2011 MBP - 820-2936-A - AHT Error

[katfish]

A little background ... battery swollen to the point of pushing the touchpad up. Computer powers on, start the boot, shows an Apple logo and the spinning wheel. Left sitting for a while, the wheel is still spinning. Pulled the hard drive and ran a diag on it, passes ok.

Boot into AHT ... quick test result 4SNS - VDOR. I understand this is Voltage DC Circuit. I don't see many MBP's wander into my shop. Any pointers on what to look for?

I checked out the current sensing resistors, all seems fine there. ISL problem maybe?? Or should I be looking for something else? I'm guessing because of the sensor error, this thing is now running in a reduced performance state. But even after an hour, it still hadn't loaded the login/desktop. Just a spinning wheel. With or without the battery connected.

Chuck

[katfish]

Re: 2011 MBP - 820-2936-A - AHT Error

SMC is flat on the board.... that's not normal is it??

Doesn't appear to have been replaced. If so, was a nice clean job. However, I don't see these all that often, but I don't recall seeing an SMC flat on the board before. Under the scope, there is no gap, no balls to be seen.

I've checked out all of the sensing related circuits ... everything seems to point back to SMC. So I was checking it out under the scope.

[katfish]

Re: 2011 MBP - 820-2936-A - AHT Error

Pulled SMC, reballed .... still same error with AHT.

4SNS/1/40000000: VD0R-18.625

[katfish]

Re: 2011 MBP - 820-2936-A - AHT Error

Still no idea what this error indicates.

Went ahead and pulled the SMC, reballed ok.

Found corrupt file system on hdd. Scrubbed and install OSX ok. Boots and runs fine now. Replaced battery as well.