No power suggests bad power transformer, bad power switch, blown fuse, blown diodes, or all of the above.
Capacitors don't usually leak their fluids unless there is a catastrophic break down event or an over powering event such as a voltage surge which might lead to their heating up. Almost all capacitors I have seen in vintage SS equipment have been made from the factory with slit tops so that when they do vent, they do so from the top and you will see them split open.
People who see what looks like a wet look on their circuit boards, automatically assume that the cap has leaked over their boards and have not tested them with either a capacitor checker or basic DVM. 99 times outta 100, it is just glue! Plus it is highly unlikely that 2 or 3 or more just happened to spew at the same time.
So for the moment, forget about the capacitors and concentrate on the main power problem and look at the suspects mentioned first. Once you get it working again, it may not need any capacitors replaced but people do so just because it is 30 years old or older.
I am still using some 50 year old amps with their original cans. They are still holding up but who's to say what tomorrow will hold.