Magnavox Color Roundie

[Electronic M]

What is the HO tube grid voltage relative to specification? If it is not as negative as it should be by a decent margin then your H osc. is dead or not functioning correctly. I'd order a new osc. tube if the old one is weak. Sometimes a weak tube will work as an osc., but it is at high risk of sudden random failure and when the osc. fails if let run too long damage to the HO tube and or fly usually result.