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twenty
Blue Screen Again
Posts: 2
Registered: ‎12-10-2014
Location: London
Views: 2,168
Message 1 of 11

W520 infinite reboot loop even before BIOS screen

Hi Everyone,

Earlier today I noticed that my w520 had not gone into sleep mode properly when I shut down the lid yesterday night. The fan was turned on, the CPU side warm to touch and the power button with green led on. The laptop didn't respond to any key or mouse input, so I just pressed and held the power button till the machine shutdown.

 

Once I turned on the laptop again, pressing the power button, the laptop went into a reboot loop! Unlike some reboot loops reported in this forum, mine does not even display the Thinkpad BIOS screen. The Power LED indicator comes on for a second, with the CAPS lock, Bluetooth and WLAN LED indicators lighting up at the same time and then the machine shuts down and reboots again and the whole thing starts over again. The only way I can stop the reboot loop is to press and hold the power button for about 10 seconds once the power is on for the brief period. Turning on the machine afterwards again results in the same reboot loop!

 

So far I have tried taking out the battery and tried starting it using power from the docking station and same thinng keeps on happening. I don't have an external monitor at hand right now, so I can't even tell if it's some weird display driver issue. I haven't taken out the primary hard drive (256GB SSD) and trying to boot yet. Will report back when I do.

 

In the mean time, any helpful suggestion on how to troubleshoot things further?

 

Many thanks.

 

 

twenty
Blue Screen Again
Posts: 2
Registered: ‎12-10-2014
Location: London
Views: 2,141
Message 2 of 11

Re: W520 infinite reboot loop even before BIOS screen

Update: I've eliminated the HDD and RAM as an issue. When I took out both the HDD, same thing. When I took out the RAM, there's a loud beep from the BIOS (beep, beepx3, beep, beepx3) suggesting the BIOS can't find the RAM?

Putting things back together takes me back to square one, the reboot loop!
jal66
Ctrl-Alt-Del
Posts: 15
Registered: ‎05-31-2011
Location: DE
Views: 1,432
Message 3 of 11

Re: W520 infinite reboot loop even before BIOS screen

This reply is a bit late: try to remove the BIOS battery (small coin-size battery). It's located under the keyboard - see the hardware maintenance manual if in doubt. Remove it for some minutes without power supply or main battery attached.

Fourty
Paper Tape
Posts: 4
Registered: ‎07-20-2019
Location: GB
Views: 271
Message 4 of 11

Re: W520 infinite reboot loop even before BIOS screen

Hi,
I’ve got the exact same issue. Did you ever manage to find the root cause?
Fourty
Paper Tape
Posts: 4
Registered: ‎07-20-2019
Location: GB
Views: 271
Message 5 of 11

Re: W520 infinite reboot loop even before BIOS screen

Hi,
I’ve done it without any success. Any other options?
Community SeniorMod
Community SeniorMod
Posts: 9,868
Registered: ‎01-01-2010
Location: US
Views: 242
Message 6 of 11

Re: W520 infinite reboot loop even before BIOS screen

If you have 2 DIMMs try them one at a time.  If you only have 1, can you get another stick to try


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.
Fourty
Paper Tape
Posts: 4
Registered: ‎07-20-2019
Location: GB
Views: 235
Message 7 of 11

Re: W520 infinite reboot loop even before BIOS screen

Thank you for your suggestion. I did try RAM swapping. Still no joy!
Douglas77
Paper Tape
Posts: 5
Registered: ‎03-16-2017
Location: CA
Views: 199
Message 8 of 11

Re: W520 infinite reboot loop even before BIOS screen

w520 i was wondering if you ever found a solution to infinite  restart loop....i should have never changed bios numerical  control...that cause this loop now i cant access bios ,,tried everything,,,did you find a solution?

Douglas77
Paper Tape
Posts: 5
Registered: ‎03-16-2017
Location: CA
Views: 196
Message 9 of 11

Re: W520 infinite reboot loop even before BIOS screen

i was wondering if you found a solution to reboot infinite loop...for w520...when i was in bios i changed numerical control and this cause dthe loop issue,,,i have taken out ram and hardrive,,..tried boot cd but that did not work i dont know what to do,,it is stuck in black screen restart mode,,,,did you find a solution?  I used to think ibm thinkpad was the best but after lenova took over their software is crap and so is the hardware,,but i have a few w520,,i like the keyboard layout so i keep them as work horses,,,could you please help me thanks Doug  here is my email   douglasfurlong@rocketmail.ca

Fourty
Paper Tape
Posts: 4
Registered: ‎07-20-2019
Location: GB
Views: 166
Message 10 of 11

Re: W520 infinite reboot loop even before BIOS screen

I haven't found a solution yet. I even took out the bios battery. Interesting that you mention changing the bios before the trouble started, maybe in your case a bios reset will fix things. 

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