Schematics/diagram for a BP Series II

Hello All,

I find myself in need of locating an electrical diagram/schematics
for a manual BP series II.

The factory has been no help according to the owner. The motors are
not responding to the controls and I need a diagram to try to
determine why.

Can any one help? Best guess is the machine is around 20 years old
{probably more) with a huge electrical box on the back.

Thanks,

Donald Brock