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LCD screen backlight works for 2 seconds only... what would cause that? Answered

I have a ProView LCD screen that has it's backlight on for 2 seconds only, then it stops lighting.
The LCD panel itself still works, but with no backlight.
I opened the screen and I can't see anything burnt.
Every time I switch the screen on, all 4 CCFLs light up just fine, but only for 2 seconds, then they turn off again.  What would cause this?  Should I bother with trying to fix it, or is it too much of a hassle?



Best Answer 6 years ago

look at the driver circuit for burnt out capacitors - they will look bulged or popped, potentially with goo coming out.

If you have those, its an easy fix to solder new equivalent ones on.

As I said, I couldn't see any burnt components, that includes the capacitors...
In any case, how would a dead capacitor make the light turn on and then off again? I would think it wouldn't go on at all...?
Also, is there a way to check the capacitors with a multimeter (The one I have doesn't have a capacitance check)?

if they'd failed you'd know, bulding on the end caps/splits in the cap (its scored to weaken it strategically so if those score lines are popped open you know it's toast).

Basically they are all intact and look fine, but as I understand electrolitic capacitors can also dry out, and stop working. Would they still "explode" in such a case?

In any case, It seems that the caps are not to be blamed... I figure it's something else, since there 4 2 couples of 2 CCFLs, and each couple has it's own high voltage circuit. If it was a blown capacitor I suppose it would affect only 1 couple.

Can anyone think of anything else that would cause that? Should I just buy a LED strip to fit in there instead of the CCFLs?

led strip would work -- I can't think of much else that would die after 2 seconds. If its not the hv strips because they have individual drivers, perhaps the power circuit for the entire monitor.

ok i figured what was going on, capacitors and everything was ight only one wire from cold cathode or cfl or what is it was just from the connector little bit thin, i pulled an isolation tape over there and voilaa, monitor works again. also it is lot cooler both ways without the casing, glad i got the stand under it.

haha, i have the same trouble with some older lcd samsung monitor. at first backlights shut down, then i powwered from button off and on again and immediately pressed the button that you can choose light colours and it worked some time. now it shuts down and i can hear some sound as it goes off after 2 seconds. the i removed the casing of the monitor and it works, but as i put the case back around it mafaka shuts backlights again :S