HP 850 G1 mobo problem

[DeniS182]

Hi all,
I have a problem with this laptop. When the power button is pressed, the power led stays for 5 seconds and then turn off.

3.3V and 5V is present, 3.3V on bios chip is present. There is no RAM voltage and I mean also gpu, cpu voltage not present .. Have someone schematic for this laptop? and any idea, help? Maybe bios is corrupted. I need to desolder bios chip, backup and upload dump there.

Thanks for answer

Mobo code: 6050a2559101 - mb - a03

edit: I attached main bios dump

[Techtiger]

Re: HP 850 G1 mobo problem

Check the voltage on SIO U300 pin 74 84#

[DeniS182]

Re: HP 850 G1 mobo problem

SIO U300-
pin 74 = 3.6V
pin 84 = 3.3V

[Techtiger]

Re: HP 850 G1 mobo problem

SIO U300-
pin 74 = 3.6V
pin 84 = 3.3V

Check the voltage of this 5 pins One by one as you press the power button
Pin 85 38 81 73 4
These two pins out presses Power button Pin 31 100
Bios may be corrupted

[mcplslg123]

Re: HP 850 G1 mobo problem

+3V/5V VS line is ok??

[DeniS182]

Re: HP 850 G1 mobo problem

At first i tried flash main bios - some bin file from badcaps. Now laptop starts, stay on, no picture,no backlight, cpu Or gpu Or both is getting hot, but no voltage on RAM memory. Can someone fix my bios Or post working Dump to test? Thanks

[DeniS182]

Re: HP 850 G1 mobo problem

My problem Is in cpu itselft.. Internal gpu is very very hot after power adapter is connected

[Techtiger]

Re: HP 850 G1 mobo problem

Check the resistance to GND L6750 L6600

[DeniS182]

Re: HP 850 G1 mobo problem

L6750 -18.3ohm
L6600 - 72ohm

[KvnTM]

Re: HP 850 G1 mobo problem

My problem Is in cpu itselft.. Internal gpu is very very hot after power adapter is connected

Does the smaller die on the cpu package get hot (The die marked "PCH" on the picture)?


Or do you mean the dedicated gpu? The AMD one.

[DeniS182]

Re: HP 850 G1 mobo problem

yes smaller die get hot /PCH/

[mcplslg123]

Re: HP 850 G1 mobo problem

yes smaller die get hot /PCH/

End of story unless you want to replace the SOC chip.

[KvnTM]

Re: HP 850 G1 mobo problem

End of story unless you want to replace the SOC chip.

Yup. Just what I expected. SOC is Dead.
You'd have to replace the cpu in order to fix it. Theres no other way around.