Campaq Presario F700 screen backlight issues!

By Cinders
Aug 30, 2010
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  1. Okay. I have an older Compaq Presario F700 and when it's turned on the screen does not light up. The computer seems to stall at the BIOS hardware check. I have removed the memory and the motherboard complains at me because it can't find any memory. I have removed the hard drive and nothing changes. I have tried connecting the laptop to a known working CRT monitor with a D sub connector and still get zero video. I was at first thinking that the screen's back light may be burnt, but now that I found and tried the D sub connection I'm thinking there may be bigger problems. Unless somebody is gonna tell me the CRT will not display the motherboard POST messages then I'm thinking that the motherboard needs to be replaced, or the screen and its power inverter need to be replaced. I would appreciate any comments.
  2. ucould2

    ucould2 TechSpot Enthusiast Posts: 329

    I thought that if you hold a torch light up to the screen in the dark and the Backlight was broken you should still be able to navigate around or so I have found in in this corner of the woods?
  3. Cinders

    Cinders TechSpot Chancellor Topic Starter Posts: 1,313   +12

    Thank You. I tried using a flashlight to see deeper into the screen. There was no image at all.

    Does anybody know what voltage will be present at the ribbon cable from the video chip to the screen if the GPU is working?
  4. Cinders

    Cinders TechSpot Chancellor Topic Starter Posts: 1,313   +12

    I found out that FN+F4 will force the video to be displayed to the external video port and there was still no video, so the motherboard is probably bad.


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