Well I figured it out for myself. The problem was the light socket not the switch. The ground terminal of the lamp socket mashed to a position that it was not making good contact with the lamp. The fix was to bend the ground terminal outward a small amount such that good contact was made. Light now the light works and the testing across the switch wires reads 120 volts; I guess the previous 50 volt measurement was due to high resistance of poor contact.