Question Lenovo X1 Carbon rebooting. Maybe grounding issue?

Conspiracy5

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Mar 18, 2011
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For starters, I have read everything I can find on random reboot issues and so far can’t find anything that matches my situation. Also I only know enough to be dangerous.

My older (not sure exactly which generation but perhaps 3rd) X1 Carbon just started giving me frequent and random reboots. Over three days of troubleshooting I had (based on event logs) maybe 95 reboots while managing to stabilize for about an hour at one point. System runs windows 10 and would reboot anywhere between the black screen with the blue window to the password page and even occasionally giving me a few seconds of desktop time. I was skeptical of software issue since the moment of reboot was inconsistent.

The use or lack of use of the power cord has no apparent affect on the problem.

I managed to...
load a restore point from a couple days prior to the issue.
I rolled back a recent windows update
Ran SFC and DISM several times to repair corrupt OS but it revealed nothing
Inspected event log and repaired some 1084 errors

During the end of this process I had the machine running smoothly for a couple hours but it was all mouse work. The very moment I picked up the laptop it crashed. I set it down, let it boot and got to work again on cleaning the event log. After a couple hours I again moved the laptop and as before, it crashed at that moment.

So I’ve opened the thing up

Nothing looked out of the ordinary but I put some gloves on and poked around. Removed the battery for a bit, checked that everything was seated well, reinstalled battery. Hoping for magic I turned it on but the problem remains and the most consistency is with moving the thing. So poking around with it running... don’t yell at me... I found an area on the fan cooling tubes that when I give the slightest push it reboots as if that were a secret button. Now you may be saying, “of course, dummy, you can’t touch that when it’s running.” But oh well. I found a Lenovo manual that specifically says not to touch the fan area (with a diagram) when replacing it but the cooling tubes are not in the depicted area. So I’m wondering if this contact is shorting something out or there is a grounding issue and even the keyboard above it interferes with this grounding. Once I trip it it my boot up fine again or reboot a few times before settling down.

I should add that touching this tube isn’t exclusively setting off the reboots but as long as it just sits there I can do some work. I’ve left it open with a screwdriver handle wedged between the two pieces so nothing is contacting the heat sink area at all. In this condition I can reliably work at the desk but every once in a while it will reboot. It hasn’t been enough yet to see how that relates to the load on the computer. I do have a 120mm case fan blowing a lot of extra air into it so i would think it’s adequately cooled.

Sorry so long but trying to provide all the info up front. So any ideas or suggestions? If I’m right about grounding is there anything I can do about it? I rarely work at a desk so keeping the laptop still going forward will only limp me through these next two weeks before I get back home but I certainly can’t watch Netflix in bed or work on a plane. Thanks in advance.


I believe I have ruled out OS issues and software.
 

Ralston18

Titan
Moderator
It does indeed seem as if movement or pressure is causing a short.

The key will be to identify the specific point where metal touches metal and find a way to prevent future/further contact.

There may have been some simple spacer or insulator in place that deteriorated, came loose, and thus allowed the short to occur.

Since you have already been poking about does it appear that anything is loose? Maybe just needs some gentle tightening here and there to hold all components in place.

Or perhaps an interim solution to insulate the points with a small piece of real electrical tape.

In any case, whatever you do, power off and unplug.

Do not push your good luck again....
 

Conspiracy5

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Mar 18, 2011
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Everything seems solid except a usb controller because the case screw also holds it in place so it currently only has one screw. Thinking about the MOBO I took the screw driver and even though it didn’t seem to have a play I poked the screw on the corner near the fan where I was noticing the reboot reaction and that tripped it. So something in that vicinity is shorting. I guess I need to rip all the guts out and inspect the underside of that board.

So rather than that,

I removed the screw and wedged a small piece of rubber between the case and that corner of the mobo. It will still short out if I press that region but I have to actually apply a little pressure not just a slight tap so the spacer is having an effect. What’s troubling is load still seems to be a factor. I fired up a first-person-shooter game and it only lasted a minute. It’s Day of Defeat Source so not an intense game for this business laptop (gen 1 confirmed, circa 2012). I downloaded a system monitor and started a log running. Then fired up DoD Source again. I didn’t play, just joined a server and walked away. No contact with computer at all. It still crashed about a minute later. According to the log, CPU temperatures didn’t get above 73 degrees C so I don’t think heat is the problem unless there is a real weakness somewhere. Reinstalling video drivers has no effect.

Any other ideas or tips on how to correct the short. My next thought is to me move the fan, inspect hidden area, and reinstall fan but I need to get my hands on some thermal paste first. Better ideas?
 
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