Lenovo b5400 black screen at desktop ... long story

compufreek

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Sep 17, 2014
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So...
I have recived a friends laptop to format and install new windows. Had to install new bios for the laptop as it had updated uefi bios. Bios install crashed and i ended up with bricked laptop with no way to recover. I bought a programmer from china and desoldered the bios chip with software from some random dude in forums. I put everything back together and the laptop boots up. It gets to windows 8.1 loading screen and when it should show up the dsktop i get a black screen with strange flicker* pc is running normally just the screen is black. I try everything i can but nothing helps so i decide to just reinstall the OS. After the instalation i get to desktop no problem and start to update windows ... as the nvidia driver install aggain i get black screen. so my first tought was when i desoldered the bios i managed to damage the nvidia chip. I reboot to safe mode and delete the driver and go into bios and disable switchable graphic and i boot back into windows ... after 5 minutes ... black screen aggain .... so i reinstall os and see that when the windows generic driver is in place the PC runs normally the very second i install intel or nvidia driver i get black screen tried to connect hdmi and it doesnt work then i tried an older screen with VGA cable and that WORKS! i run a few tests and i can run fur mark on the nvidia or intel and both runs just fine. So my conclusion is that digital ports are screved, analog works just fine ... but its strange as the monitor (at least i think its always in digital mode) runs ok with windows generic driver but not on analog. anny idea?

-is it possible that it is a bios issue ? (i have updated the bios from official site to 2.08 after i reprogrammed the chip)
-did i burn the digital output controller?
-should i try to bake the motherboard (reflow the solder on entire board 180degres/8minutes)
-if it is broken is there a way to make the lcd use the analog signal to display image so that the laptop would be usable aggain?


sorry for really long post, hope annyone will take the time to read it.

cheers !!
 

viveknayyar007

Honorable
Apr 25, 2013
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Hello compufreek

There are good chances that desoldering, reprogramming, and re-soldering the BIOS may have caused some problem with the chip.

About the screen being digital, it is likely that only the ports present to connect the external digital peripherals have become faulty and the internal connections are still intact.

About the BIOS issue - As long as you are able to update the BIOS successfully and you are experiencing no issues while running the computer, it is unlikely that there is any BIOS issue.

About baking the motherboard - If you are able to use your computer without any issues, I would recommend to continue using it as long as possible. You should think of any solution that involves your intervention with the hardware only when everything stops working and you are sure that the problem is not related to any software or the installed operating system itself.

About the broken LCD or laptop - You can always replace the faulty parts of your laptop and if needed, even the motherboard can be replaced altogether to bring your laptop back to life. You can get all the required information about the parts of your laptop from the guide available here.

Bottom Line
Since the complexities (if any) generated in the BIOS chip and/or motherboard due to desoldering and resoldering cannot be undone, you may want to use the laptop for as long as possible and go for troubleshooting and repairing only when the computer is dead. When this happens, you may also want to take your laptop to a Lenovo's authorized service center and let the certified professionals do the job for you. :)

Hope this helps.
 

viveknayyar007

Honorable
Apr 25, 2013
1,003
0
12,210
133
Hello compufreek

There are good chances that desoldering, reprogramming, and re-soldering the BIOS may have caused some problem with the chip.

About the screen being digital, it is likely that only the ports present to connect the external digital peripherals have become faulty and the internal connections are still intact.

About the BIOS issue - As long as you are able to update the BIOS successfully and you are experiencing no issues while running the computer, it is unlikely that there is any BIOS issue.

About baking the motherboard - If you are able to use your computer without any issues, I would recommend to continue using it as long as possible. You should think of any solution that involves your intervention with the hardware only when everything stops working and you are sure that the problem is not related to any software or the installed operating system itself.

About the broken LCD or laptop - You can always replace the faulty parts of your laptop and if needed, even the motherboard can be replaced altogether to bring your laptop back to life. You can get all the required information about the parts of your laptop from the guide available here.

Bottom Line
Since the complexities (if any) generated in the BIOS chip and/or motherboard due to desoldering and resoldering cannot be undone, you may want to use the laptop for as long as possible and go for troubleshooting and repairing only when the computer is dead. When this happens, you may also want to take your laptop to a Lenovo's authorized service center and let the certified professionals do the job for you. :)

Hope this helps.
 
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