I picked-up a Philips L4X25T last week, cleaned it up, loaded it with 6 new C cells and crossed my fingers.. (didn't work this time). What I get is a tremendously loud tone around 500hz and no switch, control or any thing I wiggle inside affects it. Quite likely this thing is going to need some recapping, but it looks worth the effort. Since the tone seems somewhere around the speakers resonance, I thought I'd ask what are the chances that one of the TO-1 output transistors is bad? The schematic shows an output stage that looks very odd..