820-00163-A Chimes No Video

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?

First of all, welcome to the forum!

Looks like your board gets blocked after chimes, because failing communication between CPU and GPU.
You should have a bad GPU there; need to change it.

Any sign of USB activity?
Just in case, try to start in safe mode.

Hello.

How can check USB activity? USB keyboard?

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

Thanks

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

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!

Another question...

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

Try this, just in case.
Shouldn't be BIOS issue.

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

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?

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

Any suggestion?

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...