[plug] GDI printers

[alan howard]

On Thu, 07 Sep 2000, Leon Brooks wrote:

> 
> > doesn't it? .  I thought the program and the internal software on the printers
> > microcontroller determined the action of various motors etc. The power supply
> > should be fairly safe except if a motor is driven to one of the limmits in the
> > mechanism and draws excess current.
> 
> This is usually prohibited by hardware (i.e. a switch). Older printers (e.g.
> Epson EX-1000) drove the stepper motors by wiggling bits on a port since at the
> time this was cheaper than a stepper-controller chip. These could be programmed
> to blow up a stepper motor. You could also switch on a pin solenoid in the head
> (or all pins) and leave it on, melting down the head. The GDI lasers have no
> pins, no "manual" control over steppers.

possibly, I have a old panasonic 9 pin dot matrix  ( not currently used) that
only can detect the print head home position, and as such would try to go to
the extreme right ( and beyond) when printing on some software with resulting
grones from the mechanism and motor. On this subject CD mechanisms also only
have a switch only on the home position ( TOC position) with no switch on the
outer position. If you get a faulty laser with either the E or F photo diode
faulty the tracking error signal can rise enough to make the transverse( sled)
servo drive the laser beyond the outer track position.

regards
alan howard