820-3787 with screen artefacts and boiling U2800

[phuketmymac]

Hi,

We have that very clean board without signs of liquid damage which shows artifacts on the screen, right at the EFI boot menu.
So we were suspecting a dying GPU however we realized that U2800 was boiling hot.

This chip seems to be related to the thunderbolt ports. Could it be also related to our problem? Does it worth re-balling that chip?

 

[dukefawks]

Why would reballing fix a chip that gets hot? Replace it with another one.

 

[phuketmymac]

Sorry, I meant reballing another chip from a donor board, like I would do with an SMC.

Can that chip interacts with the internal display though? (I am getting the artefacts on both LCD and screen connected to display port)

 

[dukefawks]

Follow the schematic and engage the brain, it all is very clear.

 

[phuketmymac]

I did remove that chip and still get the artefacts on the LCD screen.

That board looks very clean and I can't find any corrosion anywhere.

I don't get your message Duke, do you mean I am missing something? (since my brain won't turn on here...)

 

[dukefawks]

Can you post a picture of the distortion?

 

[Gurmon]

In schematic, you'll see u2800 doesn't have a lot to do with the internal display port.

Start from j8300 work backwards from there. There is not a lot to check.

Can you post a pick of these artifacts, im just curious ?

 

[phuketmymac]

After replacing a RAM chip, all seem to be better. Now since I have removed (stupidely) that U2800 chip, may someone advise what is the brand model of that chip?

Thanks in advance,

 

[dukefawks]

It says right on the chip DSL5520.

 

[phuketmymac]

My apologies, I must have tired at the time I did google the writings. I believe I did seach for DSL5220 instead of DSL5520.
Thank you Duke!

 

[phuketmymac]

I am bringing that post back to life.
I have kept that board for the rainy days...

I have already replaced U2800 which was mistake cause most likely it wasn't the issue.
Now I am getting no picture at all.

Luckily, I've seen Louis Live stream a few days ago and he have had a Thunderbolt issue on the same board model which U2800 was the culprit.
He said that this chip has to be reprogrammed and so taken from a donor board to be re-balled.

Can you confirm that this chip has to be reprogrammed?

 

[dukefawks]

Not sure I have never replaced one, but why take the risk and just use a donor chip.