On Tue, 10 May 2022, Peter Coghlan wrote: > Ahead of the 78M09 is another TO220 package marked D45H8 which seems to > be a transistor. Then I am completely lost. I can't find the rectifier That TO220 part would be the rectifier. It either has two legs (simple diode) or three (two-wave rectifier with presumably common cathode). Christian