TC reported 'A' side cab door was unableto close after opening. TC holding on to cab door to remain closed. ~~~~~ #3621 A/S cab door found lock cylinder (top latching) tongue stuck. Latching motion being impeded by base mounting holder and tongue was rubbing against base mounting holder. Removed lock cylinder and add 1mm shim to prevent rubbing against the base mounting holder. Carried out door function test ok. Door latching overlapping 4mm within criteria (3mm to 5mm). Done by Joshua/Koh/Sanip. 21/08/20.