VT220 keyboard (cont'd) - test-drb@ccmp.vtda.org

5 Oct 2008

Thanks for the replies, all, especially Tony Duell who had it
spot-on:

...
 This normally means there's a short in the keyboard
matrix, as if one key 
is stuck down.

What I would do is open up the keyboard casing (there are 2 screws under 
the plastic posts/feet) and remove the internals.  (snip)
...
 Connect the PCB to the terminal with the normal cable
and power up. Most 
likely the LEDs will go through the normal sequence and there'll be no 
error message, which shows the fault is in the keyboard itself. 
The LED's do indeed cycle when the isolated PCB is hooked up, and
eventually "VT220 OK" appears on the screen. So now I either have
to find the shorted key (it's pretty dirty in there so blowing
with compressed air might help) or just get another keyboard. I
won't try and wash it after reading the warnings here.

BTW I see one on ebag right now (190254818657) but it's a
"VT220-Style" unit, made by another manufacturer. Think it'd work
with a real VT220?

thanks
Charles