the death of a fluorescent lamp vol. II (it gets scary)

For people wondering, fluorescent tubes indeed are in a vacuum. They are, in other words, a low-pressure mercury lamp , like those germicidal ones they sell to disinfect water but with a phosphor coating to make visible and unharmful light. You can find more info here: https://www.youtube.com/watch?v=AES_04auUBU

I don't know either but it's a cool effect. Just recently I've witnessed a fluorescent light have a break down at school. First few days it was the swirling next few days after one was dimly swirling and the rest of it was inactive, the rest of the time it was dead

Looks like an electronic ballast I have collected fluorescent lightbulbs for over 54 years and I’m not stopping now. I’m glad you got your fixed or fixed but you have an electronic ballast that’s what you have.

In my school, the fluorescent lamp near my table on the ceiling went bad last Wednesday. There was a purple glow at the right end [the ballast was in cold cathode mode I think], and you could barely see a filament arc. Every now and then the bulb would start flashing crazy and turn off for about 4-5 seconds, when I came back from playtime/recess the bulb was dead. Well at least I witnessed the last moments of it's life. When you turn the lights on it flickers a bit but it is a dim flicker. The ballast then goes into failure mode.

This happens when the thermionic coating on the filament in the bad end is fully depleted, resulting in the filament glowing bright orange, but at the same time unable to emit electrons efficiently, becoming the point of highest resistance inside the tube, with the increased voltage drop accross it inducing a harder ion bombardment onto the filament.

Back in 2010, I had an FC9T9 burn out in a similar fashion. End was purple then reddish and it did the swirly thing too. This is why I love fluorescent bulbs. They’re so cool that way.

I have seen this sort of failure before, and it's common for the instant start 8 footers, aka F96T12, operating off the old school magnetic ballast. The lamp begins to spiral and flicker wildly, one end gets very black with a red- orange glow. This occurs when the emission coating on one cathode is completely exhausted and can no longer emit electrons at the designated tube operating voltage, however the ballast open circuit voltage is so high that it will strike the tube anyway, and will continue until the lead wires inside the tube are completely burned away, the glass melts or cracks at the end wrecking the discharge, or the socket melts and the tube falls out. This can be especially serious for the newer T8 tubes, although these tend to be operating off electronic ballasts, which almost always has an EOL lamp detection system, which will shut the ballast down when it senses this happening. A magnetic ballast doesn't have this feature, but sometimes causes the ballast to burn out, although the old magnetic types tend to be very rugged and can take more abuse than the newer electronic versions. A rapid start lamp EOL depends on whether its a magnetic or electronic ballast, but tends to flicker for a while until it can no longer light. A preheat lamp EOL flashes on and off, as the starter will endlessly restrike, until the starter fails or the ballasts fails.

They certainly put on a show when they go out. I've seen some go black, blue, even red sometimes. And the "waves" running through the tube and the strobe effect although that isn't very good for the eyes. Very good job getting it fixed👍

The swirling is the starting arc in the cold cathode mode jumping to different places, like corona discharge goes to different places. [And HV X-rays.]

this is why I prefer magnetic ballasts

Wow. It should have a porcelain base, imagine if the tube falls due to melting plastic base

Very lucky to film the tube at end of life, interesting to see how it failed, the cathode was in distress at the end. Cool video!

I forced such situation on a T9 once, it started cycling and I removed the starter, forcing it to remain on, the flicker was HORRIBLE, but it went out with a burnout leaving a black mark on the fixture, I guess I damaged the ballast somehow, it hasn't even been a week since I replaced the lamp and it is starting to develop a grey ring, I ordered an electronic one to get rid of that puny horrible flickering caveman one (I was told to replace the entire thing with an LED one but meh, is not my house so I dont invest too much)

Look mate, I’m not trying to be mean but it’s partly your fault that the bulb connector/base thing melted as you should have replaced the tube when that orange/purple glow started, so next time when it begins to overheat and fail don’t let it, just take the tube out and replace it

Glad your back!

We are missing those flourocent tubes and CFLs is led era.

The fluorescent looks sooo good

It is very cool to see that and I been fascinated with it and I know I saw it in Kmart one evening and it was very cool to see it burning out!!!!

Pretty good job to capture it on Camera while the tube lamp is reaching its Eol, I still have my two of my 2ft T8 magnetic ballast fixture still working good, they last way super longer than leds in my opinion or a fact lol, I love Fluorescent lamps because they fail in many different ways :)

scary how hot that can get!