Power to base dies after 3-4 seconds after power is applied

Phone says "No Power to Base".. I unplug power connector from the base wait a second and replug in..The red LED turns on, within 2 seconds gets a little brighter for 1 second then totally dead.. I have checked power supply (5v) with a 5v source and same result..Cable isn't the problem because it's not intermittent. Same results consistently. the excess light before it goes dead , I'm thinking is a capacitor discharge, possibly through a hot shorted transistor.. Any thoughts out there?