Keyboard woes

[Mike Tweedie]

Hi all...

I got a used Apple Pro keyboard today, and before I use it to prop open a
door, I thought I would ask the group.

It sort of works initially, as long as I push the keys hard enough. Then,
after about 2 minutes, I get nothing at all. Is this a fault in the kb, the
USB cable or the add-on USB card I have in this machine?

BTW, this is an old G3 Desktop with a G4/450.

TIA
Mike