Fairlight-CMI

> My graphics pen is extremely inaccurate when the Fairlight is first booted
> up, but ONLY when the pen button is being pressed.

Have you tried the pad on a different unit to determine that the problem
is really with the pad, rather than the interface in the mainframe ?

What if you use the button repeatedly, does it improve ?  (corrosion on
the contacts of the button).

What if you hold the button and move the cable a bit, does it become worse ?

>  After a while it will settle, but if it hasn't been used for 5 mins or
> so, it will become unstable again. I've tried cleaning the pad and the
> pen, but probably assume the pen is faulty.

It could be the cable.

Regards,
Harald.