All train doors were unable to open in ATPM modes. Open Door button was not working. TC confirmed tr ain was aligned to CSP. TC operated ESDC to open and close P SDs and train doors. TC proceeded in AM to next station. ~~~~~ No FC. From ER and ATS playback, found train arrived at Station in ATPM mode and #3553 was occupied with ZVAR energised. #3554 ATO B/S was energised. DIR dropped and SDIR remained high. TC changed mode to RM and AM mode. Subsequently DIR and SDIR dropped. Which indicates door open. Door closed and departed normally with no anomalies. RS function check satis. Checked 3553 DOSA PB, DORB/DCRB/DOIRB satis. DORB1-1 and DCRB1-1 have high resistance. Replaced preventively as DCRB may caused door unable to open intermittently. To further monitor. Done by Luke. 20/7/2023.