
ThanksYaaay!
Now I need to understand exactly what that wire did to see how it behaved as it did.
Can you identify which wire it is on the schematic?
There should be a junction marked on there as 18S goes to both the rectifier and also the screw terminal block at the bottom.
Was it missing to the rectifier or missing to the terminal block? (and therefore to the drive PCB)
View attachment 25051


One AC wire was connected to the bridge for each side, however, the additional ac wire coming from the bridge to the terminal which then splits off into another two wires, one to the motor board and lamp board was missing.So, the entire red wire there was missing, so the rectifier wasn't getting AC and neither was the brake lamp, or the motor drive?
I'm amazed and baffled so much worked.
One thing I noticed from the start, it's neither here nor there but I could never tell if an original motor board was working from day 1, meaning, there's no LED on the board anywhere, meaning the original design, yet the main pcb has a bright lit red led on it. One can measure I suppose but usually boards have a test points & lugs for voltages & some ground to work with, etc.Ah, ok, makes a bit more sense now as the brake wouldn't have released at all without the rectifier properly connected.
So somehow the motor drive PCB was working without 18VAC. What makes that odd is it needs to have a proper connection to power the optocouplers and chunky resistors on the sense circuit. It should theoretically have sat there doing nothing or juddering around, out-of-sync - that's certainly how my test rig behaves.
Oh well, best not to overthink it. Maybe somehow the lamp board put a weak 11V onto it instead. I'll figure it out some day perhaps![]()