i have a SimpleBCG 8Bit Controller with YAW Extension Board. Everything worked fine. On the 4th TestRun The Gimbal stopped working immediately, so Motors stopped and all Leds / Lights went off. Also a Reconect of a Full Battery did not help. It looks dead.
But when i connect USB Everythink looks normal (Connection, i can Calibrate, get all Sensor Datas and so on). But when i reonnect battery only (Without USB) , the board is dead again.
So on Battery = Dead Board on USB = Everything looks fine Everything works.
this was my first thougt but soldering is ok, also the plug, i get 12.2 volts on the Battery Ports (Solder Points). IS there any fuse or even voltage regulator burned?
I had virtually the same symptoms.... Except I saw the small chip next to the battery wire go red hot for a second then that was it... no battery power but usb seemed ok but it was fried all the same. Hobby king are sending me a replacement.