My dad has a Blues Junior that he's been experiencing problems with lately. It seems specific to G notes only. When he plays the note, I can hear ticking in the back of the amp near the PCB, and then the amp pops and the volume drops out. I've searched around on the Fender Forum (BJ Mafia) and all over Google, but haven't really found anything. People even went to respond to the problem by saying "don't play a G note," which is ridiculous and ignorant. FWIW, he just had the amp retubed, and they don't show any signs of failure and/or problems. The speaker is also installed correctly and the input jack is tight and clean.