We inheritted a problem that a competitor couldn't fix. Originally the drive contactors would drop out immediately upon engaging the accelerator switch. We've got the truck running but it PMTs frequently. We know that the problem is that the capacitor takes too long to charge and it is also loses its charge while driving as well as once the key switch is shut off.

Believe it or not these are the problems that we have found and fixed so far:
There was a hole in the insulation between the SCR panel and the heat sink
The main thyristor was bad.
The control card was bad
The left hand drive motor was burnt
The pump motor was shorted
There were no insulating washers on the bolts holding the SCR panel to the frame.
The power fuses were installed using steel washers not brass washers.

I know that any one of these problems would cause a truck to PMT and every one of them has been corrected but we still have not corrected the problem. I know the 24 volt version of this truck is finicky but this is ridiculous.
Any help is appreciated.