TC reported TIMS showed Front M2 car SMOKE and FIRE Detector Alarm lost power. ~~~~~ 2556 TC reported TIMS showed SMOKE and FIRE Detector Alarm lost power. Reported at BGB SB CE : T409-3556 and 2556 No Sign of Smoke Alarm Activated.  2556 FC 735 (fire and smoke detector lost power). Replaced DC-DC converter. Function check ok. DC-DC converter s/n Old: A103768 New: A103795  Daniel 45483