I have a second user Dell Optiplex GX1 machine. The USB ports used to be fine,
but then one of them became physically damaged, possibly generating shorts
between pins and/or case when cable was attempted to be plugged in to it. Now
neither of the USB ports will work.

A check revealed that there was no 5V on the usual pin of either socket. I have
connected this pin internally to a 5V rail, but there is still no communication
between PC and the USB device (printer). The Win98 USB drivers are reported to
be working and AFAIK, USB is permanently enabled on these machines - there is
no jumper or setting in the BIOS to disable them.

I'm guessing that the USB interface chip must be damaged, although I can't
actually locate anything that does this function. The only chips near the
socket are a pair of NE555 timers and what might be an op-amp. Is there anyone
here who is familiar with the innards of this machine who can throw any light
on this interface please?

Otherwise I think I'll have to put in a PCI card with USB ports on it to use
instead. Cheap enough solution, but is this likely to be a problem given that I
can't disable the onboard USB ports, even though they don't work, please?


Malcolm (Fantrace).

Be happy.