820-00163-A Chimes No Video

[javier_herart]

Hello!

Macbook Pro Retina 2015

My first time with this 00163 board. No signs of corrosion/liquid damage.

The computer turns on, chimes and no video. NO Bloq Mayus acitivity. No video on HDMI port. No video on thunderbolt.
I have flashed a new bios and the problem persisted.
I reflowed U8400 with my reballing station and same problem. No change.
What should I measure?

 

[javier_herart]

Hello.

How can check USB activity? USB keyboard?

Should I try to reball the GPU or go directly to change it?

Thanks

 

[2informaticos]

Read how to properly check USB activity.
Take notes about other tips too...

HOW TO collection

I hope this "How to" collection will help our members. I will possibly modify this post in time, if updates available. Trigger SMC_ONOFF_L (PMU_ONOFF_L): It reffers to simulate power button function, when the keyboard is not connected. We need to do this when we work with the board...

boards.rossmanngroup.com

 

[javier_herart]

Hello!

I couldnt detect any USB activity, I tried to start on safe mode with its keyboard and with an USB keboard and nothing happened.

I reballed U8400 but I have the same issue, turns on, chimes but no video.
Tried safe mode and nothing happened.

Is there anything else I could measure before replacing U8400?

Is there any supplier that you could recomend for this chip? I found this on aliexpress:
https://es.aliexpress.com/item/3291...766f6452-0&pdp_ext_f={"sku_id":"66655332724"}

Thanks!

 

[javier_herart]

Another question...

Should I try another bios file? I tried with one downloaded from Vinafix.

 

[2informaticos]

Try this, just in case.

820-00163 clean ME fixed SSN.bin

drive.google.com

Shouldn't be BIOS issue.

Don't waste time with vinafix BIOSes in the future...

 

[javier_herart]

Hello.
I just received the "new" GPU, replaced it and now the board has video (I can see the folder) but looks bad. (See attached)

Could it be bad soldering? Or bad GPU?

 

[2informaticos]

Both cases possible.
Could also be vRAM problem...

 

[javier_herart]

Any suggestion?

 

[2informaticos]

If there is Samsung vRAM, possibly damaged in rework process.
As the GPU was bought in Aliexpress can also be junk.
You can try to resolder it, just in case...