HP 612C (Linux) resume light flashes

The Power light is steady; according to the paper manual, this light
combination indicates a mis-installed cartridge, or an open cover, or
an empty paper tray. (None of these conditions are true). The manual
also says:

"Press Resume to clear the error condition. Then check your computer
screen for any reported error message and corrective action instructions."

Pressing Resume does nothing (the light continues to flash), but if I
cycle power, the light goes out, only to begin flashing again when I
send another print job to it. It acts the same whether I send a
postscript file or plain ascii.

Since I'm running Linux, I can't get any info from the HP software
mentioned in the manuals, but there are no errors reported by X or
Ghostscript. What other possible errors can cause this light to flash?
What would the HP software tell me, if I could run it?

Both ink cartridges are new, and I have printed several sheets
sucessfully since installing them, so I'm confident they're
functional. The thing was printing just fine from LyX, after the new
cartridges went in, until the following happened:

My wife accidentally clicked an icon on her desktop, intending to
move it, to tidy the look, when the printer began printing a text
file, apparently one of the KDE applnk files. To stop it, she
removed all the paper from the tray, and after the printer ejected
the one sheet it printed, she switched off the power. That was the
last thing the printer would print.

My question is: can some code become stuck in this model printer
that survives power cycling and power disconnection? If so, how do I
clear it?

I've rechecked the ink cartridges, and the paper supply and watched
the ink holder move around with the cover raised. All the whirring
sounds seem normal up to the point where everything stops and the
light begins flashing. I don't know what else to try.

System details: SuSE Linux 7.3, kernel upgraded to 2.4.23,
Ghostscript 6.51, KDE 2.something, Apsfilter 7.2.5 (not the SuSE version)


TIA,

Jim