I didn't do invasive surgery on mine, instead I screwed two small servo screws into each side of the nose to look like twin machine guns pointing forward. I also carefully flexed the rear of the horizontal stabs downward to act as down elevator. This helped with a more level flight and also using careful throttle management. These light jets do not like very much head wind at all. In my first few flights in about 5 mph wind, I did a lot of walking to get the jet that was blown downwind.
Sounds like you fried something in the circuit. On your next one, try the external weights.