If it has the old Autohelm, (+10,-10,+1,-1, Standby and Auto buttons) then
it maybe the same as the control head for all the older AH units.

I have the schematic for that control unit on my web site at
http://hood.hctc.com/~esteve/private/manuals/

If not, the circuits may be similar enough to do some trouble shooting.

Steve
s/v Good Intentions