Tried it. turned on transmitter and then connected battery. Moved stick to lower right. Did not ARM. then moved stick up just a bit and it ARMs. Move stick back and it disarms (Sometimes). Wonder if there is some play in the transmitter sticks?
Go to the configuration to look at what exactly is happening with actual stick values on throttle and yaw when it won’t arm and when it does.
Unrelated to your problem but go to cli and paste this in. Enter - type save - enter
set min_throttle = 1050
set max_throttle = 2000
I also had an old radio that physically, when trying to arm, the stick bumps the bottom right corner of the gimbal housing. This would prevent the yaw value from going above the maxcheck value until I pushed the stick up a bit. If that’s the case on yours … Then we will go to the client and lower the value of maxcheck to something that is below a yaw value that you comfortably reach with the throttle all the way down. Again if I were a betting man, I’d put my money on your stick hitting the housing of your radio.
In cli (you know the procedure by now)
set max_check = 1950
those guys made a new and updated how to fly a drone video here: