What was found
PASSING 25K' NOSE GEAR RED UNSAFE CYCLED ON & OFF SEVERAL TIMES THEN HELD STEADY. SLOWED & DESCENDED TO CYCLE GEAR. NOSE UP & LOCKED, BUT MAINS WOULD NOT. SLOWED TO 210 & CYCLED AGAIN & MAINS LOCKED. FAILED OPERATIONS CHECK & ORIGINAL UNIT REINSTALLED DURING TROUBLESHOOTING A SERVICEABLE PSEU WAS INSTALLED FOR COMPARATIVE PURPOSES & WAS FOUND TO BE UNSERVICEABLE IAW AMM 31-71-01-2 CONFIG CODE SHOULD BE 34 - 34 FOR MD10-10 & 33-33 FOR -30. NEW PSEU INDICATED 34 - 34 BUT FAULTED PSEU & CTR GEAR INDICATOR. ORIGINAL UNIT WAS INSTALLED & RTS TEST PASSES. VISUALLY INSPECTED MAIN GEAR, NO PROBLEMS NOTED. REPLACED D1-78 SYS B DOWN SENSOR IAW AMM 32-1-17-4 & CHECKED IAW AMM 32-61-17-5. ALL FUNCTIONS & INDICATIONS NORMAL.