My Hubsan X4 (H107) had developed a problem synchronizing with transmitter (tx to rx). Since I had to disassemble it completely and solder broken battery cable I wasn’t optimistic that I could fix it. But I knew the quadcopter was flying after my repairs, so I kept thinking that the problem may lay somewhere else.
I suspected the transmitter. Symptoms below were appearing in random order:
* Hubsan X4 established link to transmitter (LEDs on), but does not react to throttle
* Link is established, but drops immediately – LEDs flashing on quad-copter or LED flashing on transmitter
* Red LED flashing quickly on the transmitter
I tried all the usual IT magic: turn it off and on again, shake, press all buttons in random order and combinations etc. with no result. I tried to do the factory reset and recalibration – the transmitter did not respond to that. I needed to think outside of the box. And then it hit me!
The solution was (drumroll…) to change the batteries in transmitter.
The Hubsan X4 transmitter has a battery status build in, but it seems to be broken – it was showing more the batteries still have 3/5 of the juice while the batteries were clearly dead.