I have a Pioneer VSX-32 Reciever which works fine for the first ten minutes or so then starts making a boom boom noise continuously.It seems to be that this happens once the receiver has “warmed up” so I suspect the power supply to be the issue but don’t have a wiring diagram/knowledge of how to test this.Has anyone had any similar problems that could help?

 

Service manual available here: https://elektrotanya.com/pioneer_vsx-32_33.pdf/download.html . But it doesn't look complete to me. Hopefully it will be of some help.