TRS-80 Model II, xwhatsit Model F to USB

[OldIsNew]

After XMIT  mentioned on another thread that he thought it was likely that the xwhatsit would work with KeyTronic foam and foil boards since they're capacitive like the Model F, I definitely wanted to try it and it works like a charm. I used the xwhatsit on a Westinghouse KeyTronic board with good results and this one is a TRS-80 Model II board. The case is somewhat flimsy plastic but I like the look and  internally it's a "vintage" KeyTronic foam and foil.

         


The old foam and foil had degraded as usual so I replaced it:

         


Mapping the matrix is easy with these boards since they have such nice big conductive pads and it's just a matter of using a continuity tester to figure out which pads are connected to each other.
After that just recorded which IC pin  corresponded to which row/column.  Then desoldered the ICs and wired the xwhatsit to the pads.

         

It's not even necessary to keep track of which PCB pads correspond to which keys since that all gets assigned in the xwhatsit Capsense Keyboard Utility.




Interestingly the matrix on this board was 8 rows  x 12 columns which was the same as the Westinghouse KeyTronic board.  If it happens that KeyTronic stuck to the 8 rows by "x" column pattern then I would imagine almost any KeyTronic foam and foil could use the xwhatsit since the xwhatsit Model F can accommodate up to 8 rows by 16 columns.  I have another KeyTronic PCB left over from another project and I'll probably trace that out to see if it fits the pattern.

I also sanded and repainted the case because it was a bit of a mess.

                   

This board is working well with the voltage threshold set at 193 (typing this with it) . I never got a TRS-80 back in the day because they were quite expensive and, as my father said, "Nobody needs a computer in their house!" At least I have a keyboard now.

[dorkvader]

Wow this is awesome! I love mods like this. Maybe I'll add a controller to one of my old Keytronic boards.

I love all the guard traces they have on the PCB to prevent leakage.

Now I dont think these were all that great to type on: any thoughts?

[OldIsNew]

I love all the guard traces they have on the PCB to prevent leakage.

I do think it is a nice touch - someone put some thought into the board.

Now I dont think these were all that great to type on: any thoughts?

I like the switches actually. At least on the three older KeyTronic boards I have, I find the switches to be nice smooth linears. I really do like typing on them.

[wolf]

OMFG!  This is a bigger nostalgia trip than a K-TEL record!  I remember the "Trash Eighty" from back in the day - never was in the financial league to buy one but I had rich friends who had them.

What a fantastic restoration/upgrade/modernisation project!

I remember having to repair an old foam and foil keyboard back in the eighties by gluing bits of aluminium foil onto pieces of foam cut to size - never had to do the whole board, though, just a couple of keys at a time.  IIRC, I've got an old foam and foil board around here somewhere in my junk pile - doesn't date back to 1979, though.