English Community

ThinkPad NotebooksThinkPad: P and W Series Mobile Workstations
All Forum Topics
Options

3 Posts

09-08-2019

US

11 Signins

92 Page Views

  • Posts: 3
  • Registered: ‎09-08-2019
  • Location: US
  • Views: 92
  • Message 1 of 6

P51 Charging Issues

2019-09-08, 7:30 AM

I have seen several posts on this subject, but nothing that has answered my question.

Beginning last week, every time that I start up my Lenovo P51 laptop, I receive the following error:

"An unknown adapter is connected to the system. To use AC power, please conect the AC adapter that was shippe with the system."

I am using the adapter that was shipped with the system.

On the day the problem began, I made two changes to the syestem: I added an 2nd SSD drive (Intel M.2 660p 2TB), and I upgraded from Windows 10 pro version 1803 to 1903.

 

I have tried the following fixes, all with no result:

1. Lenovo Support's recommendation - unplug everything, remove battery, hold power button for 60 seconds, put everything back, and restart

2. Uninstall and reinstall battery and power management drivers

3. System revert to before the update, and remove 2nd SSD

4. Backed up all files and completely reinstalled Windows

5. Airplane mode is not and never was activated

6. The connectors are not dirty or bent.

7. Lenovo sent me a new adapter, but it did not help.

 

The laptop does charge when powered off, but slower than it used to.

 

I would greatly appreciate any ideas.

Solved! See the solution
Reply
Options

11269 Posts

01-02-2010

US

39719 Signins

415313 Page Views

  • Posts: 11269
  • Registered: ‎01-02-2010
  • Location: US
  • Views: 415313
  • Message 2 of 6

Re: P51 Charging Issues

2019-09-08, 14:54 PM

Since Lenovo sent you an adapter, I assume you are still under warranty.  Call them and tell them your situation.  It sounds like the power circuitry is not correctly identifying the resistance on the signal pin. (motherboard problem)


Rich


I do not respond to requests for private, one-on-one help. Your questions should be posted in the appropriate forum where they may help others as well.

If a response answers your question, please mark it as the accepted solution.

I am not an employee or agent of Lenovo.
Reply
Options

5 Posts

12-12-2019

US

3 Signins

72 Page Views

  • Posts: 5
  • Registered: ‎12-12-2019
  • Location: US
  • Views: 72
  • Message 3 of 6

Re: P51 Charging Issues

2019-12-12, 19:02 PM

I have a similar issue with a brand new P53 that I just received yesterday.

 

1. unboxed brand new P53

2. plugged in the included Lenovo 170W AC power adapter, and booted in default configuration (Windows). Went through required basic setup (no issues)

3. used machine for ~20 minutes to make sure things were running OK (connect to wifi, browse internet, etc.)

4. shutdown machine

5. added additional RAM + a 2nd M.2 SSD (followed the procedures here, including temporarily disabling the battery in the BIOS: https://support.lenovo.com/us/en/solutions/ht509006)

6. boot the machine back up: additional RAM was recognized, but SSD was not

7. shut back down and re-seated SSD, after which it was recognized.

 

Now, when recycling the machine, I get a Lenovo warning about the AC power adapter not being recognized (this is prior to booting into the OS).   The warning is this (complete with typo):

 

An unknow adapter is connected to the system. To use AC power, please connect the AC adapter which was shipped with the system.  

Press the ESC key to continue

 

The machine will continue to boot up if you press F1, but the battery will drain even though the AC power is plugged in to the point it is eventually at 0% whereupon the machine will shut down.

 

I have tried numerous things to resolve this

 

1. I have tried 3 other standard issue  Lenovo 170W power adapters (plugged directly into multiple different wall outlets)

2. I have removed the additional M.2 SSD

3. I have removed the additional RAM

4. I have tried disconnecting the battery, and holding the power button down for 30 seconds

5. I have tried booting with the AC power plugged in (and battery removed).  No dice - won't boot, acts like there's no power

6. I have tried re-selecting the BIOS option to temporarily disable the built-in battery (as shown here  http://download.lenovo.com/lts/RTPW10M0/FOF/RTPW10M0-P53_REM_FRU_00_DisableBuilt-inBattery.mp4).

7. I have tried resetting the BIOS to its default values

 

Nothing seems to resolve this.

 

Any ideas?

 

p.s. also recapped as top-level post here: https://forums.lenovo.com/t5/ThinkPad-P-and-W-Series-Mobile/Brand-new-P53-AC-Charging-will-not-work/td-p/4599758

Reply
Options

3 Posts

09-08-2019

US

11 Signins

92 Page Views

  • Posts: 3
  • Registered: ‎09-08-2019
  • Location: US
  • Views: 92
  • Message 4 of 6

Re: P51 Charging Issues

2019-12-12, 20:09 PM

After trying everything, I eventually sent my P51 in to a Lenovo service center (under warranty). They called me a few days later to say that they had taken it apart, found nothing wrong, and reassembled it - after which it began to work properly. They told me to pick it up, without explaining further. Since then, I have had no problems.

I can only surmise that there was a lose connector or something of the sort in the laptop itself, effectively lowering the wattage entering the device, and thereby preventing the computer from charging while consuming power, as well as from recognizing the charger, since it seemed not to be providing the correct wattage.

Reply
Options

5 Posts

12-12-2019

US

3 Signins

72 Page Views

  • Posts: 5
  • Registered: ‎12-12-2019
  • Location: US
  • Views: 72
  • Message 5 of 6

Re: P51 Charging Issues

2019-12-12, 23:35 PM

Thank you for your reply @EliK90.

 

After reading your response, it occurred to me that perhaps I should check for loose connections on the back-side of where the AC adapter connects to the back of the P53.

 

I re-seated the ribbon that is directly behind where the power connects, and that fixed the issue!

 

Annotated screenshot below

 

 

 

Thanks again for sharing your experience. It was helpful ;)

 

0 person found this solution to be helpful.

This helped me too

Reply
Options

1 Posts

09-18-2020

VN

2 Signins

10 Page Views

  • Posts: 1
  • Registered: ‎09-18-2020
  • Location: VN
  • Views: 10
  • Message 6 of 6

Re:P51 Charging Issues

2020-09-19, 9:08 AM

I faced this issue and even I tried with a charger 230w but this problem still occurs.Your suggestion saved my day!!! 

 

My brother has done a video to reproduce and resolve this issue. Hope it can be useful for others.

 

https://www.youtube.com/watch?v=yq5fLjvGVsk&feature=youtu.be&fbclid=IwAR3uF4MCCkbhyxYscfOcphKj_4rHNSLe74i76poroICVHCAlzaIAXQVBbIc

Reply
Forum Home

Community Guidelines

Please review our Guidelines before posting.

Learn More

Check out current deals!

Go Shop
X

Save

X

Delete