What was found
THE LANDING GEAR WOULD NOT FULLY RETRACT AFTER TAKEOFF, OR EXTEND WHEN GEAR DOWN WAS SELECTED. THE EMERGENCY EXTENSION SYS ALSO FAILED, SO THE ACFT WAS FORCED TO LAND WITH THE GEAR UP. TROUBLESHOOTING DETERMINED THAT DIODE CR32 HAD SHORTED, CAUSING THE LANDING GEAR CIRCUIT BREAKER TO OPEN. ONCE THE DIODE WAS REPLACED, THE SYS OPERATED NORMALLY.