So you know what to check, repair kit contains:
Q809 (L78L05)
C877 (15nF/1600V)
C878 (15nF/1600V)
C801 (33uF/63V)
C892 (100uF/50V)
C817 (220uF/25V)
Other known causes of stuck in standby: check D866 for short and F803 for open. Replace IC802 (FAN7529).