That's an option not many other people got! Check if the "Battery" light on the dash is turning off. That is is the turn-on circuit for the built-in voltage regulator. If the light is on, you have an ignition switch problem. If it is off, I suspect the voltage regulator is defective. One wire to it, (typically yellow) will have 12 volts all the time so there is a power source there if there's an internal defect.