Dale,

Brilliant!  Until a few weeks ago I had 7475As stacked in my garage like
cordwood (gave 'em to a school).  I was planning on making a
photoplotter by using a blue LED modulated by the pen up/down solenoid
signals.  Plot on Kodalith (on a cardstock carrier) through an
aperture.  The ease and price of online PCB ordering/manufacturing kind
of makes the project moot.

Dave

Dale Botkin wrote:
>
> I used one for single sided boards with good results.  I hacked up a felt
> tip pen body to serve as a pen holder for a .5mm permanent marker from an
> art store.  The marker body was a tight friction fit in the modified HP
> pen body.  I removed the flip-up cover over the pen path (don't remember
> if I had to fake out a cover switch for this or not, but I think I did),
> set the plot speed to 1" o 2" per second, and taped the PCB material to a
> sheet of paper.  Plotting was slow, of course, but I had very good luck
> plotting direct to the board and etching it from there.  The key is
> getting the plotter to go slow enough to get good ink coverage from the
> permanent ink marker.
>
> Dale

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