/diy/ - Do It Yourself

Hey guys. I have a 60's Heathkit EA-2 amplifier my grandfather put together that I've been using for a while. I have it hooked to a giant GE monitoring speaker from the '40s that came out of my grandfather's radio station.

Recently, the amplifier has created a popping sound when I turn on light switches and it intermittently has a heavy crackley static sound after it gets good and warm.

I don't know a lot about electronics, but from what I've read its either a capacitor going bad, corroded posts on a tube, or RF interference.

I took the cover off and saw that one of the power transformers (I think thats what it is) appears to be leaking. Could this be my culprit, or is this just some sort of melted resin coating?

Should I take the bottom off and visually inspect for bloated caps or just replace them all on principle?