English Community

ThinkPad NotebooksThinkPad: T400 / T500 and newer T series Laptops
All Forum Topics
Options

8 Posts

05-01-2019

United States of America

8 Signins

179 Page Views

  • Posts: 8
  • Registered: ‎05-01-2019
  • Location: United States of America
  • Views: 179
  • Message 1 of 4

T430 Boot Up Power Problem when cmos or battery connected. Won't boot

2019-05-09, 17:04 PM

Have a T430 Lenovo ThinkPad on my hands, 430i to be precise. That has got me perplexed.

It originally did not turn on.

After hours of diagnostics I have narrowed it down to.

Turns on with cmos backup battery removed. But also main battery removed. Voltage reading on battery show 3.04 v so that seems good.

Gives error msg of " 0251: System Cmos Checksum Bad

(also) Real Time clock error.

After adjusting settings, time & saving. It will turn on and restart. (with or without battery) Until I pull the power cord and then try to start it.

Then, no matter how long I disconnect the power, how many times I press the power button ( tried the 10x trick then hold for 30seconds)

Will absolutely not boot with cmos battery connected after its had its time set proper.

 

The battery did charge and holds a charge. It will not boot from main battery alone with cmos disconnected either. But once you have it booted from power plug without cmos and then put in battery and pull power plug.

It will stay on an utlize the battery just fine.

 

 

I have flashed the bios to the latest 2.79 via using bootable cd image.

In the process I have done a complete teardown reassembly of this thing. Removing all componenets one by one.

 

Things that I have tried.

*Disconnecting the webcam.

*Reseating the CPU and reapplying thermal paste.

*Swapping memory sticks with higher rated ram and testing separate memory banks in isolation

*leaving components disconnectedand reconnecting  one by one and reconnecting

 

I guess the only thing I haven't tried is booting it with keyboard completely disconnected, but then not sure how to power it on without keyboard power button.

 

Anyone have any ideas as the t430i is

*confirmed to charge main battery.

*Boots without cmos.

*Boots from ac adapter only but will work after plug is pulled

 

Confirmed cmos voltage of 3.03 confirmed ac adapter voltage of 20v.

 

Just to be 100% sure, replaced it with a new cmos battery reading 3.26. Issue persists

 

Seems that this issue also affects t420 t530 e532 T530 X260 from the searching and reading I've done. 

 

Anyone have any ideas or suggestions ?

Reply
Options

11715 Posts

01-02-2010

United States of America

40010 Signins

420769 Page Views

  • Posts: 11715
  • Registered: ‎01-02-2010
  • Location: United States of America
  • Views: 420769
  • Message 2 of 4

Re: T430 Boot Up Power Problem when cmos or battery connected. Won't boot

2019-05-09, 18:09 PM

Ther power circuitry is probably bad, but there is one thing I would check if you are not the original owner.  There is a white plastic socket where the CMOS battery is connected to the motherboard,  I have seen that socket pulled off when unplugging thye battery and installed backwards.  If that happens, the terminals are reversed when plugged in.  There should be a designation on the motherboard as to which pin is positive.  They may be numbered 1 and 2 or maybe just number 1 is marked.  Number 1 is the positive terminal and the wire is probably red.  White is normally the neutral or ground. 


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

8 Posts

05-01-2019

United States of America

8 Signins

179 Page Views

  • Posts: 8
  • Registered: ‎05-01-2019
  • Location: United States of America
  • Views: 179
  • Message 3 of 4

Re: T430 Boot Up Power Problem when cmos or battery connected. Won't boot

2019-05-09, 20:23 PM

Gave it a try. I made my own cmos battery using the cable so reversed the leads. It is sort of an improvement. 

Good thing is I now don't have to replug the cmos every time :) It does not save settings nor boot from laptop battery still. Since  I assume it shorts the settings by being reversed :)

 

For anyone in my shoes.

I'm going to try this later on https://www.reddit.com/r/thinkpad/comments/99hx8q/turning_on_a_t430s_without_the_power_button/

To make sure it isn't the keyboard.

Reply
Options

1 Posts

12-31-2020

Saudi Arabia

1 Signins

0 Page Views

  • Posts: 1
  • Registered: ‎12-31-2020
  • Location: Saudi Arabia
  • Views: 0
  • Message 4 of 4

Re:T430 Boot Up Power Problem when cmos or battery connected. Won't boot

2020-12-31, 20:02 PM

I have the same problem of my laptop model is ideapad l340-15iwl I can power it on until I pull out the CMOS Battery. is there any solution of my problem? or when can start to troubleshoot my laptop?

 

Reply
Forum Home

Community Guidelines

Please review our Guidelines before posting.

Learn More

Check out current deals!

Go Shop
X

Save

X

Delete

X

No, I don’t want to share ideas Yes, I agree to these terms