Quote Originally Posted by Rudeofus View Post
2. Discharge all electrolytic capacitors and make double sure they are indeed discharged.
Don't do it by short-circuiting (e.g. a screwdriver or a piece of wire)! Rather for use a resistance that is able to absorb and emit the energy. A 50-150W light bulb (rated for 220-240V) is quite good for this, it will take some time (up to a minute) until full discharge.