IBM F122 keyboard grounding issues?

[Frank44]

Hi all, I recently bought a IBM F122 keyboard (battelship). I disassembled it, put new foam in it, cleaned everything, bought a converter, did a flos mod and now it works. In fact, I am typing on it now. The only problem is that it isn't back in its case yet. Every time I put it back on its base plate, random characters appear on the screen. It's a big mess of characters which makes the keyboard completely useless. When I detach it from the plate, it works again like it should. I guess it must be a grounding issue, but how can I solve it?

Other IBM keyboards have seperate grounding cables, but this one doesn't, so I don't know what to do. Any suggestions? Thanks!

[fohat.digs]

Leave it out! Ha Ha I prefer mine naked like that.

But seriously, check to make sure that there is no binding and/or that the case is not touching any of the key caps - it happens more than you might think.

[zegonix]

i don't know this keyboard so my suggestions might not make any sense. but assuming, the pcb has components on the bottom, have you tried putting a nonconductive layer between pcb and case? if that doesn't work, i would support you assumption and try measuring the potential of the case when connected.