I built one a few years ago, and I completely agree with Chuck's impression that it sounds very good. Brilliance and (misspeled) Treble are incorrectly labeled. Might be time for a makeover with some better selected fets
Checking voltages and trying to trace the audio with the probe are steps that I would take, as well.
Bear in mind that the LED turning on and off does not mean, necessarily, that the relay is working, as it depends on the 555 chip.
Built a bellows with a couple 2n3904's forming a darlington pair instead of the MPSA13. Really nice distortion and fuzz tones (and some cool overdrive tones, too). Very simple circuit, but really effective.
The service manual of the amplifier dictates 15v on the drain of the first jfet and 11.5V on the drain of the second one. I don't know what exactly is the ouput of the charge pump, but you should go for roughly 60% and 50% of VEE.
Thanks for taking a look, Chuck! From what I could find, it sounds really sweet. From clean to pretty overdriven. I'm kind of obsessed with good sounding SS preamps, so I might try and recreate it (minus the reverb driver and recovery)