It looks like the motor controller IC is not generating the second Vcore supply. That's either because it is faulty, or because it is not being told to turn it on.
The drive does have a terminal port which outputs diagnostic messages, but you would need to purchase a 1.8V TTL-USB adapter.
There are three other ICs (MOSFETs) which perform voltage switching. If you can locate the 3 motor pins (connector J7), there are two ICs nearby, one 8-pin and one 6-pin. Measure the voltages at each pin. Many pins will be connected together, so you only need to measure one from each group. You should measure +5V or +12V (I don't know which).
There is another 6-pin MOSFET to the left of the 5V e-fuse. Measure its pins also. Be careful not to short pin #3 to its adjacent pin. Likewise for the other two MOSFETs.
There is a small white shock sensor near one of the screw holes. There is an inductor nearby, and above it is a diode. Measure the voltage between the anode of the diode (non-striped end) and ground. If this voltage is being turned on, it will probably be -5V (or maybe -3V).