hey mike,
well i checked linde's website and that model or serial does not come up as a good number for me
it could be that i do not have access to the european trucks if they have another part of the site for those.
From the number you gave though this truck is a 1975 model truck, it is possible they do not have information that far back.
Maybe someone else can help that may have information on this unit.

But from your description of the problem i would check the switches in the accelerator pedal box and make sure they are all working, use a vom meter and check them.
Also check back at the contactors (the big electromagnet contacts as you put it) and see if they are even getting a signal to energise when the accel pedal is pressed. (you'll want to have the drive wheels jacked up off the floor for these tests) Each one will have 2 wires connected to each coil, check for voltage there and make sure they are getting a negative signal as well. Most systems today use negative switching but one that old may not.


good luck