HP G62 Notebook shuts off randomly after 20-30 seconds work

[Rumbarov]

My HP G62 Notebook has recently started to shut off randomly about 20-30 seconds after power on. I have had it for 3 and a half years now. There is no sound and the computer shuts off. The same happens when only on battery or only on power adaptor.

The fan is working normaly (starts on full speed and reduce the speed to normal). I cleaned the fan paths, changed the CPU thermal grease. Changed the thermal pads of North and Sout bridge and GPU. No result.
So i do not believe that overheating is causing my computer to shut off. So far i have no other ideas what to check. If somebody can help, please you are wellcome.
Thanks in advance.

[BHK6]

Hi @Rumbarov

Welcome to the HP Community! I see that you are having a problem getting your notebook to stay on for longer then 30 seconds. Let me start by getting some additional information. What operating system are you using? What is your product number so I know what we are working with?

You are right that it doesn't sound like an overheating issue as it shouldn't be getting hot enough to shutdown the notebook in 30 seconds. Have you gotten any error messages at all?

[Rumbarov]

Hi,  first of all thank you for you answer. The  laptop is HP G62 B40EQ, i bye it from STEMO - Bulgaria. Windows 7 Home premium 64 bit. The Windows start to load, but the laptop shuts of before Windows finish  loading. And no, no one error. 

[BHK6]

Hi Rumbarov

Try seeing if you can boot up in Safe Mode which will load Windows with minimum software and drivers. This will give us an indication if there is software or driver conflict that is causing this issue.

[Rumbarov]

Hi BHK6, i forgot to say that i did this. The result is the same -a bit before or a bit after the log on screen the laptop shuts of. I think it is not software problem. May be something in the haardware - especialy in thermal sensors or their control. cirquits.

[BHK6]

Hi Rumbarov,

It does sound like a hardware issue. You can test the hardware using the UEFI Diagnostic Tools as mentioned in this HP document Testing for Hardware Failures. It won't test the thermal sensors but if you run the System Test – Extensive Test it will check most of the major hardware components.

[Rumbarov]

Hi BHK6, the BIOS of the  laptop has only basic tests - memory and HDD. I dont dare to start uodate of the BIOS,  becose if during update it shuts of i will have a brick instead of laptop:( The basic tests run without errors till the shut off. Very delicate situation.  Thank you for your help. I hope i will get some new ideas and inspiration soon.

[Rumbarov]

Hi everybody,

After freezing thr laptop outside in the balcony – it was absolutely clear that the heat is not the problem. I start checking the voltages on the motherboard. One of them was strange  +VDDR_CPU is 0.94V.This voltage is the power for DRAM. The laptop has DD3 RAM on 1333Mhz bus. Documentation says that for DRAM – DDR3 on 1333 Mhz bus – the power should be 1.05V and 0.9V for DDR3 on 1066 bus. First I decide to look in the BIOS, but there is no option to select DRAM power. +VDDR_CPU is made by PU3 – NB634 to 0.9V. When +VDDR_CPU_EN get high – it makes +VDDR_CPU to 1.05V. But this not happens and the laptop shut off. This is the situation so far. I don’t know why +VDDR_CPU_EN stay low, is it from broken BIOS or something else. The work continue and I shall write if something change.

[Rumbarov]

Sorry, i made a mistake - VDDR_ADJ high changes VDDR_CPU from 0.9 to 1.05V.  It go high for a second and falls low, but why so far i can't see. 

[BHK6]

Hi Rumbarov,

You are getting into the engineering side of this if you are testing the voltage on individual parts and that is outside my area of expertise. At this point I would advise that you contact us. You can reach HP Total Care at 1-800-474-6836 in North America or start here outside of North America.