Lenovo Thinkpad T420s CMOS Defaults

[feherhollo]

Hi,

I have Thinkpad T420s with discrete NVIDIA chip. The NVIDIA chip went faulty and I accidentaly switched the display to NVIDIA on the BIOS. Now laptop won't post. How can I set bios settings to default? Is there any clear cmos jumper or anything?

HELP!!

[exe557]

Re: Lenovo Thinkpad T420s CMOS Defaults

Remove the yellow cmos battery, all other batteries, push power button for 30 seconds. Reinstall all batteries and cmos data is cleared

[feherhollo]

Re: Lenovo Thinkpad T420s CMOS Defaults

Remove the yellow cmos battery, all other batteries, push power button for 30 seconds. Reinstall all batteries and cmos data is cleared

I have do that and nothing. Still the same. Laptop won't post because Nvidia chip selected as primary boot display device. The default settings is Intel.
No video on VGA also...
The laptop was post and tested before the settings changed. So the board fully worked...

[exe557]

Re: Lenovo Thinkpad T420s CMOS Defaults

You can try to enter BIOS blind and load setup default via F9 and F10

[feherhollo]

Re: Lenovo Thinkpad T420s CMOS Defaults

You can try to enter BIOS blind and load setup default via F9 and F10

Yes you were right but computer won't POST. So nothing just solid power led! Can't hear any beep or cannot enter the boot menu with Thinkvantage button. Thats why I ask some hardware method of clear CMOS because if settings back to factory state, my laptop will be alive again...

[feherhollo]

Re: Lenovo Thinkpad T420s CMOS Defaults

Is there somebody knows how to edit the bios dump and set primary video to integrated intel vga with optimus disabled if I upload my dump??