Author Topic: [RESOLVED] (it was the CPU): Dead ThinkPad CPU?  (Read 4483 times)

0 Members and 1 Guest are viewing this topic.

Offline lezginka_kabardinkaTopic starter

  • Regular Contributor
  • *
  • !
  • Posts: 84
  • Country: ru
[RESOLVED] (it was the CPU): Dead ThinkPad CPU?
« on: December 15, 2023, 06:13:03 pm »
[RESOLVED] (it was the CPU)


Thanks to all for the input, I solved this by Occam's razor logic, and going by what a ThinkPad expert had told me, elsewhere (and what sounded counter-intuitive to me) - "Try the CPU first" - yep, it went pop like a blown light bulb; can you Adam and Eve it!

Got a ThinkPad L540, had it running for 9 months. The other day as I was using it, the screen froze and I held down the power to restart it... and BLACK SCREEN!

Have checked/tested:

~ LVDS (video ribbon cable to LCD) is fine
~ RAM modules are fine (have also tested with OTHER "known good" RAM from my main laptop)

It turns on, and if I remove RAM altogether, I get the (expected) 1-3-3-1 beep sequence which indicates "Hey! What's up? NO RAM?" etc. So it is doing SOME portion of the "POST" ("Power On Self-Test") sequence.

i5-4210m is the CPU, have ordered a spare one from eBay.


Any help (apart from "bake the motherboard in the oven to reflow" type comments) would be most graciously appreciated, thanks!
« Last Edit: December 20, 2023, 11:54:38 pm by lezginka_kabardinka »
 

Offline lezginka_kabardinkaTopic starter

  • Regular Contributor
  • *
  • !
  • Posts: 84
  • Country: ru
Re: Dead ThinkPad CPU?
« Reply #1 on: December 19, 2023, 04:48:49 pm »
No one at all?
 

Offline Peabody

  • Super Contributor
  • ***
  • Posts: 2092
  • Country: us
Re: Dead ThinkPad CPU?
« Reply #2 on: December 19, 2023, 05:14:47 pm »
Is it possible it's just the display back-light burned out?  If you shine a flashlight on the display up close, can you see any indication that it's trying to display something?

Have you tried connecting an external monitor?
 

Offline lezginka_kabardinkaTopic starter

  • Regular Contributor
  • *
  • !
  • Posts: 84
  • Country: ru
Re: Dead ThinkPad CPU?
« Reply #3 on: December 19, 2023, 06:05:58 pm »
Is it possible it's just the display back-light burned out?  If you shine a flashlight on the display up close, can you see any indication that it's trying to display something?

Have you tried connecting an external monitor?

~ No video detected (meant to mention that in initial post) - shone flashlight and another ring light, NADA.
~ No go with VGA out; tested on a TV and an external monitor.

Thanks
 

Offline jmelson

  • Super Contributor
  • ***
  • Posts: 2796
  • Country: us
Re: Dead ThinkPad CPU?
« Reply #4 on: December 19, 2023, 06:21:34 pm »
Does it have a spinning hard drive?  If so, can you hear the drive seek during the boot sequence?  If so, it is likely a graphics issue, and could even be a software issue where the windowing system fails to start.  If SSD, then does the disk activity light flash?
Jon
 

Offline Halcyon

  • Global Moderator
  • *****
  • Posts: 5775
  • Country: au
Re: Dead ThinkPad CPU?
« Reply #5 on: December 20, 2023, 01:21:27 am »
It could be any number of things.

It's not impossible, but CPUs are extremely unlikely to fail. Aside from the days of the poorly designed AMD CPU's, I've never had a CPU just stop working in over 25 years.

In rough orders of most likely to less likely, I would suggest:

- Manifestation due to pre-existing damage (due to liquid or foreign matter ingress, exposure to extreme temperatures, mechanical damage...)
- Corrupt firmware (although Lenovo's self-healing BIOS should take care of this)
- Power supply or power regulation issue
- Problem with the GPU or display circuitry
- Fault with the motherboard or bad solder joint
- Fault with the CPU
 
The following users thanked this post: lezginka_kabardinka

Offline lezginka_kabardinkaTopic starter

  • Regular Contributor
  • *
  • !
  • Posts: 84
  • Country: ru
Re: [RESOLVED] (it was the CPU): Dead ThinkPad CPU?
« Reply #6 on: December 20, 2023, 11:54:45 pm »
[RESOLVED] (it was the CPU)


Thanks to all for the input, I solved this by Occam's razor logic, and going by what a ThinkPad expert had told me, elsewhere (and what sounded counter-intuitive to me) - "Try the CPU first" - yep, it went pop like a blown light bulb; can you Adam and Eve it!
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf