Unofficial Austrumi Linux for English users forum golf & dvd

A Latvian and english Linux tiny operating system. used by golf & dvd lovers

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#1 2012-01-22 21:58:26

atang1
Administrator
Registered: 2006-03-30
Posts: 2705

Older laptop have cold cathode CCFL lamps that failed ? Inverter ?

The lamps may be damaged by human fingers touching the quartz tube. The sodium on the hand will change the quartz to sodium silicate and cause gas leakage. The lamp may turn white light to a pink hue.

When you replace lamps always use cotton or plastic gloves.

THE PINK HUE MAY ALSO BE THE RESULT OF A WEAL INVERTER. Some time using the inverter for a while and the electrolytic capacitors cured and lamps work normally afterwards.

If the lamps flicker and quit, it is the cause of gas in the lamp leaked, or the electrodes in the lamp deposited on the tube. The lamp has definitely to be replaced of old age.

Can you extend the life of a ccfl longer by turning it down or use darker? In theory, yes; the florescence pigments will last longer. But the electrodes deposit on the tube will stop the lamp from working properly(flickering).

The backlight lamps for LCD laptops are about $5 each on ebay. The inverter(12vdc to 220vac) about $10.

ccfl usually last 10,000 hours continuously or 5 years. Today, 10 year old laptops are generally still using the same ccfl lamps, due to the fact that laptops may have been left unused for a log time. Dried up electrolytic capacitors are more troublesome, causing a pink screen on boot up.

So, the idea of replacing the entire used LCD assembly in its cover if $20 at ebay is more attractive in terms of labor savings.

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2012-01-22 21:58:26

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#2 2012-05-18 08:49:37

atang1
Administrator
Registered: 2006-03-30
Posts: 2705

Re: Older laptop have cold cathode CCFL lamps that failed ? Inverter ?

CCFL problems could be just contact resistance problem?

Pressing on the edge of the top cover sometimes make ccfl brighter?

Contact resistance is cause by tin lead oxide. It is repaired by boundary lubricant such as petroleum jelly on the surface to prevent oxidation.

You have to remove the top cover to remove the ccfl and apply petroleum jelly to the electrical contacts to the ccfl tube.

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#3 2012-05-29 18:26:00

atang1
Administrator
Registered: 2006-03-30
Posts: 2705

Re: Older laptop have cold cathode CCFL lamps that failed ? Inverter ?

CCFL starts pink and warm up to white?

This is the characteristics of ccfl lamps. It has to do with current drawn to excite the phosphos.
Just use it and it may improve.

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#4 2012-09-15 09:48:40

atang1
Administrator
Registered: 2006-03-30
Posts: 2705

Re: Older laptop have cold cathode CCFL lamps that failed ? Inverter ?

Pink ccfl lights when you tart the laptop9old) means the capacitor on the inverter is dried up. Not able to supply enough current.

When you leave it on for a while, the capacitor cured, and the light is white again. Frequent use cured the capacitor in the inverter. No need to fix it.

Often, digital TV has pink backlight when you turn it on. Then after a few minutes it shut off by itself. the capacitor dried up was never cured. And you need to replace the ccfl tubes. This maybe due to circuit(capacitor dried up) of the 12 volt power supply, which supplies the power to the ccfl inverter. The tubes were too old(used over 10,000 hours), must be replaced.

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#5 2013-09-29 08:11:04

atang1
Administrator
Registered: 2006-03-30
Posts: 2705

Re: Older laptop have cold cathode CCFL lamps that failed ? Inverter ?

Inverter chip may overheat if absorbed moisture. Then screen may dim. If you keep using the laptop, drive out the moisture from the inverter chip, the ccfl will keep lighting up. You can fix your problem just keep on using this laptop.

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