Problem with the spektrum port
Some versions of the controllers can have a problem with the spektrum port: the satellite receiver does not get enough power from the 3.3V internal voltage regulator, resulting in unstable operation (symptoms: signal interrupts, LED blinks randomly, on binding attempt system goes to reset).
1. To power the receiver from the external 3.3v power source.
2. To solder additional 3.3v LDO regulator into the controller. The best choice is 3-lead TO-92 package (for example, LP2950-33, L4931CZ33-AP, L78L33-ACZ). Soldering additional LDO voltage regulator 3.3v