Do CRT tubes just "die"...?

SilverDuck

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I had a machine on location with a 25" U-5000 monitor that quit. I sent the chassis off the get redone, and got it back, and still nothing. Getting no neck glow, but I do get that nice "Fizzle" when the game comes on. I was not there when the machine died, so I cannot attest to how or what happened. Since we know the chassis is good, can I assume the tube is dead? The tube isn't cracked or broken. Do they just "die"?
 
Very, very, very rarely. If the filament burns out, then the tube will be completely dead. This almost never happens on modern tubes. In all the monitors and televisions I've worked on, I have never once seen an open filament on a modern tube (that wasn't also cracked) - and even old old tubes only once or twice (40's and 50's era stuff).

It's easy enough to check too - just use your meter to check for resistance on the heater pins. If it's open, then the filament burned out. Otherwise, I think it's more likely to be something wrong with the monitor chassis.

-Ian
 
Just a thought, you did remember to turn up the SCREEN control on the flyback, right? It's easy to get bumped during shipping or installation. Or, if this monitor has an adjustment board, it's connected properly, and you've tried it's brightness control?

Not every tube will have an obviously visible filament glow - it's a very dull orange glow, and it's up inside the gun assembly, so you can't always see it. Turn out all the lights and see if you can see it glowing.

-Ian
 
Just a thought, you did remember to turn up the SCREEN control on the flyback, right? It's easy to get bumped during shipping or installation. Or, if this monitor has an adjustment board, it's connected properly, and you've tried it's brightness control?

Not every tube will have an obviously visible filament glow - it's a very dull orange glow, and it's up inside the gun assembly, so you can't always see it. Turn out all the lights and see if you can see it glowing.

-Ian

But that would not have caused the monitor to die in the first place. Whatever happened to the game....is still there. The chassis was just repaired by a very reputable member here, so I trust that it works. Whatever the original problem was....still is.
 
The bottom "key" pin on the neck of the tube came out of the tube. The little needle pin that is inside the key part of the neck....came out.

Is the tube officially junk?
 
Shooting a Microwave beam at a tube will fry a tube if it's is strong enough. It does bring the local FCC guy to come for a visit. That when you find out the contractor for the RF shielding didn't have a clue how to install shielding.
 
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