Replaced laptop screen, now the displayed resolution is wrong but should not be

Question

I replaced a laptop screen in a Dell Vostro 1520. Both the old and new screens are 1440x900 resolution as confirmed by part numbers but new screen is glossy the old one is matt - with slightly different part numbers (B154PW02 old, B154PW01 new).

Now Windows 7 says the maximum resolution with the new screen is 1200x800. Can't be set higher to 1440x900. When Bios messages show at start up the resolution is clearly wrong with half the text off the screen.

What can be wrong?

[Edit: have now updated the bios to latest version and reinstalled video drivers. The replacement screen (model B154PW01) is a few years older than the broken screen B154PW02. The video software (intel) does not detect any supported resolutions above 1200x800 still.]

Answer 1

Always make sure you are using the latest display drivers, also check windows update to see if it can find new drivers for your actual LCD panel or if you can find an inf file for that panel by googling for it.

To me it sounds like the laptop is either not properly reading the EDID information from the new display or the LCD driver windows chose to install is not working with the new hardware.

If you can't find updated GPU drivers or panel inf files then you can try to manually override the display settings. I think that will only work once it gets to Windows and not solve the problem at POST. I see that the 1520 has 2 different GPU configurations, one with an Intel X4500MHD and one with an NVidia 9300M GS. If you are using the version with the NVidia GPU then you can probably override the detected resolutions with your own by going through the control panel and going to "Change Resolution" and hitting the Customize button. I am not sure if the Intel chipset offers that kind of support.

Answer 2

Try reinstalling the video driver. Or if there is an NVidia or ATI graphics chip in the laptop, try using the software for the chip.