Zenith 17z22q odd scanning

[ha1156w]

Okay, I finally rounded up some tubes for my long-neglected Zenith 17Z22Q SC200 console. Brought it up slowly on the Variac and got the oddest result. I'd say it had vertical or horizontal collapse, but the line is static DIAGONAL! The yoke doesn't look disturbed. Yeah, it's complete recap time.....I relent. No audio (so no IF) and changing the channel doesn't create any difference whatsoever in the pattern so obviously no RF either. Anybody run across something this bizarre?