This equipment (a Microgrid III 36" x 48" graphics digitizing tablet ca 1992)
is a tad esoteric at this point..no factory service, tech manual available,
etc. I'm a student trying to resurrect this old bird for my GIS classes.

Serial interfacing software (Vtablet) is available for connecting this to my
XP Pro Compaq laptop. I bought a serial port to USB adapter (Keyspan) for my
MGIII which self-installed at COM5. Since the COM1 port was occupied, I reset
the serial Keyspan adapter via the Windows Device Manager to COM2 and set
Vtablet to COM2 as well. Following recommended start-up procedure (Microgrid
tablet on, then boot) I am unable to elicit any puck output (screen cursor
movement in response to moving the puck on the tablet) which is also
confirmed as zero port interrupts on the software's Status tab.

I am now concerned that the tablet controller is misbehaving . I also note
that the Microgrid start-up only produces two tones instead of the €œall okay€�
three tone self-diagnostic (don't know the implication of the missing tone).

The unit has a removable 8" x 13" controller board and I was wondering if
anyone out there could direct me to an circuit troubleshooter who could look
it over and hopefully repair???

Many thanks!