Unfortunately I had a mono headphone on when poking around

If you plug a mono headphone into a stereo jack you will short out one of the channels.
SG

 

Yes use an external amp to probe the output of the headphone amp chip , it could be the socket wiring or the input signal.

 

Ok. I tested both Out A and Out B on the chip to an amp and theyre both fine.

Could it be the component at Q6? Labelled 6B. Someone said its a muting transistor and maybe it blew when I used mono headphones.

 

So the amp is ok, then follow the tracks to the headphone socket.

 

Ok so the amp is ok, then follow the tracks to the headphone socket.

Are you using a stereo headphone?
SG

 

Usually, in a repair shop we would be using an oscilloscope to trace where the signal is going.
With no oscilloscope at hand a second-rate substitute would be an audio amplifier such as a PC audio amp.
I will assume that you know the part number of the headphone amplifier and that you have access to the circuit diagram. Best of all is to have the circuit diagram on the actual device, i.e. the drum kit.

Is the circuit on post #2 an accurate representation of your circuit?

 

Right. I think I have it fixed now. Apparently the trace for the Left wasn't reaching the L1 point so I put a wire to it and now I get Left channel (see photos)! Huzzah!

Appreciate everyone's help.