Thanks for posting the pics! Good pics!
Check the little black part near "D8". It's on the back side near the white plastic base of the right trigger. It's a little black part with three silver legs. One of the silver legs has a glob of solder on it still. That solder might be connecting the leg of the D8 diode to the ground plain. This particular circuit board has a ground plain (I think) which is pretty common of circuit boards. Basically any part of the circuit board that isn't use for other copper traces may be connected to the ground plain (which is the same as ground). Some reasons for using a ground plain include heat dissipation and lower production costs (less etching of the copper, meaning longer life of the chemicals used, etc.)
I will keep looking over the pics but that was the first thing that stood out. Try using your iron to clean that solder off.
Check the little black part near "D8". It's on the back side near the white plastic base of the right trigger. It's a little black part with three silver legs. One of the silver legs has a glob of solder on it still. That solder might be connecting the leg of the D8 diode to the ground plain. This particular circuit board has a ground plain (I think) which is pretty common of circuit boards. Basically any part of the circuit board that isn't use for other copper traces may be connected to the ground plain (which is the same as ground). Some reasons for using a ground plain include heat dissipation and lower production costs (less etching of the copper, meaning longer life of the chemicals used, etc.)
I will keep looking over the pics but that was the first thing that stood out. Try using your iron to clean that solder off.