Train doors not proven at Rear DT car 'B1'. TC opened and closed a few times to no avail. Staff(MSP)checked and confirmed train door no abnormalities. Staff(RF P) checked and confirmed no abnormalities. ~~~~~ Train doors not proven at Rear DT car 'B Check and found B1 door LHS & LHS inner roller chip off.Change out done.Door actuator checked ok.Door cycle ok.10mm gauge test Dir lit ,adjusted and test ok.20mm test ok.Door statle test ok.ER unable to down due to software corrupted. Done by Sanip/Koh. 06/07/24