[Hammarlund] cheap tubes...

[Mike Durff]

Todd said "...We need to keep in mind that tubes were cheap and plentiful then,everything used them. So if their life expectancy was cut by 25% or more,
so what? Swapping out tubes before failure as part of a PM plan was
commonplace. Many a ham has benefited from broadcast transmitter pulls."

I was taught in Radio & TV school ( 1965 ) to replace all the tubes first, then start troubleshooting if the problem didn't disappear.. Of course, the TV's that needed repair were from the 1950's and tubes were around a buck each. I think the "all american 5" radio set of tubes sold for $3.95 or something...

Wow, 50 years ago... I am old...