need help on a laptop LCD panel, "2 minutes to black"

[meanderer]

I am trying to repair a acer laptop with a dark panel. The panel first came as completely dark. I first suspect the inverter. Ordered one online and replaced it.

It lights up for about 5 minutes thru the windows boot screen. Then shuts off again. The inverter replacement improves the problem but doesn't fix it.

I tried to turn down the brightness a bit, the light starts to flicker then shuts off as well.

Should I try a different inverter? or should I try to replace the bulb, which is something I have little confidence in doing (and probably give up at that point)?

Another laptop in the past, I was able to keep the light up by lowering the brightness. I cannot do the same with this one. Is there any difference between the 2 cases?

[BShanahan14rulz]

Re: need help on a laptop LCD panel, "2 minutes to black"

I just want to add that replacing the bulb is probably easier than you are thinking.
I usually don't take the screens apart unless I'm harvesting some diffusion plastic or diffraction gratings, but of the two screens I have taken apart, the tubes are in a metal "reflector" thing, and the whole thing slides out one side of the backlight panel.

So if the experts here reply that you may need new tubes, don't chalk it up as a loss just yet. I'm not an expert, but it does sound like as something heats up, it fails or goes out of spec. New inverter board probably rules out a bad inverter board. If the laptop is pretty old, the tubes may be bad.

I've got a travelmate 42-something-or-other, that thing's got a huge screen but very dim. Quite honestly, I'm surprised that the tubes haven't shattered, the way I treat that poor thing!

[alexanna]

Re: need help on a laptop LCD panel, "2 minutes to black"

I am trying to repair a acer laptop with a dark panel. The panel first came as completely dark. I first suspect the inverter. Ordered one online and replaced it.

It lights up for about 5 minutes thru the windows boot screen. Then shuts off again. The inverter replacement improves the problem but doesn't fix it.

I tried to turn down the brightness a bit, the light starts to flicker then shuts off as well.

Should I try a different inverter? or should I try to replace the bulb, which is something I have little confidence in doing (and probably give up at that point)?

Another laptop in the past, I was able to keep the light up by lowering the brightness. I cannot do the same with this one. Is there any difference between the 2 cases?

Well you have replaced the inverter, so I would hope it's good.
On the low voltage side of the inverter.
Check if you have a power and a ground going to the inverter, and what are the voltages of the BL on signal, And the ADJ dim voltage, When the back light is on. Do any of these voltages change when the back light goes off? You are trying to identify 3 pins with a voltage and one pin that has a ground.
This should give you an idea of what to look for http://www.lcdparts.net/howto/U_PIN.aspx
Al

[meanderer]

Re: need help on a laptop LCD panel, "2 minutes to black"

thanks for the help, turns out that these so called "new" inverters are not made to spec and turns off after 2 minutes. I ordered one USED and it works perfectly fine for at least 2 hours...

Since I have been ordering inverters from the same vendor. This vendor's bad inverter record is currently 100%.

and also the chance of a used inverter to work is at 100% as well.

What should I get in the same situation I wonder :P