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My Dell XPS 15 laptop has an SSD. As far as I know it has only 2 moving parts besides buttons, the hinge and the fan.

I dropped it on concrete while it was in sleep mode. On opening the lid, the login screen showed. The touchpad responded for about 2 seconds and then it all froze. Tab, space, enter, volume and brightness keys all had no effect.

The unexpected (to me) behavior is that I restarted it via the power button, and it booted up normally. It does not normally freeze on wake from sleep.

What could cause this behavior? My understanding of computers is that if a mechanical shock is sufficient to disrupt operations immediately, that is because somewhere some electrical conductor in the machine has broken. That should permanently disrupt operations, not temporarily. What am I missing?

thechimp
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  • I would ascribe that to physical *connectors* flexing and losing their connection. That the laptop then boots normally after having hit concrete, sounds more like luck... I would strongly suggest running every diagnostic under the sun. – MiG Mar 06 '22 at 12:18
  • A lot of modern connectors are sprung contacts. They're used used for battery connections, DIMM slots, SATA connectors and other things and sufficient force could disconnect a power connection briefly. That *might* cause a disk controller on the drive to reset unexpectedly and cause the initial crash behaviour that you see. Then when you reset it everything is already good and the system just goes on normally. Just a guess. – Mokubai Mar 06 '22 at 13:20
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    The RAM chips can be knocked lose. There is nothing in the laptop, other than a spring loaded clip that holds them in place. They are able to slide out of the slot with enough force. In this case, I would always reseat the RAM and then perform a memory test while gently tapping on the RAM modules to insure they are solid. This happened while the laptop was asleep, so most devices are powered off - except the RAM! All the app/OS memory was still being maintained in RAM. A small interruption would corrupt RAM & freeze everything. Not uncommon at all, but if knocked lose could cause more trouble. – Appleoddity Mar 07 '22 at 06:32

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While you have no moving parts that would affect the usage of the computer, a strong enough physical shock can still cause issues. As @Mokubai mentioned in his comment, many connectors are spring loaded, meaning they use pressure to maintain contact. A shock could temporarily disconnect the connectors. This can also happen if the motherboard flexed in the drop. Even a small enough twist could separate contact points and break the circuit. Another issue, although less common on new hardware, is that a shock could break solder joints. Broken solder joints are fixable, if found.

If your laptop is working normally, then you probably are fine and just had a one-time issue. If you see irregular behavior in the future, you might want to have the laptop checked.

Keltari
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  • The link/image is broken – mashuptwice Mar 06 '22 at 16:06
  • @mashuptwice ty. fixed. – Keltari Mar 06 '22 at 19:27
  • Spring loaded contacts in internal connectors is intuitive. Flexure of PCBs sounds more like the "permanent" break I was imagining. You're saying that the crack across a PCB trace would open during the flexure during the shock, but be closed when the board is at rest? – thechimp Mar 08 '22 at 04:39