(SOLVED) Does anyone know how to reset the SMC directly? Solved

(SOLVED - please read info below the original message)

Original message

Does anyone know how to reset the SMC directly from the MBP 2007 A1226 (820 2101-A, model of the logic board )? Is it more effective than the standard cmd-option r+p? The fans of my MBP blast full speed from the start and have not temperatures available). This could really need a proper reset. Please let me know if there's a way. Many thanks.

SOLVED (For your consideration if you're having a similar problem)

I've managed to solve my MBP 2007 santa rosa blasting fans problem. SMC reset on the board wasn't necessary. The problem was that even after resetting the SMC (the 5 seconds bypass), the machine wouldn't assume it because my battery had no charge (because my MBP wasn't charging or even detecting it). Somehow it was requiring some juice to take the SMC reset into effect.

I was lucky enough to have a spare MBP that charged my battery and then I tested it on my faulty machine.

All of the sudden, after inserting a fully charged battery (after doing the SMC bypass/reset) my machine decides to boot quietly like the blasting fans problem had never existed.

It's great to have my machine back to normal.

Would like to thank the community for the snippets of information here and there that helped solve my case.

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1 Answer

Chosen Solution

Disconnect the battery and the mag-safe adapter. Press and hold the power button for 5 seconds for the SMC. You gave directions for a PRAM reset. If you are having issues with that, remove one stick of RAM. On the first restart do the keyboard commands. This will clear even a lock.

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Hi Mayer, thanks for that but unfortunately the fans still go on max speed from boot, after your instructions.

Doing the SMC bypass (5 secs) is the only way to make my MBP 07 santa rosa start, and it doesn't recognise the battery (not too old) anymore. I even tried to do the SMC bypass with the battery on and it still doesn't recognise or charge it (tho I first di the way you instructed). The only difference is that when the battery is in place, the charger green light doesn't show up.

The temp sensors were all replaced and so was the heatsink/thermal paste, and the problem continues. Hence I though maybe there would be a direct SMC reset on the logic board that would potentially be more effective than the 5+5 secs trick. Does such think exist? I've heard it exists on previous logic boards but not sure about mine (820 2101-A model).

Any information would be great.

Many thanks


Maybe @rdklinc can help on this one.


I've never done this, but I believe there are SMC reset pads on the board, similar to the power-on pads that you would use to jump the board. It's always a challenge to find the pads on 15" aluminums, but the SMC reset should be somewhere on there. I know I've occasionally seen them as I was searching for the power-on pads.

However, an SMC reset is not going to fix this. If you're getting a fan-on-high condition immediately upon powering on, it's almost always a temperature sensor issue. The computer is not getting a reading from a particular sensor, or you're using the wrong sensors, or a sensor is bad, so it puts the fans on high as a precaution. There are also temperature sensors on the topcase/keyboard. I would try a different topcase/keyboard. If you've been swapping sensors on the board, it's possible you've gotten them mixed up, are using the wrong ones, etc.


RoadKill - @rdklinc Interestingly, I was working on a Core Duo Mac Mini last week and it had a run away fan issue. Could not figure it out. Found the speaker was disconnected, hooked it up and solved the fan issue.


@mayer that's interesting! So maybe various components can trigger the fan situation. Or maybe it was a combo fan/heat sensor? :-)


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