What was found
COMPLETE ELECTRICAL FAILURE. WHEN BATTERY MASTER SWITCH WAS TURNED ON, NO POWER REACHED MAIN BUSS. FOUND BATTERY AMMETER SHUNT BURNED THROUGH. BATTERY AMMETER SHUNT INSTALLED WAS 30 AMP VALUE. (P/N MS91586-1) BATTERY AMMETER SHUNT SHOULD BE 100 AMP VALUE. NO RECORD OF BATTERY AMMETER SHUNT BEING REPLACED SINCE AIRCRAFT WAS MANUFACTURED. INSTALLED CORRECT AMP VALUE SHUNT AND ELECTRICAL SYSTEM OPS CHECKED GOOD. PIPER P/N 486-684 (MS91586-6) RECOMMEND THAT ALL SHUNTS BE CHECKED FOR ALL THIS MODEL AIRCRAFT. (ALTERNATOR AMMETER SHUNT IS SAME P/N)