Another new project

We just acquired my friend's Spanish Style Sears Silvertone Stereo Radio Phonograph Console.   It's huge....It's beautiful!   However , the receiver has a huge amount of AC Hum and the turntable is in bad shape.  This is going to be a major undertaking. 

As you can see we tested out some of the connections with the white bose speaker to see what works and what doesn't. 

So we pulled off the back and we figure the source of the humming noise is coming from the amplifier power supply.  The red and silver cylinders are capacitors and we are hoping one of the big ones is the problem.   From doing research we have found that these capacitors are probably electrolytic capacitors.  Only thing I know so far about electrolytic capacitors is that they hold a lot of electricity even when the stereo is off (which means be careful) and unplugged and they don't look any different when they go bad.