Picture Tube Brightener
 

Does anyone know how these things work? How do they make it brighter?

http://www.ebay.com/itm/Vintage-CBC-...item1c3bc66c61

These do not increase brightness of a good tube. They contain a transformer that raises the filament voltage. That increases the cathode temperature, temporarily increasing the electron emission of a worn tube with weak emission. They also make the cathodes wear out faster, so they are definitely a temporary fix for an old tube that is near the end of its life.

Ah! Now I know. Thank you! :yes:

I got a ton of them if anyone is interested.

I limped along with a couple of sets for a few years with them. New CRT's sure make you realize what you were missing.