Integrated stopped working

I run a retro repair workshop, most retro faults are dry joints on the solder.
90% are repaired the same day after a complete resolder and pot/switch service with wd40.

I run a retro repair workshop, most retro faults are dry joints on the solder.

Bingo. What I said.

Guys, thanks for all the responses.  As many have suggested, I’m gonna pull the fuse and test it.

regarding the power cord, I unplugged and replugged many times with no luck.  I have two other devices on this same receptacle, so I know I have power at the wall.  It would be strange to me that almost a year into the integrated and without it be moved at all, the power cord would fail. 
My daughter unplugged the power strip all my devices are plugged into yesterday to reset the TV (which we do on a regular basis) and everything came back on except the amp - gotta be the fuse, right?  
I’ll pull it today to confirm.  Again, thanks for all the help.

wd40 into a switch? I hope that's the dielectric electronics cleaner your using and not the old school WD40 ah lubricant (cleaner really), that's not a dielectric and not good for electronics.

I checked the fuse with a multimeter tonight and it’s good.  So... I don’t really want to crack open the case, but it might be my only other option.