6 Nov
2004
6 Nov
'04
2:38 p.m.
1) This machines has a large board on top of the
mainboard - this board plugs
into the Z80 socket (the Z80 moves to the top board), as well as a ROM
socket and the monitor connector - there is also a bunch of "flying leads"
which connect to various points on the mainboard and attach to a socket/header
on the top board...
Can anyone tell me what this board is? Is it "normal" on an Osborne-1?
Neither of my 1A's have this board, and the mainboard appears to be the same...
Is it perhaps an upgrade of some kind?
2) Has anyone disassembled or otherwise obtained source code to the Osborne
boot ROM - I would like to try and figure out how far the machine is getting,
and what it is doing when it restarts.
3) Has anyone seen this behaviour in an Osborne before?
Ok - I've figured just about everything out! ...
The board on top is an 80 column adapter.
The Boot rom listings are in the technical manual (duh!)
The problem with this Osborne is the keyboard! - It is apparently sending a
false key, which is causing the O1 to clear/redraw the screen.
Unfortunately, the keyboard does not look very servicable ... anyone successfully
fixed one of these things? (membrane matrix).
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Vintage computing equipment collector.
http://www.parse.com/~ddunfield/museum/index.html