Autohelm 1000 tiller pilot circuit info

[sailerjim]

Hi
I have one of these, its a digital 1000. I'm technical and trying to repair it.
I could use circuit and timing info. The unit blows the drive transistors in auto but only randomly. One thing I've noticed is that when i hit the one degree button it drives the control arm as much as if the ten degree button is hit, in both directions btw. this might be a symptom. any help appreciated.