Attached is the schematics for the radio circuit. Get a test lamp or DVOM and test the Black/Orange (Hot at all times) and Yellow/Black wire ( hot when ignition switch is turned on) for presensce of battery voltage. If voltage is not present, check the fuses for battery voltage. If voltage is present at both fuses, there is a break in continuity between the fuses and connectors to the radio. Clock and radio shares common fuses.