HP 5190 flatbed scanner service info

does anyone have any service info for this scanner - schematics -
HP 5190 flatbed scanner service info - goes by model 5100cse


it has 3 voltages from power supply - all of which are ~10% low -
5v = 4.5v
12v - 10.8v
24v = 22.1v

when powered on scan light flashes once.
when connected to computer - WinXP - nothing is recognized.

tried reloading s/w & drivers - but computer doesn't see connection
no new hardware found message.
no imaging device in hardware manager.

was working - just stopped.

seems like parallel port busy line is active.
all other ports appear to have correct logic level at idle.

xtal oscillators appear to be running
uses a Motorola 6811 processor.

I have disconnected and reconnected all connectors and one plug in IC

thanks for your help
.