Released in 2018, the 6th generation ThinkPad X1 Carbon is one of Lenovo's popular performance business laptops. Model number: 20QD000BUS

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Laptop Rarely Boots when Power Button is Pressed?

Hi there,

I have a Lenovo ThinkPad X1 Carbon 6th Generation. It is an awesome device and it used to work flawlessly.

Recently, I am facing the problem that the laptop, when shut down, refuses to boot after pressing the power button. Instead of booting, the power button and keyboard lights briefly flash, the fan turns on, spins at most 1-2 seconds, and everything turns off again. When I keep hitting the power button often enough, like 20 to 100 times, the procedure repeats and at some point the laptop boots normally and everything is fine. I also noticed that very seldomly, when the laptop is in standby, it turns off and then refuses to boot, too. Besides that, the laptop works perfectly, once booted and there is no other problem at all.

I tried to search on Google but could not find any matching error description. Are there any suggestions on your side what the cause might be, how to debug this, and how to fix this?

Thank you very much in advance!

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Hi @mrbuuuffed,

What is the model number of the laptop, as shown on the information label on the bottom of the laptop?



Hey, unfortunately, there is no information label on the bottom of my laptop. But printed on the back of the laptop it says "6th Generation Thinkpad Carbon X1" and with dmidecode I get the following "product name": 20KGS03800. Does that help already?





Hi @mrbuuuffed ,

Try disconnecting the main battery and the coin cell battery in the laptop and then press and hold the laptop's Power On button for a full 30 seconds and then release it.

Here's the hardware maintenance manual for the laptop. Go to p.70 and p.78 to view the necessary pre-requisite steps and then the procedure to remove the battery and the coin cell battery respectively..

Whilst you have the coin cell battery out, measure its voltage. If it is <2.5V DC replace it. The part number for the coin cell battery is 01HY008. Search online using the part number only in the search box of your browser, to find suppliers that suit you best.

Reconnect the coin cell battery and the main battery, re-assemble the laptop, connect the charger and try turning it on.

If it turns on there may be a message about the date and time being incorrect. This is normal as the BIOS has been reset to its factory default settings. Once the date and time have been corrected the message won't appear the next time the laptop is started. Also if you altered any user definable settings in BIOS to suit your particular operating requirements they will have to be set again.

Update (05/05/2022)


You just measure across the coin cell battery plug's red and black wires. If the plug is narrow sometimes inserting thin wires into the plug and then connecting to them works.

Although this battery is not the problem now, as performing the refresh should have reset the BIOS if it were a corrupted BIOS problem that you're having with the laptop and it should have started.

I'm now wondering if you have a faulty power on button.

IF the motherboard is model number NM-B481 REV: 1.0 (printed on motherboard) then here's an image of the lid switch connection.

Use an Ohmmeter to check that when pressed there is an earth on pin 3 and that it is not there when the button is not pressed i.e. sticking contacts perhaps. Disconnect the battery when trying this

If it is OK then here's a link to the schematics that may help. Again this is only applicable if the motherboard's model number is the same as for your motherboard. If not what is the model number of your motherboard?

Block Image

(click on image to enlarge)


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I've never seen a primary battery cause issues; it's always just the stinking CMOS battery.

2.5V cells usually work but are "risky" as they can cause the same corruption problems. It's not a permanent condition, so I'll take that chance as long as it's a one-time incident.

Win11 throws a new wrench in on *SOME* laptops which rely on fTPM, but these ThinkPads use a dedicated TPM; very early warning so you know about this on "fTPM" laptops on the consumer side.



True but the idea is to remove all the power from the motherboard to guarantee that everything will be discharged and reset.



@jayeff I disconnect both for this, but oftentimes you can keep the original CMOS battery installed. For a normal user if it's suspect replacement is better then having to repeat it but I know if I have a laptop I didn't replace it on, I may need to "field fix" the issue again - even if it means taking the laptop apart in the mall food court.

Since taking a laptop apart in a food court is weird, if I took my 7490 out I KNOW I disconnect and fixed I may replace it with a new one then if I recall it being suspect (after checking), but 95% of the time they're still reasonable at 2.9-2.7V.

2.6V is marginal enough I'll throw it into the repairs if I'm checking something else, like installing an SSD on a "no SSD" machine because it was removed or migrating to NVMe on a NVMe ready unit that had a used SATA drive installed for quick sale, but I'm not fussy as long as it doesn't cause more issues at that time.


Hi there, this is mrbuuuffed! First of all, thank you very much for taking the time to answer my question! I did try as you described by removing the main battery and the cell battery, pressing the power button for 30sec, adding the batteries back, connect the charger, and try again. Unfortunately this had no effect, it still does not boot. I wanted to measure the voltage of the cel

Battery, but it is wrapped in a yellow piece of plastic and out of this plastic there are only a red and a black cable coming. Can you tell me how to measure this battery? Can I just remove the plastic? Thanks, mrbuuuffed!


Hi there, thanks again for you answer! Regarding the power button, I am wondering, because when I press the button, the laptop tries to boot (fans start spinning and stop immediately again) and the light of the power button, the esc key etc, turn on. Wouldn’t that indicate that the button is working?

Also, it might be important to mention that so far, when I tried often enough pressing the button, eventually the laptop turns on and works flawlessly for days/weeks. However, yesterday evening It was turned on but the battery went empty. Since then, although charged again, it does not boot any more. No matter how often I hit the power button, the lights go on and off, etc.

I wonder, if there is anything else I could do as if the motherboard would be broken, it shouldn’t run at all any more, should it?




That can either be a motherboard issue, dead CMOS battery or simply a corrupted CMOS RAM screwing with the bootup. Dells are also easy to corrupt, so I've scored cheap Dells I have no business owning for what I paid ($140 for a i5-8350U listed as an 8250U LG IPS without RAM/SSD) and all I needed to do was remove the CMOS battery and keep the primary disconnected until I seen it boot. No replacement was done.

I wasn't expecting IPS for $150, much less LG IPS. That was a big deal with Samsung out of the TFT game (they were always my budget IPS favorite - losing them was kind of a bummer). All we have left is BOE and LG for TFT LCDs, since Samsung ships OLED laptop screens now, and QLED desktop monitors. Even if the laptop was hosed for $150, the LG IPS display paid for it because I could drop it into a BOE laptop, or a TN 768p which is otherwise well equipped.

These are super easy too (but not as easy as my $150 Dell) -- you need to remove the main battery to get to the CMOS battery if you need to completely remove it, but it is right there. Refer to this guide: Lenovo ThinkPad X1 Carbon 6th Gen Battery Replacement - iFixit Repair Guide


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