As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A LOUD BANG SOUND WHEN ENERGIZING EITHER HYDRAULIC SYSTEMS NR 1 OR 2. INSPECTED AND FOUND THE LANDING GEAR FREE FALL CONTROL CABLE WRAPPED AROUND THE NLG UPLOCK BOX. REMOVED AND REPLACED THE RT NLG DOWNLOCK AND RT MLG FORWARD DOWNLOCK PROXIMITY SWITCHES IAW AMM 32-61-02. OPS CHECKED GOOD IAW 32-63-05. GEAR SWINGS GOOD IAW AMM 32-34-00. COMPLIED WITH GVI OF LANDING GEAR FREE FALL CABLE AND FREEFALL SELECTOR VALVE. NO DEFECTS NOTED.