Hi Chris,
Overwhelmed by replies, I see. I don't suspect the STRS, these either work or become inert, or blow their face off. STRS6707/8 will sub for these. Is the line stage working, eg., do you have CRT filaments or 200V up to the CRT board. IF so, try advancing the screen pot, you may have vertical collapse.
The possibilities are endless, but the brain has faded on these dinosaurs. Bruce.