On Wed, 4 Mar 1998, Marty wrote:
> I've got the Sol-20 up where I can see the monitor prompt '>' but
> there is garbage on the screen which I have yet been able to get rid
> of and attempts to load off a cpm diskette (that came with this
> package) have failed thus far.
Is the keyboard working properly? The Sol-20 keyboard is a capacitive
unit in which pressing a key pushes the insulated side of a piece of
one-size metallized Mylar film against plates on the printed circuit
board, changing the capacitance. These pieces of film are attached to the
key mechanism with foam. Over the course of time, this foam
disintegrates, the metal backing mysteriously disappears from the film,
and pieces become detached from the keys and rattle around inside the
keyboard wreaking havoc.
If you are having problems with the keyboard (or the garbage on your
screen looks like it could be the result of stuck keys), you may want to
check for this problem. The PC board is held to the keyboard assembly
with screws and is easily removed. After removing the keyboard assembly,
you can test the machine by using parts salvaged from another capacitive
keyboard (or even a piece of foil held behind thin plastic) to complete
the "key capacitors". There are instructions somewhere on the classiccmp
archive for rebuilding a Sol-20 keyboard using a PC-clone (Keytronics?)
capacitive keyboard as a donor. It's on my relatively long list of things
to do.
--
Scott Ware ware_at_xtal.pharm.nwu.edu
Received on Wed Mar 04 1998 - 10:04:05 GMT