TV problems

Gotta TV problem

Yesterday my youngest borrowed my pick-up, telling me he had to have it right that minute. Fifteen minutes later he came back home with a HUGE projection TV in the truck. It is a Hitachi 60" diagonal HD projection TV. According to the internet it was originally offered in 1999. That sucker weighs at least 200 pounds. It took him and a muscle-bound friend to get it into the truck.
When he saw it he knocked on the front door and asked the owner why it was out at the street for the garbage people. The owner told him the sound didn't work. That seemed like a bit of a cop-out to me. The owner even thru in the remote!
When we got it home, we didn't even offload it from the truck. Ran an extension cord to the TV power supply and ran a cable extension to it. It powered up just great, and the cable input showed us a great picture. And the sound was just the way it was supposed to be. (So he lied about the sound).
So we muscled it into the house and hooked it up. It worked like a charm for about 60-90 seconds. Then the color divergence seemed to go to ca-ca. The blue-green tint seemed to be nearly 1/2 inch higher than the red tint. In other words, we had a double picture. Everything we saw on the screen was repeated on the screen, but was 1/2 inch higher on the screen, and was of a different tint.
Funny thing is that this model has a few vacuum tubes in the backside. My kid decided to to put a fan back there blowing cool air into the guts of the thing. He didn't even take the back panel off. (The back panel has a lot of 1/2 inch holes in it to facilitate internal cooling.) So far, after watching it for an hour, it is purring along as if it was fresh off the showroom floor.
They tell me that if it ain't broke, don't fix it. And I can't complain too much. But I was kinda wondering, Clearly, Hitachi didn't really design a TV that would go to sh_t because of heat problems. So why do I see these problems? Are the vacuum tubes the real culprit? Should I just shut my mouth and enjoy my good fortune?