HP Elitebook 840 G3 motherboard faulty?

[Nurble77]

Hi,

I bought a used HP Elitebook 840 G3 on ebay. It came as untested, without a Hard Drive.
When I first started it, it gave me a series of POST beeps - 2.2, followed by 3.2. I identified the beeps as corrupted bios and faulty ram. I replaced the ram and the beeps stopped. Now when I turned it on, the keyboard backlight went on for a moment, then turned off, followed by the laptop turning itself off shortly after.
I created a bios recovery flash drive, using an HP setup file, popped it in and started it, while keeping windows+b pressed, the method outlined here
The laptop now stayed on, the fan started running, but nothing else happened. The USB drive blinked for a second when I turned the laptop on.
I left it like this for several hours (apparently flashing the bios can take up to 40 minutes) but still, no change. The screen backlight went on, but the screens remained black and nothing else happened.
I changed the cmos battery, tried resetting the cmos, nothing happened.

I'm guessing the motherboard has a fault somewhere, but that's really where my expertise ends. I have no idea how to even check the motherboard for faults, or where I should look. I'm willing to learn, but if someone could point me in the right direction, I'd very much appreciate it. Or it could be something else entirely?

[techtiger]

you have to Dissemble the laptop and removed bios chip With the special tool you have to flash working bin

[Nurble77]

Originally Posted by techtiger

you have to Dissemble the laptop and removed bios chip With the special tool you have to flash working bin

Would you mind telling me what "special tool" you are referring to?

[techtiger]

Try eBay EZP2019/20 Flash Bios tool or CH341A With the accessories

[Nurble77]

So you don't think the Motherboard is faulty somewhere?

[caspian]

It is possible that the mainboard be faulty. But to make sure, the first step is reprogramming Bios.
But as you did not reprogram Bios properly, @techtiger recommended you desolder the Bios chip and use an external programmer. This is my recommendation too.
If no result, then you can continue testing the mainboard further.
Does the CPU get warm?

[Nurble77]

Originally Posted by caspian

It is possible that the mainboard be faulty. But to make sure, the first step is reprogramming Bios.
But as you did not reprogram Bios properly, @techtiger recommended you desolder the Bios chip and use an external programmer. This is my recommendation too.
If no result, then you can continue testing the mainboard further.
Does the CPU get warm?

I tried to flash the bios the way HP recommended... I didn't know about external programmers. But I'll try it!

The CPU doesn't get warm at all. The fan spins and I guess thermal paste should hold for 4 years (the manufacture date of the laptop is August 2016). But as I'm going to take it apart anyways, I will replace the thermal paste.

I know a few things about taking computers apart, i just don't know about replacing/checking parts on the motherboard itself.

[caspian]

If the CPU doesn't get warm, that means the mainboard is faulty. Bios reprogramming is not required anymore.

[Nurble77]

Originally Posted by caspian

If the CPU doesn't get warm, that means the mainboard is faulty. Bios reprogramming is not required anymore.

How do you figure that?

[caspian]

because that means the mainboard does not provide any power to the CPU.

[Nurble77]

Just tested it, took the fan off, started it, the cpu got hot within seconds.

I also saw that the light on the SDD was on (I got a new M.2 and put it in). But since the Disk is blank, I guess that only means that the SSD is receiving power?

[caspian]

yes,
If the CPU gets warm, you can reprogram Bios. To learn how to do that using an external programmer, search the net for guide pages and videos.

[Nurble77]

I've already found a number of youtube videos in the subject

Just to clarify, this would do the trick, right? All of the EZP tools I found ship from China and take 6-8 weeks to deliver. But this one has a badly translated description.

[caspian]

I do not have any experience with that programmer. Let other members share their experiences.
All SPI programmers are OK to use for programming Bios in laptops. In addition, you must buy an adapter to hold the SPI IC which is constructed as a SOIC8 IC .
There exist a number of threads in this forum related to buying a new programmer. please have a look at them.

[SMDFlea]

Is your bios chip a sop8 or WSON

[Nurble77]

Originally Posted by caspian

I do not have any experience with that programmer. Let other members share their experiences.
All SPI programmers are OK to use for programming Bios in laptops. In addition, you must buy an adapter to hold the SPI IC which is constructed as a SOIC8 IC .
There exist a number of threads in this forum related to buying a new programmer. please have a look at them.

All right I will have a look in the forum. Thanks you very much for your help!

[Nurble77]

Originally Posted by SMDFlea

Is your bios chip a sop8 or WSON

Um... There's two, but I can't really make out the writing on them, they're too small... both winbond, I think one of them says 25q64fv10 and the other 25q128vfq, but google doesn't know those parts numbers, so I could be mistaken.
This is the best picture I could take.

[peterzz2007]

Hello all,
i`v got the same problem as mentioned on first article in this thread.
I tried some other BIOS files downloaded from this site,but it`s even worse-USB drive is not accessed at all and CPU is cold.
With old BIOS USB drive LED is flashing shortly,then is allways on,CPU is warm.
Thank you on advance!