Pieter Palmers wrote:
Is the noise only present when printing, or also when the printer is
idle?
Noise is there whether the printer is turned on or not. It disappears
only when one or another of the cables are disconnected.
What you can do to test whether it is a ground loop is interrupting
the ground connection of the power plug (e.g. by wrapping some
non-conductive tape around the pin). If the noise stops, you have a
ground loop. Don't use this as a solution to your ground loop however,
as it is probably against regulations and is also pretty unsafe
regarding electric shocks.
If it is a ground loop, it is pretty difficult to solve. It's badly
designed hardware. You could try to plug your printer into the same
power outlet as the machine.
The printer is plugged into the same strip as the machine.
I tried lifting the ground, the noise was undiminished.
Next I'll try reprioritizing the interrupts, as soon as I can get
irqtune built. Or is there other software I should try ?
Linux 2.6 kernel, Debian Etch.
Best,
dp
