What was found
GEAR RETRACTED NORMALLY ALL LIGHTS WENT OUT 3-4 SEC LATER. LT MAIN GEAR UNSAFE LIGHT (RED) AND WHITE TRANSITION LIGHTS ILLUMINATED FOR 4-5 SEC. DOOR CAUTION LIGHTS DID NOT COME ON. ALTERNATE GEAR EXTENSION WAS PERFORMED. RETURNED TO THE FIELD LANDING UNEVENTFUL. FERRIED FOR REPAIRS. REPLACED PSEU AS PRECAUTIONARY MEASURE, REPLACED LOOSE RIVETS ON LT MLG AFT DOOR PROX SENSOR BRACKET, REPLACED ALT RELEASE CAM (BINDING), ADJUSTED LT, RT MLG AFT DOOR PROX SENSORS, OPS CHECKED GEAR- OPS CHECKED GOOD. RETURNED TO SERVICE.