What was found
(PIREP) NOSE GEAR WOULD NOT EXTEND USING NORMAL HYDRAULIC SYSTEM. GEAR EXTENSION USING ALTERNATE SYSTEM. (MX) REMOVED AND REPLACED RELAYS 3261-K11 AND 6231-K7 IAW DHC-8 WD 32-30-00 PG 1 SHEET 4. DID NOT SOLVE PROBLEM. (MX) REMOVED AND REPLACED NOSE GEAR DOOR MECHANICAL SEQUENCE VALVE IAW DHC-8 MM 32-20-31 PAR 1 PG 201-202. OPS CHECK AND LEAK CHECK GOOD. PERFORM EXTENSION AND RETRACTION OPERATIONAL TEST OF LANDGING GEAR IAW DHC-8 MM 32-30-00 PAR 2 PG 203-206. NO DEFECTS NOTED. NOTE; POST MAINTENANCE CHECK FLIGHT (PMCF) GOOD.