What was found
AFTER TAKEOFF, COULD NOT RETRACT LANDING GEAR NORMALLY. RETRACTED GEAR WITH THE OVERRIDE SWITCH BUT GEAR UNSAFE LIGHT ILLUMINATED. RETURNED TO BOS AND GEAR EXTENDED NORMALLY. REMOVED AND REPLACED K5, K6 AND K8 GROUND RELAYS AND K9, K10, K11 AIR RELAYS AND LANDING GEAR ACCESSORY UNIT. PERFORMED LANDING GEAR RETRACTION CHECK IN ACCORDANCE WITH MAINTENANCE MANUAL CHAPTER 32-11-00 AND OPERATIONALLY CHECKS NORMAL.