Judge dredd robotic arm fault

[new forest pinball]

hi all,
Have been asked to fix a robotic arm fault on a dredd . The fault is it continually runs from power up and never stops! Any ideas would be appreciated as I am not overly familiar with jd and it's a fair way from my place. So would be good to have some idea before I travel. Cheers Keith. (Thinking opto's.........)

 

[Moonraker]

Yes, optos. Best look at the manual on IPDB to give you an idea. It might be an alignment issue as they get knocked a fair bit when the playfield is lifted up.