Got a national wheel-o-vator lift that’s not running - model BC60, screw drive installed around 2012. Lift was running previously, although ran rough.... ran a few times then it would shutdown. Returned now and it’s shutdown and not moving at all. Safety circuit looks good, power ok, transformers and rectifiers good. Can’t get it to run still though, won’t even run off the board. I have pictures of the schematics and data plate but it won’t let me attach them (I assume since I’m doing this on my phone).

Does the Drive motor have a big capacitor mounted directly to the body of the motor? I have had issues in the past with that capacitor being blown up. Sometimes you can get lucky and just replace the capacitor. And it is a big can type capacitor you would also see in a garage door opener.

I can’t recall just what all is in the safety circuit other than stop switches (platform, under platform), but you’ve eliminated these;
Batteries?
Pan Switch?
Belt Switch?
Circuit Breakers?
That’s all I’ve got right now. Good luck.

Does the motor fire off? Will it lower if you jacked it up? Different problem solving for different "it won't rn" issues. If the lift won't fire in either direction I would recheck safety circuit, that was all I remember holding up a down call, beyond demand which I am guessing you simulated with the "off the board" comment.

update: found a bunch of issues to get it running. got it running but it would run real rough, basically starting and stopping rapidly the whole way - ended up finding the top final limit switch has the cover where the wires attach and inside that one of the screw terminals had come loose so that the vibration when running would cause the wire to make and break off that switch. got that back together correctly and now the thing runs like a champ. original issue to get it running looked to be a combination of loose wire in the controller coupled with an opening in the safety circuit. appreciate the help

YAAAAY!
Congratulations!
Now on to the next nightmare job!

Those are hard to find!!!

Great job. Good find.