Some times when you connect the magsafe connector the LED shines green and then slowly starts to fade. checked as many components as I can and done my best to find some kind of problem. I've stripped the Logic board out, cleaned it dried re-assembled it. The machine was working then one day it just stopped charging. I have successfully booted it now using the technique mentioned earilier in this thread. I have enabled what I think is PM on my side. If you measure 3.4V then you are one step closer to a live board. A quick way to see if you have G3Hot is to check the 2 pads near the hard drive connector that allow you to turn on the board without the keyboard button. If this power rail is dead then the board is dead. The power rail "G3Hot" gives 3.425V to the SMC and other logic prior to the rest of the rails coming up at startup. The bad news is that means I can't troubleshoot further on this particular issue until I get another board with these symptoms.īy the way, there is a quick checkpoint to tell you if the board has any chance at all. The good news (for me) is that I managed to fix my sample board by cleaning off some corrosion near the SMC on the back of the board (this was a liquid spill Macbook that I picked up off eBay). The SMC bypass just allows you to get one step ahead and troubleshoot the rest of the board. Anything that prevents the SMC from initializing would lead to the symptom of no boot. I suspect that the symptom is common for a broad range of faults. Selecting an external (instead of internal) video source for some iMac displays Responding to display lid opening and closing on portable Macs Responding to presses of the power button The System Management Controller (SMC) is responsible for many low-level functions on Intel-based Macs. Not sure at the moment why the plugging in of the magsafe while holding the power allows the system to boot. Taken from the Apple support page about resetting the SMC suggests all of these symptoms are related to non-communication with the SMC. "About this Mac" can not see the battery even though it is plugged in.Įverything else seems to work (Airport, USB, iSight, DVD, Disk) IStat menus can not sense either temperature or fan speed so access to those sensors is not there. Boots up into OSX but with a few caveats which I list below: PRESTO! The Macbook chimes and starts up but with fan on high speed. Release the power button and wait a couple of seconds. Continue to hold down the power button for 5 to 10 seconds. While continuing to hold the power button plug in the magsafe connector. With the magsafe disconnected press and hold the power button. No response to standard SMC reset procedure. The MBP will appear to be completely dead. Please feel free to add your own experiences/symptoms and hopefully we can get close to the HW solution. I suspect these are usually the result of some trauma or liquid spill that damages some aspect of the SMC control circuit. In the hopes of generating some technical sharing on this particular HW issue I am starting up a thread to share the symptoms and potential solution to what appears to be a fairly common failure mode on the Macbook Pro 13" (and possible other unibody Macbooks).
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