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macrumors newbie
Original poster
Dec 10, 2013
Hi. I have a 2009 Macbook Unibody with a faulty SMC. I have tried resetting it and the NVRAM with no results. Currently, the battery is out, and the fans are on high speed. On every boot up, it forgets the time and wireless settings (of course). To get it to turn on though, I must unplug the charger, clear all the capacitors by holding the power button for a second or two, release the power button, replug the power cable, hold the power button for 10 seconds, release the power button, wait 5 seconds, and then press the power button once. This is the only way I can turn the Macbook on. If I try this method and hold down [L-SHIFT]+[OPTION]+[COMMAND], it forces a power off override (I can't force reset the SMC). I was looking for a software method in the terminal, but no luck there. I have ran the diagnostics (hold down [D] on boot), and everything passes.

Boot ROM Version: MB6.100C8.B00
SMC Version (system): 1.51f53

This is the main/motherboard [MB] here to prevent confusion:

I have re-flowed the SMC with a hot air gun (for newcomers, you can see the SMC above the GPU) as a resort to thinking there must be a cracked BGA ball. Doesn't look like that was the problem. I reckon there is a pull-up resistor or something that has fried. I noticed that this started happening when one day I plugged my mag safe (power) connector into the Macbook and saw a little spark whilst plugging it in. If that caused any problems or not, I'm not sure. I doubt it though.

Schematics would be appreciated so I can fault find as I have an oscilloscope.

The SMC sucks. EEPROM BIOS's rule.

Thanks for your help and time.
Last edited:


Staff member
May 3, 2009
as old-wiz stated they're proprietary and such we requests for schematics are not permitted.
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