Thanks,
I will buy some to have a spare board on hand.

Failed diodes D4 & D5 (FR15 with RG underneath)
Failed Transistors / FETs Q1 & Q2 (brand name is a lower case f, the numeral 6 in the centre, K41 with J1 3007-2 underneath)
Guess I should try to find components with a higher heat rating)


Happy is he who penetrates the mystery of things.