I'm having a problem with a Personal LaserWriter NT. At power-up, with
nothing connected to the printer, all three LEDs come on briefly, then they
go out, and the paper-out LED starts flashing.
The manual indicates this means the printer is waiting for manual-feed
paper, but obviously it shouldn't be. The engine test prints a normal test
sheet.
It sounds like the I/O board needs replacing, especially if you can get a good
engine self-test out of the printer. We recommend replacing the board for
test purposes.