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Modello inizio 2011, A1278 / processore i5 2,3 GHz o i7 2,7 GHz

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MacBook Pro chime + no Video + Board is getting very hot

Hello Again,

i was wondering if any of you guys have encountered this problem before.

Ive got a Macbook Pro 2011 13” which has been water damaged. There were no obvious signs of corrosion. I had a green light but it was not turning on.

1. I found out i had a short on PPBUS. More prezise PPBUS_S5_HS. Found the short on Q7550 and replaced it.

That kind of fixed it. Now i have fan spin. Looks like it is working.

2. But when i tried it the first time i had no chime and artifacts on the screen.

Block Image

I reset the SMC and rebooted. Now I have fan spin and a chime. BUT no backlight + no video at all.

I tried to reset the PRAM/NVRAM but that is not working at all?!

The board is getting very very hot.

I think there might be another short on the CPU that caused the Q7550 to fail in the first place.

But I would like to be wrong and some one has another explanation.

Do i miss something? How should i proceed?

Battery is new.

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All the Power rails seem to be good. the only one that looks odd is the firewire PPCP_FW line it is 13.6V instead of 12.8V.

da

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I don’t have a hard-and-fast answer to your question, but I may be able to help you.

I use a product called “Freeze Spray” which is FANTASTIC stuff, and saves me endless hours fault-finding.

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Basically you remove power from the board you are diagnosing, and spray a suspect area with the freeze spray. Give it a bit to cool down and frost over, and then apply power to the board. As soon as you apply power, any shorted components will heat up very quickly, and will cause the area to ‘defrost’ from an obviously identifiable location, allowing you to very quickly identify shorted components. (It is ‘nice’ if you can use a current limited power supply, but this isn’t always possible.)

There are plenty of how-to type videos on YouTube if you want to see what this process should look like.

Also, if you are doing water damage repairs and you do not have an ultrasonic cleaner, get one. They are a necessity for any water damage repairs. You can get cheap ones to get you started, but if you can, move up to a Crest CP500HT. What an ultrasonic cleaner does is clean your circuit board, but it gets underneath chips, BGAs, and other places you otherwise couldn’t. Many of the water damage repairs I have done went from a brick to booting up simply after a couple of minutes in the ultrasonic cleaner.

I hope this isn’t “preaching to the choir”! And I wish you good luck with the repair.

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if you have water damaged mother board then u might fix a certain area then u will follow with more issues after if ur liquid has dried up.

that looks like gpu issue.

try re heating the chip.

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7 Commenti:

OP: Don't reflow the chip, this won't fix the problem.

The problem most likely arises from the GPU getting shorted most likely I would check the power rails for GPU like explained here:

https://www.rossmanngroup.com/boards/for...

da

Tanks for the Answers. Right know its not even chiming anymore.

I will try that after i replaced the Mosfets + the mosfet controller ic. I am waiting for the spareparts but i will let you know.

I thought its maybe this.

https://www.youtube.com/watch?v=iot4lO1N...

da

Update I replaced the Mostes and Controller am back to where I started.

Fan spins I get a chime but no image.

I will try the GPU power lines now

da

This Model is working just with the internal Graphics Intel HD Graphics 3000.

da

@niklasjakob Do you see anything when you plug it into an external display?

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Niklas Jakob sarà eternamente grato.
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