How can you tell your TV tube is dying?

TV tubes start dying from the day they're first made. It's generally a very slow process and if you watch the TV on a regular basis, you'll most likely not notice the changes from day to day. The other interesting fact is that usually TV tubes will out last the lifetime of the set as they generally develop other failures, requiring repair.

However, that's not to say that a TV tube can't go bad. Unless you're a trained television technician, it's difficult to tell exactly what's going on with a tube without looking at it. The tube may be fine, but the customer has gotten the controls set improperly, the tube may have become gassy' or just showing age wear, or some other internal problem in the TV is making the tube look bad.