I have a 820-3437 with no power button. The unit powers on when the charger is connected with the battery plugged in, light goes amber, fan spins and stops 3 times then the system powers up and works as expected. I cannot turn it off or on using the power button. I disconnected the IPD Flex and shorted SMC_ONOFF_L to ground but it still doesn't work. I am lost here as the circuit doesn't have alot of components but I still can't find the fault. Any help would be appreciated.