1965 Zenith Chassis 25MC36Z

[Palinurus]

I bought a 1965 Zenith color TV console yesterday, model 8642-6 and chassis 25MC36Z. I really haven't looked over the tubes closely, but the more immediate problem is that the filaments in the neck of the CRT aren't lighting up. The audio works fine, and when I attached a Sencore CR161 to the CRT the emissions show weak for the red gun, but strong for the green and blue. The filaments light up when the tester is attached. I plan to try to get a hold of the schematic for the set, but was wondering whether anyone might have some idea what would cause the problem. Would a bad tube impede power to the CRT? I did reach back and touched something I shouldn't have and got quite a jolt, so I think the high voltage is working okay.