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

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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?
Thanks!

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frollard

Best Answer 8 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.

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Morgantaofrollard

Answer 8 years ago

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)?
Thanks

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frollardMorgantao

Answer 8 years ago

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).

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Morgantaofrollard

Answer 8 years ago

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?

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frollardMorgantao

Answer 8 years ago

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.

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kaamel21

6 years ago

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.

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kaamel21

6 years ago

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