My attempts to solve a power fading problem on my Viking Eco Stepper

[oldgroaner]

The first step was to dismantle the cover over the controller and attempt to understand the many wires.
I first checked the connector to the motor and finding only three leads concluded it was one without Hall effect sensors, so began looking at the mass of wires.
Two were unused


The power leads were easy to locate



As were the three leads to the Motor

The brakes were proved by checking with a multimeter, they give a dead short when the levers are pulled

Two sets of wires switched out the Display when either disconnected and were in a common sheath

There remaining twin and single lead were separate but in the same sleeve and seem to be the PAS sender

The PAS sensor is under the bottom bracket and sopping wet, and by heating it with a hair drier I was able to temporarily restore motor operation as normal, but this faded after a mile or so, so I have sent for a replacement PAS sensor to see if I have made the correct diagnosis.
I have included these stages in the hope they will help any other newbie like me when baffled by the mass of wiring and not certain how to find out what they do, as you can't seem to find a wiring schematic anywhere on the net.

 

[oldgroaner]

While waiting for the PAS sensor to come i bought a lock ring C spanner and a crank puller as i knew they would be needed to change the sensor, when i tried them the rotating sensor disc teeth that deform to lock it to the axle all fell out!
For the moment it is held in place with Blu Tak till the replacement disc I have sent for today arrives.
Interestingly it works very well!