Hit a power chord on my '72 Champ, and there was a fading of the chord about a second after I hit the chord, and flashes of light from the vent holes at the bottom of the output transformer. I was sick. I have purchased a Classic Tone output transformer, but hesitate to put it in until I find out was caused the failure. Volume was on 6, bass on 1, treble on 10. JJ 6V6-S power tube. 5Y3 rectifier and 12AX7 - all lit. No breaks in the speaker cable. I have 2 10" Oxfords wired in parallel to 5.7 ohms. About 3 months ago, I lifted the 15k resistor from the bass pot to prevent signal bleed off, and feed a stronger signal into the amp. I was under the impression that Leo did this to help keep the amp producing clean tones at higher volume back in the day. Today, removing that signal bleed path produces a much stronger signal into the tone stack/output transformer, which produces a *great* driven sound, sag/compression, rich sound. I was under the impression that this was a harmless mod. Could this have been the problem?