APM will not arm, giving message "Arm- rotor not spinning

Me again with another question, Thanks to all in advance
I have already a 450 helicopter, apm 2.6, ver 3.2,.1Flysky th-9x flying fairly well thanks to all the help from the people on this forum, especially Chris.
I am trying to set up another 450 helicopter with a apm 2.6 board that was working fine on a quad I have. I have reset board to defaults twice, I have installed ver 3.2.1 heli , using the same wiring setup (Futaba style with ch 8 for ESC) as on my working heli, same Flysky th-9x. radio, same setup, no GPS, I have set no pre arm check in standard parameters.
Problem is APM will not arm, red flashing led will not go solid, in the flight data screen it gives the message “arm- rotor not spinning”?
I have also loaded ver 3.2.2 heli, same results no arm?
Here is another point, if I load ver 3.2.1 quad the apm arms fine, just like it should?
Any ideas what the problem is?

William, that message is false. It should say “rotor IS spinning”. You have a problem with your radio cal or setting on channel 8 with the particular receiver you have in the heli. It is seeing channel 8 as high and refusing to arm. I do not remember what the min value is before it thinks channel 8 is high. But that’s what you need to look at.

Thanks again Chris
Is there a parameter in mission planner I can adjust or is this a transmitter pwm rate problem?

It would appear to be a problem with the Channel 8 calibration. The software thinks the motor interlock is enabled so it refuses to arm. You could look at the radio calibration screen and see what the pwm value is with your governor switch off and with it on. It should be around 1000 pwm with it off.

Thanks Chris
I have no governor within ESC?
I reset, reloaded firmware a two or three different times and everything is OK