I have had very good success with this UMAX scanner
running under WIN98 SE, connected to LPT1 and sharing a LPT port with
HP5P Laser printer.

Now, only recently, and now frequently,
instead of performing warmup, running lamp back and forth, "unlock
your scanner" message appears and the lamp is stalled at top of form.
OR sometimes the lamp will stall at bottom of form. ALL scanner
softwares cannot cause lamp to return to top of form, often see message
"scanner is busy".

Only way I can make scanner operational again, is
disconnect all scanner cables, power down then power on, reboot the PC
without scanner.
Then reconnect all cables. Reboot PC with scanner and run a 'scanner
test'. Sometimes scanner lamp will move but scanner is still not OK.
Scanner test drives lamp to bottom of page and the lamp stalls. "scanner
is busy" is message.
Usually, removing cables again, several reboots,
will bring the scanner back to working again FOR A WHILE.

I sure can use some suggestions.

Is this a scanner problem? Dust in Scanner?
Can I do any safe maintenance on scanner by removing plastic case?

Or, is a PC LPT1 printer port problem?
Or, is it an incorrect LPT1 port setting?

Printer is working just fine.

Thank you for any hints.
Dave