Question Thinkpad X1 Carbon 4th gen refuses to stop throtteling after minor spill

Jul 15, 2020
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So after a minor encounter with some coffee my Thinkpad X1 Carbon is permanently throtteling the processor to 0.4Ghz (minimum speed) and i am absolutely stumped as to why at this point.

What happened:
  • I spilled some coffee over the keyboard (still works) and in the side of the machine.
  • Most of the inside of the laptop remained clean but some liquid sept under the protective plastic on the pcb.
  • After cleaning everything i noticed the laptop still works fine but the processor is permanently stuck at its minimum core speed.
  • Intel XTU and ThrottleStop report the processor as both thermal and power limited.
  • The Battery does not charge
What ive already tried:
  • Using ThrottleStop to remove "BD Procrot" (thermal throtteling) works for the thermal limit, but since the processor is power limiting too it still runs slow.
  • All Lenovo Diagnostics/Tests run with no errors (except the Battery charge test)
  • Reset the Laptop by holding the power button ~30secs with no AC attached (dosnt work)
  • Reset the Laptop by pressing the reset button on the bottom (didnt work)
  • Reset the BIOS (didnt work)
  • Reinstalled chipset and intel framework drivers (didnt work)
  • Started Ubuntu 20.04 from usb stick (didnt work the laptop throttles the exact same way in Linux)
  • Checked settings in XTU (didnt work, everything is at stock speeds/settings)
  • Checked windows settings like power plan etc, everything is set to maximum performance
  • Tried to disable SpeedStep in BIOS and manually set processor clock. (didnt work, processor ignores setting and still runs slow)
  • Tried anoter AC adapter (didnt work)
  • Replaced the Battery (didnt work, exact same symptoms)
  • Cheked windows system logs. Windows reports the processor beeing limited at system level, nothing else.
  • Checked if the AC Adapter is powerful enough to support the tdp of the laptop (65W > 25W max TDP on the package)
Can somebody here help me? Ive been trying for weeks now to fix this thing. I hope this is some sort of software bug, since the system itself is running perfectly fine, it just dosn't use its power.

Many thanks
-Dave
 
Jul 15, 2020
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Since this happened after a spill I don't see how it can be anything to do with software unless your coffee somehow got into the operating system and changed things. You will probably need a new motherboard.
Thanks for the reply. You've got a point, however buying a new Board (or a new Laptop) is expensive and i don't have that kind of Money atm.
What baffles me is that: if something on the Board (a fuse, sensor, capacitor or something) blew and does not work anymore, why is the laptop still running? If something hardware related is truly broken, the whole thing wouldn't run or even boot right?
So i figured that, if the laptop works fine and just dosn't use its processor correctly it has to be software related and therefore fixable.
 
Throttling is usually heat related.
Are your cooling airways clear?
Are the cooling fans running?
Possibly, you could remount the cpu cooler.

Are you running on battery or on wall power?
Possibly, your battery has been shorted out and needs a replacement.
Try to buy a true oem battery, not some cheaper "compatible " unit.
 

hang-the-9

Titan
Moderator
Thanks for the reply. You've got a point, however buying a new Board (or a new Laptop) is expensive and i don't have that kind of Money atm.
What baffles me is that: if something on the Board (a fuse, sensor, capacitor or something) blew and does not work anymore, why is the laptop still running? If something hardware related is truly broken, the whole thing wouldn't run or even boot right?
So i figured that, if the laptop works fine and just dosn't use its processor correctly it has to be software related and therefore fixable.
A system can still run but have broken parts in it, happens all the time with video cards, people say "well the video card fan is spinning how can the card be bad" or "the card works fine in Safe Mode". If you think about what happened, you had a spill, after that the system stopped working properly. So what in software could have possible changed during that time? How can a spill cause the installed software to change?
 
Jul 15, 2020
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Throttling is usually heat related.
Are your cooling airways clear?
Are the cooling fans running?
Possibly, you could remount the cpu cooler.

Are you running on battery or on wall power?
Possibly, your battery has been shorted out and needs a replacement.
Try to buy a true oem battery, not some cheaper "compatible " unit.
Thanks for the reply, the cooling seems fine. The fan is spinning if i test it with lenovos testing utility, in normal operation it does not spin up (i think because the cpu dosnt get hot enough since its only running slow).
As i reassembled it i remounted the cooler aswell, so i dont see it coming from there.

As for the AC, since the battery is drained im running on wall power. I did buy a new battery (sadly only compatible not OEM) but when i installed it i had the same symptoms. Laptop running slow, regardless of wall or battery power and no charge beeing put into the battery.
 
Jul 15, 2020
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A system can still run but have broken parts in it, happens all the time with video cards, people say "well the video card fan is spinning how can the card be bad" or "the card works fine in Safe Mode". If you think about what happened, you had a spill, after that the system stopped working properly. So what in software could have possible changed during that time? How can a spill cause the installed software to change?
True true. The thing is we are not talking about a broken gpu with fans running but about a laptop board with everything on it functioning (almost) properly. I do not think Lenovo would print a second, low powered circuit for running every system component in case the fist power delivery blows right? And even if, why isnt it documented somewhre?

I know from other posts about similar issues in different mashines (Lenovo and non Lenovo) that several people have fixed similar issues by a combination of battery/bios/cipset resets.
Sadly i did try all the methods ive found and none of them worked so im mainly asking if someone knows something else i can try.

i mean there could be some safety trigger mechanism for liquid damage in these laptops that has to be un-triggered for it to work properly again
 
Some batteries have chips inside that are required for proper operation.
That is why "compatible" replacements sometimes do not work.
Your X1 carbon is a very good laptop.
Why not send it back to Lenovo for repair?
 

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