Hi y'all! First post here--be easy on me. Following the tech question format stated at top of the forum. If any more information is needed, please let me know. (1) AMP: 1994 Fender Blues Deville 2x12 (2) PROBLEM: Something utterly dreadful is happening with my amp. I've had it for about eight years now and this is the first time I've seen an issue. Randomly while playing, the amp makes God awful noises that are hard to describe. Screeches and loud pops and more -- it's a freakin' circus. I took it to my amp guy to get it fixed up. He tested every connection, checked every solder. Everything looks solid. We tried swapping out power tubes; no dice. Swapped pre-amp tubes; even less dice. He and I are both at a loss. (3)SCHEMATIC: http://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-Blues-Deville-Schematic.pdf Only a single mod on this amp--linear to audio taper. Everything else seems in tip-top shape. If it'd help, I could provide an audio recording of the noise? No idea what to do here. Someone help?