Ninebot F20 won't go - no speed shown

[Comatose]

Hello, hoping to get some help

F20 won't go. I have replaced the throttle, but reluctant to buy more parts until I can troubleshoot some more.
Has power, connects to Bluetooth and is activated.

I managed to get it going by discounting the battery and turning it on to discharge capacitors.

I rode it up and down the street and put it away.
Since then I have not been able to get it going again.

Removing the motor revealed no hall sensors for speed determination. Seems the F Series has a different way of determining speed.
Does the F series need to detect that you are moving before the throttle works?

Any suggestions? Thanks