Sorry, I wrote this in a hurry and did not jot down all the specifics. So
here's
a update:

Demetri Kolokotronis <[log in to unmask]>
wrote:
> C.Itoh M-8510 did not respond when held Select key for three seconds as
> advised.

first set printer off-line then hold select key for 3 sec.s
if that doesn't work try holding select key while turning on power switch.

> Panasonic KX-P4420 produced no action except for indicating TNR CUP FULL
> U28. Do not know what key(s) to operate to perform self test.

there's a toner waste colection unit that needs to be replaced
before you can proceed with self test. It's usually a small gray bottle full
of
expended toner. You can try reusing the bottle after it's emptied, but first
look
to see if there's a small fuse. If you find a small fuse - you will need to
replace it
to use this bottle again. There's usually a spare kept on the developer unit
or
toner cartridge. Please do not save wasted toner - old toner has lost most
of its triboelectric charge and will cause more problems than it's worth.
>
> Have installed drivers for both on my computer. Print test page fails on
> both.
>
Did either printer show "on-line" status before trying to print?

> Do not understand "connect printer & pc together while unplugged, else
> you could loose the I/O or worse if your printer is slow to bleed the
> circuits". Unplug both printer and computer? Cannot just switch power
> off?
>
You can just turn the power off, then connect them. It's just wiser to
unplug
to minimize further problems while troubleshooting your current problem.
 Good luck -and don't hesitate to contact me for further help.
-yui

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