The power button is only a momentary on switch that signals the CPU to wake up or go to sleep. If you couldn't turn it on or off, then I would say it is the switch. However you say you cannot turn it on but you can turn it off. That may mean another problem within the control board's digital logic (ie - contact and send back to FM). I know of no official way to do a hard reboot of the OW. Perhaps press on the power button and hold it for 15 - 30 seconds to see if that does anything?
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