[Heathkit] SB-200 Problem

[Barockteer at aol.com]

Sounds like you're down to just one tube. When this happens, resonances are 
out of whack because of higher plate impedance, and load current is way low.

Are both tubes lit?

Do both tubes show signs of working, i.e. plate turns red or generates heat?

Other than that, look for problems in plate tank (band switch open) or 
possibly tuned input circuit...

73,

Tony, K1KP