Any Information on My RCA 21-S-510

[Hcompton79]

I picked up this TV today it used to belong to my great grandmother, Its an RCA Victor Model 21-S-510N. It uses a 21 inch picture tube. I am wondering what I should expect when restoring this, as it will be my first TV restoration although I have done a few radios. Any gotchas or unobtanium parts? Also what kind of picture tube is this and is there a replacement out there if bad?

http://www.videokarma.org/attachment...1&d=1453140133

I brought it up on a dim bulb tester and all seemed fine, although I did have to find a 250 watt bulb as the power requirements are large for a set like this. I was disappointed as the picture tube did not light up at first but after leaving it on for about 10 minutes the picture tube became bright enough to watch in average room lighting, I got a raster and sound from my transmitter but I did not get a picture. Also there was a picture tube brightener on the CRT which may not be a good sign.