Many years ago (far too many to disclose) I used to go out to repair rental TVs. These were valve sets and the practice to brighten up an ageing CRT was to take the eht cap off (using insulated tools) and whizz the end round the tube end connector whilst the set was switched on. The eht sparking effectively removed any crude on the cathode. This rejuvenated the TV. However, I would never suggest this practice with any system with semi-conductors.
Has Anyone else used this technique?
