There is likely a voltage regulator or a diode burned out in the vicinity of the power supply. If you have the schematic, start at the power supply and work through the circuit to the I.C. Also look up the pinout on the internet for that I.C. With the power on test the voltages at each pin on the I.C. You should not have supply voltage readings on any of the signal pins. This is an indication that the I.C. is also burned out. Use a volt ohm meter with a D.C. voltage setting. Also hopefully your meter should have a diode test function. If not you can still test them with the resistance test function.Here is a link to an explanation:http://www.elexp.com/t_test.htm I hope this helps.