>I have the service manual for the 7475A if that would help at all.
>Don't have a working scanner handy but could probably borrow one -
>or even use this a legitimate reason to purchase one <grin>.

I would appreciate that Dwayne. Even though I believe I have managed to fix
the fault I would like to have it round. This thing is going to hang around
as there are no LabView drivers for the instrument to which we attach the
plotter, and the other alternative is to find a GPIB interface HP disk drive
to dump CSV files to. Not having one of those either then the plotter is the
only current way to get archive data off the instrument.

>The 7475 is a marvelous machine - the first one I purchased back in
>the mid '80s is still going strong.  I especially like the closed
>loop servo control system - HP managed to do an awful lot with a
>fairly simple micro.

Yeah when I got stuck in with a scope yesterday I began to appreciate just
how nice the servo system is. I have a 7470 at home which I believe is an
earlier version of the same plotter, so the circuits may come in handy there
as well, at least for getting the circuit concepts if I ever need to attack
it.

Despite modern laser printers and the like, somehow the plotter still
produces printout that seems to fit the bill, despite its slower speed, and
looks the part. Maybe this is just engineering geekiness :)))

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