Weird MacBook Pro powering sequence...WT?

[Mr Gleeman]

Hi all, new to this forum but would dearly appreciate your input

Here is my scenario:

As I like to dabble in electronics and having done basic pc repairs in the past amongst many other projects I decide to take on the challenge with a "liquid damaged" MacBook Pro 15" Model A1126 Board No 820-2915-A (early 2011) from eBay.

A bit of wine through the back end of the Mac fan(s) side, luckily minor corrosion on the logic board and nothing fried that I could see shorting out some caps and some other components stopped it from power up etc. A thorough isopropyl clean-up of a removed logic board and then reinstalled took care of that, and of course the moment of truth

Connect magsafe and all of a sudden this thing fires up and goes into OS!?
Ok, press button to turn off......nothing?.....hold power button down to turn off.......nothing? huh? WT?

So take off base plate and access battery pack disconnect battery plug from board and the computer will still run if magsafe is still plugged in. Disconnect magsafe and this is the only way it will shut down other than your normal OS Mac "shut down" (P.S will also run happily from battery pack with magsafe not connected once initially started)

Before anyone says did you reset this, hold down that or simultaneously hold all these keys for a reset for whatever..........trust me I have done the lot with no luck.

This is a logic board power issue for sure, but its got me baffled and I would really appreciate some help from an expert who might have experience with a similar problem like this before

Any suggestion on where I start looking?

Thanks in advance,

John

 

[triplelucky]

If you stop it by removing the battery connector, then reconnect the fully charged battery only ,without magsafe attached, and hit the power button does it turn on?

 

[Cristian .b]

Maybe the SMC is somehow shorted. My plastic MacBook behaved like that because the SMC chip was covered in corrosion.

 

[triplelucky]

It’s “normal” for that board to power up when the magsafe is applied with the battery connector removed or after it has been removed.

 

[Mr Gleeman]

If you stop it by removing the battery connector, then reconnect the fully charged battery only ,without magsafe attached, and hit the power button does it turn on?

No

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Maybe the SMC is somehow shorted. My plastic MacBook behaved like that because the SMC chip was covered in corrosion.

So did you end up fixing SMC and resolving this issue?

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It’s “normal” for that board to power up when the magsafe is applied with the battery connector removed or after it has been removed.

Somehow when Apple designed this board I don't think is was suppose to be a "normal" part of powering up as one of there features?

 

[triplelucky]

So far it will start up and run when you connect the magsafe, but it won’t shut down from the power button.

If you try to start with just battery, no response from the power button.

So the logical and easiest place to start troubleshooting is to rule out a bad power button and to make sure that the keyboard ribbon cable is properly seated in the connector on the logic board.