I had something similar this week. Sick TSL100 with 2 tubes hotspotting -One side of bias 90mV...OK and the other reading 15V (!)..Turned out that R6 ( the 1 Ohm) was toasted.
I'm still struggling to get the bias right though - I'm getting 140mV on the side that was damaged and the adjustment is flat out ..which is way too hot..still looking for the cause... -38V pin 5 on V7&8 but only -30V on V5&6 with a pin 3 of 450V.
Anyone any ideas as to why the 1 Ohm should get toasted???.. what the other consequences may be??
any similar measurements you could make on a TSL100 would be helpful.

Cheers

Amp.