crt red gun
 

hey guys, i picked up another combo like mine the other day. it has raster, cleaned the contacts on the neck of the tube and the socket but am getting intermittent red gun activity, any suggestions on what to do? when i first turn it on the red will work but putts out after a few minutes. its a 21fjp22 original tube in the set thats been sitting in a basement for 27 years. i guess this is how all the projects get started. thanks Bruce

Intermittent cathode? Re-solder the pins and if that doesn't work, try a CRT tester with the 'weld cathode' function, maybe?

before assuming the CRT is the issue, you should prob check to make sure everthing else is ok. I would start by monitoring the voltages at the CRT pins on the red gun and see what happens when it goes away. I am assuming the filament is staying lit.

after that I would put a scope on the pins that control the signal, again watching to see what happens. Or just hook it up to a known working chassis if you have one.

What chassis does it have? I just learned that the CTC 15s, 16s and their clones had a lot of intermittent connections on the chroma board. I have a set with the red doing what yours is doing and mine's a 15 clone.
You could also hook up a CRT tester and leave it on red for a while, gently tapping the neck to see if there are any fluctuations in the emission or if the filament flickers.

crt red gun
 

its a ctc16, when i tap on the neck it flickers, im going to see if the connections are good in the socket, i already sprayed some cleaner in but ill give it another try. im hoping the tube is good, i can do a cataract repair and it should be up and running.

crt red gun
 

by the way, all the guns are lit in the neck

Hope it's an external intermittent and all you need is to solder the pin.

Q, are the filaments tied together internally or do they have indivdual leads, I ask since I have a roundie with a un lit filament. I may have asked aready, jus cant recall

Wired internally, parallel of course. I lost a blue gun filament in a pristine RCA Hi-Lite 21FJP22...that one hurt but at the time I traded it's dud for a rebuilt. Wish I still had that one going instead even after all these years.