Let me repeat David's friendly advice that you should replace the old capacitors (especially electrolytics) before expecting the TV to play without the risk of damaging itself. These articles give you an idea what's generally involved in getting old TVs to work.
http://www.antiqueradio.org/RCAT-100Television.htm
http://www.antiqueradio.org/DuMontRA-103Television.htm
In the first article, note the section about replacing capacitors. This article has more info on that topic.
http://www.antiqueradio.org/recap.htm
If you do it right, you may be able to make your old TV play well and give you enjoyment for a long time. You usually can't expect to reach that point just by replacing a couple of tubes and blowing off the dust. It's more like finding a 50-year old car in a barn. You wouldn't expect to just top off the gas tank and speed away on a long trip.
If you have never done anything like soldering, I'd recommend buying a cheap old tube radio at a thrift store and practicing on that first. TVs are not good beginner projects. (Among other things, the high voltage can kill you.)
Phil Nelson