Laptop won’t power on, possibly related to airport security

Question

On two occasions in the past week, my Lenovo T440s has failed to start up after passing through US airport security [edit: see bottom] and taking a flight. When I press the power button, absolutely nothing happens (no BIOS, nothing), even when the AC adapter is plugged in.

Each time, I resolved the issue by removing the case, disconnecting the internal battery, holding down the power button for 60 seconds, plugging in the AC adapter with the internal battery still disconnected, and powering on the laptop. This caused the laptop to power on successfully, after which I shut it down, reconnected the internal battery, and closed the case.

(Only a standard Phillips screwdriver was required, as well as some wedge to open the case—a flat screwdriver will do if you don’t have a spudger. For what it’s worth, I’m very pleased with the repairability factor.)

Here are some facts:

• The machine was powered off at all times during the airport and flight process, and never left my physical possession except to pass through the standard security scan.
• On one occurrence, the machine was in a soft laptop case inside a backpack; in another, it was exposed in a bin.
• Usually, plugging in the AC adapter causes the power light to flash three times, regardless of whether the machine is on or off. In this case, plugging in the AC adapter did not cause the light to flash. I cannot find any references to this behavior elsewhere on the web.
• The machine is from May 2014 and has never had any previous issues with the power system.

My questions:

• Why might this be happening?
• Why might this be happening now?
• What can I do to prevent this from happening in the future? (One idea: before going through security, disable the internal battery in BIOS; then, after the flight, remove the internal battery and drain the capacitors so that I don’t have to physically open the case. But this is still very much a workaround.)

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Edit to add: This has since happened once without passing through airport security, so the relation may be less direct than previously thought. I disconnected the laptop from its power supply, shut it down normally, and drove to a different location. There was nothing strange about the source, destination, or drive; I did not pass through any tolls, checkpoints, etc., and I was not in a collision. At the destination, the laptop failed to start up. The same fix applied.

Answer 1

I did have a similar experience years ago while travelling (in Europe) after the notebook was left in the X-ray machine much longer than usual - the operator of the machine had a trainee, whom he wanted to familiarize with how different types of laptops look under the scan.

This was an older model (C2 generation), and I could only resolve it by opening the case and clearing the NVRAM via the "clear CMOS" jumper. I remember, that at that time I suspected a bit flip in the NVRAM, that prevented the early boot (hardware initalization) phase.

Your experience is close enough to mine, that if you fly regularily you might want to try sticking a small (1"x1") piece of double layer tinfoil in the case over the MVRAM chip.