Turn off pop

Hi all, My Marantz 1060. Runs perfectly when on,or left on,however when it is turned off popping sound through one speaker? On and off switch or something more sinister?Sometimes the push button switch does get stuck.
Could be the power supply capacitors are getting old and releasing their charge too quickly.
A blown transistor or something like that.
A blown transistor would make one channel quieter and distorted.
probably needs to be recapped. sounds like a discharge issue or abnormal amounts of dc offset.