ?The text video board
connects to the CPU board by a special cable (soldered to the video board)
I remembered the internal layout from school. This machine has a
perspex top cover so it's been dismantled and visually checked for
damaged components, looks ok.
The PSU output to all the cards is carried by a tiny
10 way ribbon cable
and connecotr that plugs into the CPU board. Power between the PCBs is
carried along the bus ribbon cable. I don't like it!
I guessed that, there's 2 ribbon cables that come out of the PSU as
well as the separate feed for the floppy drives.
Waht I would do, due to the possible dampness
problems, is to check the
earth continuity and the insulation resistance (the latter with a megger,
preferably 1000V) Assuming it all checks out, apply mains and check the
PSU output voltages. Then set up the minimal system (CPU + text video
boards, linked to a composite monitor ans see if you can ge the COS
prompt (COS == Cassette Operating System, of course). Then assemble the
complte machine nnd try to boot it
I should be able to get a Megger at work. The reason I mention the
caps is because the last 3 or 4 machines I've had in have all blown
the mains filters.
Watch this space!
Cheers,
--
adrian/witchy
Owner of Binary Dinosaurs, the UK's biggest home computer collection?
www.binarydinosaurs.co.uk