Been checking out the motor connections, all 3 motor windings measure around 13 Ohms measured at the Motor Drive board via the commoned end of the motor windings that connect to the +9.7V supply, so look good.
Not able to get good readings across the 3 motor distributer contacts, on the schematic and in description 2 of the contacts should be grounded and as the motor rotates the grounded pair should cycle around the 3 contacts. Not able to measure any of the contacts being properly grounded, mainly hundreds of Ohms but nothing consistent at all. Measured the ground connection is getting to the motor at terminal 4. So looks like there may be a problem with these contacts but somewhat loath to go inside the motor to check as looks so difficult but may have no option.
Struggling at the moment to measure the +9.7V supply at the Motor Drive board, there must be voltage there because the motor does rotate sometimes, think just bad meter connections, everything is so awkward to get onto, made more difficult by having to press down K3 to get power on.
Uncle Bulgaria - How does the motor drive pulley come off the motor shaft ? and how do the black end caps come off the motor. From your motor photos I assume the 3 contacts are the sprung loaded pins that make contact with the 3 copper segments in the end cap. I think I am going to have to bite the bullet and remove the motor for disassembly to inspect the contacts but first will check the motor drive signals and contacts voltage wise when the motor runs
David