Do you have a voltmeter of some kind? The voltage regulator is the black chip on the lower left hand side of the board with three pins and a screw in it. the top pin should be about 9v, the middle pin is ground (0 volts), and the bottom pin should be about 5 volts. You read the voltage by using the two test clips on the voltmeter. Make sure it is set for DC voltage. Put the black test clip to the Ground (0 volts), I usually use the Rf modulator case. Then put the red test clip to the top and bottom pin of the regulator to test each of them and see if you get the proper reading for both of them. I would also do the same with the power switch and jack. same thing, black test clip to Ground and red to the switch/jack, see if you are getting 9v for that as well.