This is one of the most common failures of the early VDO controllers. We have fixed many of those controllers through two techniques; first resoldering the PC board and second replacing the capacitors. The capacitors are involved in the memory/timing sections.
Many of the rebuilders of these units add potentiometers to trim that function and a couple others; point of set and length of feedback loop.
I would also adjust the slack in the control cable as these are often very loose, which places the actuator at its end of stroke; where it has less control.
Owner 24 bay BSC
Bosch Master, ASE master L1
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