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Paper Tape
Posts: 4
Registered: ‎11-06-2015
Location: PT
Views: 194
Message 1 of 2

t520 sudden restarts

My T520 has started to exhibit a very weird behaviour: after a few minutes turned on it just suddenly restarts. After that sometimes it goes up correctly but most of the times the power button turns on for 0.5 seconds and then turns off again and it turns on again after 3 seconds and turns off after 0.5 seconds never booting up. I have to remove all battery and ac power and wait a bit to turn it on.


Sometimes it stays on for a few minutes, sometimes for 1 hour... 


The restart seems to be hardware related because I can also get the restarts when I was browsing the BIOS normally, so it doesn't seem to be software, windows or virus related.


2 months ago I opened open the laptop and changed the thermal paste of the CPU and GPU and temperatures lowered down quite a lot. 1 month ago the fingerprint reader stopped working so I opened the laptop again to disconnect it. 


I tried only using battery power and it's the same. I tried removing the battery and only using A/C power and it's the same. I ran lenovo memory tests and it came back OK.


Right now I'm lost on what can I try or what can be wrong with this. Any tips what may be wrong?  should I change the motherboard or cpu or what?

Community SeniorMod
Community SeniorMod
Posts: 12,151
Registered: ‎06-06-2011
Location: RU
Views: 189
Message 2 of 2

Re: t520 sudden restarts


The dust on the PCB elements and lanes might cause such issue. Mainly on the CPU power circuits (power filters like capacitors) near to the CPU placement and power switch chip and it circuits near to the systemboard power connector.

Clear the PCB using compressed air and alcohol.

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