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Laptop loses power when moving screen

I dropped my Lenovo Yoga C740-15IML on the corner where the power button is and damaged it pretty well—the bottom, back and side metal housing are all slightly bent now as a result.

The laptop powers on fine still (!!) but when you move the screen forward or backwards the laptop loses power—not just the screen powers off but power is lost to the entire machine and it goes through a disk repair cycle when it restarts (assuming because it wasn’t powered down correctly). It works properly if the screen is open at a specific angle, but if you move the screen any from the spot it loses power

Any suggestions on how to repair? If I open it up, what are the things I should be looking for and/or ready to replace? Thanks!

Répondre à cette question J'ai le même problème

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Hi @edthomas25 ,

If the case is bent out of shape check that all the internal cable connections e.g. battery, IO board etc are secure as moving the lid may cause movement in a loose connection. Also check for any obvious damage around the power button area.

Looking at the hardware maintenance manual for the laptop, the power button is on the IO board (part #5C50S24992 - supplier example only to show the part), which connects to the systemboard.

Hopefully this is of some help.

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Thanks, this helps!

When I open up the laptop, will it be fairly obvious if one or more of the power cables or connections are out of place or no longer connected securely?



You may have to gently try moving them to find out.

Also it may be obvious with the cover removed and you move the lid that you can see what's happening.

If you go to remove anything from the systemboard disconnect the battery first. You don't have to remove it, just disconnect it. There is always power connected to the motherboard even when the laptop is off. The power button is not a power isolating button. Its function is to signal the BIOS. Think of the laptop as being in an extremely low power state when off and not that it is disconnected from any power. You don't want to be causing any electrical problems if you accidentally slip when using tools or touch something you shouldn't. Also wear a wrist strap tied to an earth point to prevent ESD damage.


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Unless the case is bent, screen movement will only move the cables supplying the screen with power and video.

In that case, I would first look carefully at those cables (usually 2, one flat and one wire) to determine if they are shorting out against the case. You will have to open it up. Removing the kbd might give u enough visibility but u may need to open more up or even remove the screen. It could also be that movement of the screen cables is interacting with the power circuit. In any case, your shutdown is either because the power opened or shorted creating an immediate power loss.

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Same happened to me, moreover the battery is drained each time.

The board looks fine but the lapop runs fine when the bottom cover is removed...

Hmm looks like its not going to be easy to find the faulty cable or connection

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HI @mrk7777,

If the case is bent then when moving the lid it may be flexing the base (and the motherboard because it is fixed to the base) so maybe just try reseating all the cables i.e. remove/reinsert and then try it reassembled.

Also check that the motherboard isn't touching parts of the base enclosure, that it shouldn't be when the lid is being moved.


AGAIN, If the LT shuts down when you move the screen, it is moving a cable and the cable is SHORTING OUT POWER. Otherwise, anything loose would only affect the screen. If it shorts power, it might also kill the battery or cause it to temporarily shut down due to high current. The screen has either 1 cable or 2. If 2, pull the screen power and see if it shuts down. If not, that is where your short is. If so, pull the other cable.

It may be a little tricky to do, but that is how you will figure it out - unless you can eyeball the problem.


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Ed Thomas sera éternellement reconnaissant.
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