0

Score

Avatar
scottgriz
43

Asked

Does anyone have knowledge of component level logic board repair?

History

I'm trying to revive a 2.4Ghz Unibody Macbook which I bought on ebay. It was advertised as having sustained liquid damage. So far I've been successful in repairing two with top case replacements and was hoping for a third. The fact that the green power light was showing on the adapter was a positive sign.

So here is what I have done. I have disassembled the mac and removed the logic board prior to attempting to apply any power to it. I brushed the board lightly with some 91% Isopropyl to remove any residue.

With the logic board out and only the fan connected and AC power connected, I shorted the power pads on the board to see if the fan would spin up. No dice.

I do know that this is possible as I am typing this on another Macbook which I did the same thing with and it worked. (And before anyone panics, yes I know that I should not leave it running like this due to heat. I test it for about 5 seconds.)

I just disassembled this mac to pull the known working DC in board from it to test with the bum logic board. Still no dice. I then put the suspect DC in on this known working logic board and was able to get the fan to spin up.

So, now I have eliminated the DC in board and isolated the top case from the equation. I always test the board without the top case connected since it is usually problematic after spill damage.

The adapter I am using to test works and I now seem to be out of options other than looking at the board at a component level.

So does anyone have experience they can share regarding where to start on a board and how to test parts?

Are there any board level repairs that can be done without extensive knowledge and equipment. I'm fairly savvy when it comes to completing most part replacement repairs and assessing problems, but when it comes to logic boards, that's about my limit. But, that said, I'd love to learn.

Thanks to anyone who can provide help. It will be greatly appreciated.

-Scott

I had the same problem than you with exactly the same machine two months ago. Liquid spilled machine, steady green light on the magsafe but no activity. Could not find out the issue so I sent the board to a Peterborough (Canada) electronic shop for repair. They were unable to repair (logic board was shorted internally). Bought an used A1342 2.26ghz replacement logic board on ebay for a fair price. the 2.26ghz board is compatible with the 2.4ghz case so if you find a good deal go for it. Good luck !!

lemerise,

Post Answer

1

Score

Avatar
WakiTech
349

Answered

PermalinkHistory

your testing and assessing is right, pls check carefully your logic board if there is a corrosion, must be disassemble completely so you can check also the other side. let me know the answer.

I have the board completely out and have cleaned both sides of it with alcohol. There is no visible damage that I can see. What I am looking for is any information relating to measurable voltages at specific points on the board so I can narrow down the potential component. I am not interested in buying a working board or sending it out for someone else to work on. My goal is to repair it and resell it for more than I paid. I do not need it as I already have one. Thanks for the help.

scottgriz,

@ Wakitech You have given freely of your above average experience/advice and have much to offer. I hope all is well in your world and that you will continue to contribute to this community.

ABCellars,

Add Your Answer

View Statistics:

Today: 0

This Week: 2

This Month: 8

All Time: 1,073