Imran, you are really saving me today. I have almost that exact schematic but it is dated exactly 1 year older, 25.3.98, and was clearly drawn by someone else in a completely different style. About the only difference is the 'without brake' dashed line to ground.
FelderHQ Austria is not responding to my email so I will remove the board and take it to the repair shop today.
Finally I believe the mystery diode is located on the top of your board.
