TC reported TIMS showed "Aux power supply inverter input" failure at Front M1 car. TC reported trainjerks intermittently. ~~~~~ TC reported TIMS showed "Aux power suppl   1670 No FC. All other cars no FC at time of fault. From ER observed 1670 line voltage dropped multiple times with friction braking. No propulsion fault, no propulsion inverter fault and no WSS. Checked APS panel no signs of abnormalities, fuse F1, F2, AF, MF ok. Battery charge panel no signs of abnormalities. Aircon motor and condensor fan ok. Propulsion pre charging resistor ok. APS no power / power test ok. CCD height ok, CCD fuse A1 blown and replaced. To be further monitored in mainline. Done by: Zulq / Saini 45144