TIMS showed Smoke External Alarm at car3510. Staff(YSH) checked and confirmed no signs of smoke on exterior or interior of train. Rear T201 line clear and conf irmed no abnormalities. ~~~~~ TIMS showed Smoke External Alarm at car     Check Tims FC-721 smoke external fault,further check no water imgress into Pcb.Change out as preventive measure.Function test ok. #3510-Smoke detector:- Not: 2480967 raise. Done by Rizman/Koh. 18/04/23