I have an original Flextone XL.212 combo. It was working fine a few days ago, but now there is no sound coming out of the left speaker. Also, when I plug in headphones, there is no sound coming from the left side of the headphones as well. There is a strange popping coming from the left speaker as well, but as I said, the issue also occurs when i plug in headphones, so this leads me to believe it's not a blown speaker.  I believe this is a clue to the cause, but I have no idea. Could it be a fuse? What could it be? Help!!!!!!

Kev