DIAGNOSIS The opener lost its programming and defaulted to alarm mode. It thinks it's been tampered with.
FIX Press and hold the black program button on the logic board for 10 seconds. Release when the LED turns off. Wait 30 seconds. The LED will glow solid green. Reprogram your remotes and wall console by pressing the learn button once for each device.
IF THAT DIDN'T WORK Check the battery backup unit if equipped. A completely dead backup battery can cause a system fault. Unplug the battery connector from the logic board, then restore power to the opener to see if the beeping stops.
HEADS UP The travel limits are stored in non-volatile memory and should survive a power outage. You should not need to re-set them.