Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Robert Hedan <robert.hedan@...>
wrote:

> What's that thin transparency strip used for?  I figure it's for motion
> control, but how does it work?  It seems uniform grey colour, but I
think it
> must be more than that, is it magnetized film with position markers?
 Or is
> it more of an optical device (my eyes can't make out lines, and I
don't want
> to touch it)?

Chris is correct, it is an optical encoding strip. Clear plastic with
black lines printed on it.

> I'm looking at what would be required to lift the printhead chariot by
> 1/16".  So far I've determined that the drive strap would most
likely not
> require displacement.  That darkened strip might still be within sensor
> range, tests required.  The front guide rail just requires a 1/16"
spacer on
> the 'skate'.
> 
> The main obstacle is that rear guide rail, the printhead is clipped
around
> it.  One possible solution is to trim the bottom of the clip 1/16" and
> adding a 1/16" shim at the top of the clip.  I haven't taken the chariot
> apart yet, but the more I look at it, the more I think it would be
possible
> to modify this printer to accurately process 1/16" PCB.

Some people have modified their printers to accept CDs. That's roughly
the thickness of a PCB. I don't think they moved the print head up, at
least not in the way you are suggesting.

The C84 is hampered by not having a paper thickness lever.

Steve Greenfield