Assuming you have the "A" model, and assuming you are sure you are using a charged replaceable battery pack, your Maestro may have to go back to Flex, but I suggest submitting a trouble report to get confirmation.
Maybe there should be a notice on the back of the maestro like,
Maestro charger connected at all times when not in use to avoid
When not using the maestro you need to keep the internal battery charged or the battery volts will drop to a point where the maestro will not start up.
Following Dudley's direction :
- I plugged-in the external power supply (confirming that the green LED on the 'brick' was glowing) and then held-down the Maestro's Power Button for 60 seconds (Dudley had said "30 or 40 seconds" but I figured that 'a little more can't hurt')
- leaving the Maestro plugged into the external power supply I set it aside (as Dudley had said to then leave it alone for 24 hours with the external PS connected)
- about 5 minutes later, out of the corner of my eye (since I'd set the Maestro to the side), I caught a flicker (I thought at first it was either my imagination or a reflection off something)
- I looked at the Maestro unit and its screen had come on showing the WiFi Network search screen (no EtherNet cable was plugged in).
Since then my Maestro has 'played' like it should (and I'm going to leave it plugged-in for the next 24 hours to give the internal battery a chance to recharge).
Dudley had explained that there needs to be a slight amount of charge remaining in the internal battery (not what a user can install inside the rear battery compartment but the internal battery which we can't access) for the Maestro to be able to boot-up. Dudley said that from what he's seen there is about a 50/50 chance that holding down the Power Button for an extended period of time, and then waiting 24 hours with the Maestro plugged into the external power source, will get the Maestro to power up (and then allow the internal battery to recharge). I was surprised (but pleased of cource) when my Maestro decided to 'wake-up' after only a few minutes.