The drive control is set to the point where I'm getting just -68V to the HO tube, its maximum position, and the instructions noted to turn the slug on the tuning coil to the point where the (current) meter is at its lowest reading. All related resistors have been checked and all caps replaced. Is it possible that the circuit's running 'wide open' without having the CRT hooked up, and that's causing the red plate? I can restore the slug to its former position or approximate, but I'm concerned about danger to the flyback. Would monitoring the cathode current of the HO be about the only choice I'd have to prevent such a catastrophe?

Thanks,
Michael