Sounds like you may have a loose connection inside the VHF or, more likely; corrosion in the wires making the connection to your wiring harness. Try disconnecting the radio, cleaning the connections with sandpaper and reconnecting the radio. If that doesn't work, its probably internal and you'll probably have to replace the unit.
Nope. Took it apart, and power is getting to the circuit board. Everything is clean. Wiggled connections, and nothing. Strange. Oh well, time too go shopping!