Problems setting up a nitro Heli with external gov

Hi there, I'm having trouble setting up a Gaui Nx4 with separate governor and ar7200bx. I own a devo 8s 12s and 7e and want to fly this heli with the 12s.
I have bound to the ar7200bx and have control over all cyclic servo and have set limits to the throttle servo so that it does not bind. My problem is that today I switched on my transmitter, and I no longer have control of the throttle servo in any flight mode..it is energised and centered it just will not respond to throttle inputs from the transmitter. The governor is powered from the throttle port on the ar7200bx and the servo is plugged into an output on the governor.I have a linear throttle curve in normal and and a v curve in idle 1 and 2. I did have control of the throttle servo this morning and my post was going to be about how to set the governor control on my transmitter on ch 7 but unfortunately I have lost the control of the servo so hence this post. Any help will be appreciated.. all I get from from mates at the field is "crap chinese radio get a DX8" I know these radios have the abilities.it's just I don't.....yet!

I think your problem is with the AR7200bx. I just pit one on my 450pro and could not figure out why the esc would not initialize. There is a few steps of setup that you have to do with ar7200bx so that it safely manages the throttle signal. The problem is I cant remember the steps off the top of my head.

If you google "ar7200bx and esc problem" you will find a helpfull description of how to get it setup on one of the helifreak forums.

It appears you are correct..I reset the endpoint of the throttle servo to -100 and I now have full control of the servo. I adjusted the ball on the throttle servo so now it has less range and will not bind in the negative values which was stopping me adjusting the travel of this servo correctly. Right problem one solved.. now to problem two..throttle cut and governor setup.. any ideas anyone..this is my first nitro so any help would be greatly appreciated.

Im not a nitro guy either, but i see guys waste countless hours/days trying to get the thing started or keep it running. Actually, those problems I see more with nitor planes but it was enough to turn me off from nitro gear completely.

Your throttle cut will have to be set to compensate for trim. Most nitro helis end up using the trim on the throttle to set the idle point at low stick. If i had a nitro heli I would set my hold/cut in two stages. Or program it on a two position switch. The first position would hold the throttle at the idle point, and the second stage would cut throttle off completly. That would come in handy for practicing auto-rotations, or wanting to do setup and not have to kill the motor.

The new ar720bx gov feature is a comlpete mystery to me, and I can help with that. You will most likely find better info on Helifreak forum. Then when you have a better idea of what settings you need in your tx, you can get that help here.

Thanks for the pointers, I have managed to maiden the NX4 today, for reference for anyone else having problems. I setup the throttle so that the horns where parallel throughout their travel and with the Gaui govenor I set high and low points. I used aux 2 on the ar7200bx and had to go into the complex mixer to assign the values to the various flight mode switches. Not too difficult..small steps setting a fixed value to the switch positions. I had to reverse the channel to get the green light on the governor, but it all seems to work ok.. I just need to tach it to get the values correct, now the hard work is done..

Got the governor all set up, I've had to keep the advanced mixer screen, because if I switch back it messes all the settings up and I have to start again. Changed channel 7 to an expo curve linked to the fmode switch positions, the same as the gyro gain values screen. it works really well now. The only thing I'm missing is a throttle cut switch. I'd like to assign this to the trainer switch on my 12s..It would just be an instantaneous value of about -80 on ch 7..unfortunately I have no idea how to implement it....any help anyone?

edit..

Right figured it out..I had to add another mixer to the throttle channel..mixer 4 (other 3 do throttle curves.) trn1 switch fixed value -120..job done..easy really..small steps..