Gen 1 z mainboard and v2 problem

[57?48]

So I just finished my first mainboard swap and installed a v2, but when I tried it out it didn't work right. The throttle works fine, the motor goes forwards, backwards and it can move at different speeds, but sometimes when I turn off the remote while the xmod is still on, the motor will run on its own and the v2 gets a bit warm(but never hot). Any ideas of what might be wrong? Anyone have any pics I can use for comparison. If it makes a difference, I soldered some of the wires to the testing thing(dunno what it's called) on the v2 cuz I don't have small enough wire for the normal connections.

Edit: Servo just keeps running in one direction when I turn it on.