Is it the inverter, or the LCD screen or something else?


Sep 13, 2012

OK, this is the situation for my Compaq Presario R3000:

1) Few weeks ago the screen became dark (with a flashlight I could still see things). Pressing the lid button multiple times ignited the screen back on for a while.
2) New inverter placed and didnt work.
3) Old inverter still works for a couple of seconds and then have to press the lid button again multiple times to keep igniting the screen light.
4) Then tried another new inverter and screen cracked on me (could be because of old age or the new inverter???). I read that a new inverter could generate so much voltage that an already damaged (weak) CCFL light gets permanently broken. I did hear some crackling electricity sounds in my screen with the new inverter trying to power up my screen light. Also I pressed the lid button multiple times again and nothing happened anymore (I read that a new inverter can actually shut down if it has no success lighting up the screen, so its like a precaution measure taken by the inverter because the CCFL bulb is broken, right?).
5) I did notice that if I play a bit with how I let the inverter hang and move it a bit, that the screen light pops on a few seconds again. That was a few days ago, but that trick doesnt work anymore. However, the keypad light does pop on if I press the lid button multiple times! So this means that my mobo generates enough power to the inverter and the mobo overall is fine, right?
6) I connected an external monitor and all is well, I can see and do everything with my laptop. So I guess it means the mobo is fine, the video card, video graphics and HDD also all fully functional. Just on my cracked laptop screen do I have to use a flashlight to see something.

I hope you guys can help me diagnose the problem because I am dreaded about exchanging the screen entirely for USD 200.00 (unless it works ofcourse).

My questions for above description of events:
1) Would a new screen solve my problem?
2) I checked the video cable and connections and nothing seems wrong. Could this still have something to do with it? How will I know?
3) Does my mobo video controller tell my inverter to turn on (or do I have a problem with burned capacitators or fuses)?
4) Can a (bad or wrong) inverter actually damage / break my screen (or new screen)? So, do inverter and screen need to be compatible somehow?

I much appreciate the time you have taken to read this lenghty problem and the time you take to help me out to solve this challenge. Thanks a lot.


Jul 5, 2012
Backlight issues are most often fixed by replacing the display panel, but it can also be a bad video cable or even bad video chip. Those are far less likely possibilities, but I have run into it. When I worked as a hardware tech, I kept several spare cables around to test with.

Given, assuming I'm reading things correctly, the current LCD panel is already broken/cracked, you obviously need to replace it. So you may as well get a new video cable with it. The relative cost to the LCD panel is likely going to be trivial, so if you ultimately don't need it, no big expense and it's a relatively small piece if you're like me and hoard cables.


Sep 13, 2012

I took the advise and changed the LCD screen and it worked. It seemed the crackling buzzing humming sound on my screen was due to bad electrical connections between the inverter and the CCFL, it looked and smelled totally burned through as well. The old video cable proved well OK, so didnt change that. Nothing wrong with HDD or motherboard as I tested this before on an external monitor.

Thanks all for your help.
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