VT-131 prints?

I have a VT-131 suffering from video circuit problems. The logic seems to be ok -- does a self test, led dance, emits a normal beep, and ends with the on-line led lit. The crt filament is glowing. Key click happens when keys are pressed. No screen display. I've turned up brightness in set-up, flying blind. Haven't twiddled the pot yet. So far, I've just taken the lid off, and am looking into the still-assembled chassis. The video board has some very charred-looking spots around the solder pads of one component (cap? spherical white ceramic-like device with two stout leads) down and to the right of the brightness adjustment. The tech manuals from bitsavers and vt100.net don't give me enough info to identify the component in question. Anyone have prints they'd be willing to scan bits of for me? Or read off to me by e-mail? Or have "replace this, kid" or "you're screwed" specific knowledge of this scenario? TIA, De