[Radioroslyn]

If you want to do a quick test on the tubes pull out the 80 tube. Plug the set in and snap it on. Look at the tops of the tubes and you should see a small orange glow if the heater is OK. Do not do this with the 80 installed. You can damage the set if you haven't replaced the caps in it. As for the 80 tube use an ohm meter across the two fat pins on the bottom of the tube. Should show a very low resistance across these two pins. If not tube is bad.
GL
Terry