1949 Silvertone Model 139
 

I picked up a 1949 Silvertone TV yesterday. The CRT is a 12LP4 roundie which is very weak, though a picture does appear. I don't have the time to really delve into it, but the immediate problem I encountered is the vertical centering. The bottom half of the screen is blank. I don't see any control knob in the back to adjust it. I was wondering whether this might be a weak tube. I haven't gone through and tested the tubes yet.

Any comments would be greatly appreciated. Thanks.

Could be a tube, but it could be a capacitor if the set has not been re-capped.
Since the CRT is weak I might assume that it has not been restored (gone through, checked for bad components and certain types of capacitors replaced).
More background about it and you would be a nice thing for you to give.

Thanks for the information. I think I'll test out the vertical oscillator tube, then if that doesn't work some of the capacitors. The cabinet is very good condition. There is a hum in the audio, so I plan to change the electrolytic capacitors at the very least. I unplugged the CRT and hooked up a DVD player and was able to play an audiobook. In the meanwhile I'll keep an eye out for an inexpensive 12LP4 tube.

When inquiring about a particular set, always furnish the chassis number as well! Sears had so many suppliers, that one appears to be a rebadged Hallicrafters, full of those waxy, leaky capacitors. :thumbsdn:

If you are within driving distance (I won't ship) of Milwaukee I have a good spare 12LP4 I'd let go for $100...

There's one right now on eBay for $160 shipped