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What's DOS?
Posts: 4
Registered: ‎03-11-2015
Location: Melbourne
Views: 655
Message 1 of 2

ThinkPad Edge E320 intermittent screen fault - CMOS related?

Heya all, I've been given a ThinkPad Edge E320 to troubleshoot/keep/scrap for parts, or any combination of the above. What the issue is that the internal screen doesn't initialise (the backlight lights, but no information on screen - not even the Lenovo boot logo), but the system still seems to boot alright.

I've found that if I remove the yellow CMOS battery and let the system sit to drain, the internal LCD panel works just fine, and if you leave the CMOS battery unplugged it continues to work fine. However as soon as you plug in the CMOS battery and save the configuration, the problem starts again.


Hooking up an external monitor and pressing Fn-F6 shortly after turning it on makes it work fine on the external display, so I'm confident the system board itself is (mostly) fine, and that it's some invalid data in the CMOS that's causing the system to ignore the internal display, or at least not send any data to it.

Does anyone have any ideas? I've tried different CMOS batteries (I have a few with the same connector from some old X60s and T60s I've scrapped for parts) and it doesn't seem to make a difference. I've also tried updating the BIOS to the latest version in one of the times I was able to get it to boot fine.


Also tried clearing the CMOS settings, checking that "ThinkPad LCD" is the selected startup display, etc. This system only has integrated graphics, no discrete video or switchable graphics.

Another thing I've checked for are loose LCD connections (on both sides), any places where the system board shorts out on other places such as the back of the keyboard and HDD bay (which seem to be two common trouble spots), but the issue is quite repeatable/resolvable with the CMOS battery pull.

Any ideas? I've never seen anything quite like this before..


(One thing I just thought of, the BIOS update I did updated the system BIOS but not the embedded controller.. I'll try using a much older BIOS with a different EC version and see if that gets it out of its funk)


What's DOS?
Posts: 1
Registered: ‎06-18-2015
Location: Czech Republic
Views: 538
Message 2 of 2

Re: ThinkPad Edge E320 intermittent screen fault - CMOS related?

Hello! I have precisely the same problem. Did you solve it by upgrading the BIOS?

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