Hello Ben....as u see below, there are two different SMC resets. It depends on wether u have a removable battery or not.
Reset the SMC of a MacBook or MacBook Pro’s with detachable batteries:
- Shutdown the MacBook/Pro and remove the battery
- Disconnect the power adapter, hold the Power Key for 10 seconds
- Release the power key and reconnect your battery and power adapter
- Turn your Mac on
- Let boot as usual.
Reset SMC of a MacBook or MacBook Pro’s with an internal battery:
- Shutdown your MacBook/Pro
- Connect the power adapter to your Mac
- On the MacBook/Pro’s keyboard, hold down the Shift+Control+Option keys and the Power button at the same time
- Release all keys and the power button at the same time
- Boot your Mac as usual
Make sure that you are performing the correct SMC for your machine. If this doesn't work; I would create a new user account and see if the problem persists, before jumping into a repair. If this doesn't help; you might need to replace the I/O Board of your machine.