Why is the CRT taking longer to light up?

[Phil Nelson]

I have learned to clean the tube pins (and test tubes) first, before attempting any service. As Tubejunke points out, that can save embarrassing head-scratching later on.

http://antiqueradio.org/FirstStepsInRestoration.htm

Tube pins aren't so delicate that you need to fear cleaning them. I have brightened up many, many of them using fine sandpaper or a scraper, with no problem.

Phil Nelson
Phil's Old Radios
htt[://antiqueradio.org/index.html

[Magnavox300]

Thanks, I will clean all the pins thoroughly, I am sure they need it!

[Tubejunke]

Originally Posted by Magnavox300

I remember once reading you shouldn't scratch the tube pins, since they are coated? I would rather go with your suggestion, and get them bright again and not worry about it, I'd rather have a good connection...
You said use a pocket knife or something and scrape them till they shine,
are you sure that's okay to do?

I think my reply is a little late in the game and you have probably already done the right thing. Actually, I found it interesting that you stated that you read that the tube pins were somehow coated. I'm not saying that there is no truth to that; maybe some special applications or something, but I have never heard of any coating. If they did coat them with say some conductive anti-oxidant or something, then it didn't work. Gold would be the way to go, but counter cost effective. Silver is the best conductor, but it tarnishes which would give us what we have. The pocket knife (cheap) or whatever implement you use to me is one of your most valuable service tools; right up there with your V,O.M.

Also, I think the topic of pins being delicate came up and someone correctly put any fears there at ease. In fact, they are very rugged in my experience. Even the small pins on say a seven pin miniature can be bent and straightened a number of times without issue. Actually, I have never broken one. The most likely to break would be something like an octal, and they would break from the plastic base. C.R.T. pins have a bad habit of needing to be re-soldering once the epoxy (or whatever glue they used) gives out and the plug is left supported by the wires protruding from the glass.

[walterbeers]

Don't know if this relates to your set, however, sometimes crts develop an intermittent open cathode, where the picture blacks out, and if you tap the neck of the tube lines of the raster will flash intermittently with the tapping and sometime it cures the problem for a while. Only real cure is to replace the crt. Just don't hit the next of the tube too hard. In color crts the same thing can happen, only usually just one color is involved, R. B or G

[old_coot88]

Originally Posted by walterbeers

...In color crts the same thing can happen, only usually just one color is involved, R. B or G

I never saw a case of intermittent cathode in a color CRT (not saying it hasn't happened, though). But saw oodles of heater-cathode shorts that show up intermittently when tapping the neck. (H-K shorts kill the luma while leaving the chroma intact, since chroma goes in on the grids.)