The way I found I had a bad cap, was by a green goo I found on the rack. Glad you will have a cleaner time of it.
Is my capacitor bad?
My capacitor has a bit of oxidation indicating some leakage, but no liquid come ng down the sides or on the board. See photo. Will changing this improve the sound?
Also, if the specs are the same, does it matter which brand I use? I'm replacing Elna which I'm assuming (guessing) w