I'm feeling much better actually.
Well I finally opened up the Zenith. I was going to make a list of the tubes and see if there were any leaking caps and such. I got the chassis out of the plastic bucket with no trouble. I counted 7 tubes 3 of which were zenith which looked quite old and 4 of which were Sylvania which are rather new. Kind of a bummer because the markings stating the type of tube are quite faint and unreadable. Hmmm.
I tried to get the bottom plate off to scope out the capacitors but the way the thing is setup I can't get my driver on the last two bolts. Hmmm.
Well I was then checking out the speaker when I noticed something jammed in between the basket and the cone. It was an 8" long, 1/2" inch wide strip of black velvet. They use it all around the face plate to make a nice seal when it's all closed up. Apparently when the last person was in the radio they pushed the face plate on and the velvet wound up jammed against the back of the cone. This was clearly causing some of my bad sound problem.
I freed the velvet and glued it to the top of the faceplate where it belongs. I bundled it all up and gave him another try. Wow! What a difference. It's funny because before the tone control had almost no effect at all. Now the sound is much more open and I can flatten it out or lower it with the tone control. Very happy!
This is one nice radio after all. Some day I'll figure out what tubes are in this thing and replace them all as well as the caps, for now it sure does sound nice.
Thanks for all the advice lads. I'll be back with this radio one day with some more questions.