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Mini cold cathode tube from a notebook display

Mini cold cathode tube from a notebook display

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This came from a defective Acer notebook. The ballast was also easy to extract and it worked well.

osram_t12_20w_halo2.jpg osram_t12_20w_halo1.jpg PIC00007.JPG 2012-03-08_17_46_51.jpg

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Filename:PIC00007.JPG
Album name:Prismatic / Fluorescent-tube collection
Keywords:Miscellaneous
File Size:702 KB
Date added:Oct 21, 2012
Dimensions:2048 x 1536 pixels
Displayed:215 times
Date Time:2003:03:18 21:19:28
DateTime Original:2003:03:18 21:19:28
Exposure Bias:0 EV
Exposure Time:1/30 sec
FNumber:f 2.8
Flash:No Flash
Focal length:14.8 mm
ISO:200
Make:OLYMPUS OPTICAL CO.,LTD
Model:C3000Z
Software:v353p-75
URL:https://www.lighting-gallery.net/gallery/displayimage.php?pos=-71444
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dor123
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Oct 21, 2012 at 03:34 PM Author: dor123
Never seen hot cathode fluorescent lamps in LCD backlighting. Only cold cathode.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

Prismatic
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Oct 21, 2012 at 03:45 PM Author: Prismatic
Oops. You're correct - I have changed it

Prismatic@YouTube:

http://www.youtube.com/slprismatic

Alights
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USA (120V 60HZ)


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Oct 21, 2012 at 10:46 PM Author: Alights
cool! But is it EOL? Looks as if one end is orange
Prismatic
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Oct 22, 2012 at 01:03 AM Author: Prismatic
Hmmm. I don't know. Maybe I put too much voltage on the ballast. I can't find it anymore (the picture is from 2003)

Prismatic@YouTube:

http://www.youtube.com/slprismatic

Xytrell
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Oct 22, 2012 at 01:30 AM Author: Xytrell
They're current regulated. They will supply the same lamp current from something like 8V all the way up to 15V or more.
dor123
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Oct 22, 2012 at 05:46 AM Author: dor123
We have an HP scanner that the ends of its CCFL, glowed orangish red. Initially I thought that this is because of the heated electrodes. Today I know that these were neon negative glows that formed around the electrodes, as a result of a neon-argon buffering.
I think that this is the same situation here.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

Xytrell
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Oct 22, 2012 at 12:12 PM Author: Xytrell
Am I the only one that doesn't see pink in the picture?
BG101
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EYE H80 Mercury Vapour


Brian TheTellyman
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Oct 25, 2012 at 11:43 AM Author: BG101
I can't see it either .. these LCD monitors don't help!


BG

Say NO to DICTATORSHIP in the form of bulb/tube/ballast bans !!

Ash
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Oct 25, 2012 at 11:54 AM Author: Ash
Those lamps sometimes go pink, sometimes go flickering (random flicker - not rectification) and usually heat up a lot (up to glow) in the end before they EOL

Having replaced quite a lot of them in different screens, they often crack from the heat at the EOL end, and sometimes get hot enough to burn the isolation on the wiring going along the back of the reflector. And to melt into the silicone parts in the ends... Sometimes they just tear in pieces when i try to extract the EOL lamp that melted to them - Then i substitute them with plain heat shrink

The ballasts have sense for missing or not working lamps - If you trace the cold side wire of the lamp (the thinner one) you'll see that it goes by the transformer and into the electronics. There it goes to a current sense so that the ballast shuts down if there is no current through the lamp. Since lamps approaching EOL have less stable discharge sometimes the ballast will kick into this EOL protection mode and require to switch the monitor off and on (flip the screen down and up) to restart it - This is a sign of aging lamps that are soon to EOL (however in many monitors its all just bad capacitors)
FrontSideBus
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Oct 25, 2012 at 12:46 PM Author: FrontSideBus
I was playing with one of these a while ago and I got a cracking belter off it!
I mainly strip old laptops for the magnesium frames that are great fun to throw on bonfires

UK out of the EU!
http://www.lighting-gallery.net/gallery/index.php?cat=11271

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Oct 25, 2012 at 01:22 PM Author: Medved
@Xytrell "They're current regulated. They will supply the same lamp current from something like 8V all the way up to 15V or more.":
The simple ones, based on the simple Royer oscillator (so the transformer have at least 5 pins on the low voltage side and there is quite large extra inductor on the board) feed the tube with the current roughly proportional to the input voltages. So too high input voltage would mean lamp overpower. But in order to overpower the lamp so it would be dangerous for it, would require more than double the rated input voltage, what would immediately destroy the inverter...
The stabilized ones use H-bridge output stage on the LV side, so suffice with 2..3pins there and no extra choke (they utilize the transformer's leakage inductance for the ballasting purpose) and yes, these usually regulate the lamp power regardless on the battery voltage.

No more selfballasted c***

dor123
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Oct 25, 2012 at 01:24 PM Author: dor123
Ash: A red glow at the end of these lamps, are usually as a result of neon-argon penning mixture. Electrodes of CCFL, can't heat so much that they would incandescence. This can be occured only in hot cathode lamps.
In a Mustek scanner that I have seen in the far past, in the CPA office of my father, I've seen that its CCFL, turned red. Probably because of mercury starvation and having a neon-argon penning mixture as a buffer gas.
In an HP Scanjet which we had in my mother home in the far past, I have seen that its CCFL ends glows red. Initially I thought that the electrodes glows to incandescence. Today I know that this was because of a neon-argon penning mixture.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

douro20
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Oct 25, 2012 at 01:30 PM Author: douro20
I used to do this quite a lot with old notebook computers with 12v CCFL backlights. To determine how to power it, I'd connect 5v across a couple of test leads and touch certain components on the input end of the board until the inverter powers up.
Ash
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Oct 25, 2012 at 02:40 PM Author: Ash
Or look at the datasheet of the chip thats in the inverter. Its all there. It is dimmable too

Those CCFLs dont emit any red glow when struck (even if struck for a moment with a piezo element). There is continuous red glow in EOL lamps however - and they indeed heat enough (esp at the EOL end) to crack the lamp, melt it to the silicone isolator, sometimes even melt the lamp glass a bit, and sometimes damage wiring in the assembly. So no wonder the electrode glows red....
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