Thread resurrection and a new forum member here.
I have the same equipment as the OP was having problems with, also bought 2nd hand, and I also need help with a problem.
Bike is a single-speed no-name unit with a "Super" torque-sensing crank, AKM-13.0 rear hub motor and CK-01 display. The crank unit appears to include the controller. It has two leads running into it - one from the display and battery (6-pin), the other to the motor (9-pin)
When I pedal with minimal force, the assist seems to work fine. When I apply slightly more pedal pressure, the assist seems to die off. So, kind of "anti-torque assist".
The display has a 5 stage assist. In the menu settings you can adjust the sensitivity of the motor assitance eg level 01 cuts the assistance in ealry, 20 cuts in it late and hardly at all. This adjustment ALSO impacts the speedo - as the selected level for sensitivity increases, the speedo reads lower. It only appears to be accurate at the 01 setting.
I'm after either or both of two things:
My background is in automotive electrical and electronics so the basics of the kit don't phase me too much, I have meters and a 'scope that I can use to measure and test etc. What I lack is a solid understanding of how this system is MEANT to function, what signals to look for where and when etc. So, basic system operation and fundemental system testing processes is my first want.
Failing that, someone who has struck this problem before and can give me the quick fix solution!
Worth noting I am in New Zealand - the ass end of the world and about a zillion-years away from any decent supply chain. I don't get to just nip down to the local dealer and ask for some plug-in bits to try out. So "replacement testing" is not an option.
Cheers all - help me out!