What was found
PROP DE-ICE CAUTION LIGHT. SELECTED OFF & CAUTION LIGHT EXTINGUISED, SELECTED BACK ON AND PROP ADVISORY LIGHTS NEVER RE-ILLUMINATED. DIVERTED AND ACCOMPLISHED AN UNEVENTFUL LANDING. INTERROGATED CDS, NO FAULTS. CW FIM TASK 30-60-00-810-807. CW ELECTRICAL CONTINUITY CHECK OF NR 1 & NR 2 PROP DEICING HEATER ELEMENTS IAW AMM 30-61-00-760-801. NO DEFECTS. CW GVI OF BOTH NR 1 & NR 2 PROP DE-ICE LEADS & BRUSH BLOCKS. NO DEFECTS. CW FUNCTIONAL TEST OF THE PROP DE-ICE SYS IAW AMM 30-61-00-720-801. TEST PASS. IAW MAINT CONTROL. R & R NR 1 TMCU. REPLACED NR1 TMCU IAW AMM TASK 30-61-06-000-801 AND AMM TASK 30-61-06-400-801. CW CALIBRATION PROCEDURE FOR THE TMCU IAW AMM 30-61-06-820-801. NO DEFECTS NOTED. OK FOR CONTINUED SERVICE. REPLACED AS A PRECAUTIONARY MEASURE.