I have a jet powered with the professional. Use 7 mks 737 servo's. The problem I have is every time I power up the powerbox the servo's have a small disposition. Especially the flaps, they use 1 servo for each flap. I did a firmware check and it is V3. Did the complete process to setup mechanically and transmitter for the master servo and init the slave in the centre position followed by the endpoints. After setup everything is allright. After power cycle I have different positions of the servo's. Most of the time it is the slave servo. What can I do?