820-2850-A GPU issue

[protocold]

820-2850-A with garbaged screen. It chimes and mouse works.

I created a linux usb with grub with these command:
outb 0x728 1
outb 0x710 2
outb 0x740 2
outb 0x750 0

and it went to a black screen and then shortly the screen is ok and allow me to boot up ubuntu graphic mode.. so the internal intel video works.

what should I do?

 

[piernov]

820-2850? 820-2915?

 

[2informaticos]

If is 2850, change C9560 first...

 

[protocold]

2850, already changed C9560.

I have just tried to set the nvram gpu-power-prefs and it behaves like 2915 that the garbage screen is gone and I saw white screen with flashing folder (i have no hdd installed).

So I guess this should confirmed that the mux is no problem but a bad GPU?

 

[2informaticos]

Should be GPU then.
A hardware mod to disable it is already posted on the forum, I suppose.

 

[protocold]

you mean remove R8911?

I actually tried to remove this before without the nvam var and the fan will start and stop cycling.

Now that I have the nvram in place, let me try it again.

 

[protocold]

Also, it seems like the left speakers (the small one with the mic attached) doesnt work.. the chime sound came from the right speaker (attached together with subwoofer)

DZ6706 and C6705 are missing..are they critical for the headphone?

where do i start on this one?

 

[2informaticos]

Disabling GPU power supply is not sufficient; aka removing R8904/11.

820-2850 A1286 - 2010 Conversion.rar

drive.google.com

Is already posted on some thread...

 

[protocold]

why would removing R8904/11 in 820-2850 causes the fans to spin up and down in cycle but the same is unaffected in 820-2915?

 

[2informaticos]

Nobody mentioned this behaviour until now.
And I think few people did this mod on the forum.

Run HWMonitor and look for any strange temp.
Maybe GPU temp sensor is affected, when its power supply is stopped.

 

[protocold]

HWMonitor cannot be run, as the 820-2850 will not boot up at all, fan just keep on spinning up and down. If you look into the mod files that you shared, you can find that the is no mention of cutting the GPU power, only soldering the lvds wires and backlight enable pins.

It seems like the GPU power wasnt cut. Was this done in some other way?

 

[2informaticos]

I never dealt with GPU disable on 2850...