Chef select electric fan-forced oven not heating properly

Kerry requested 2 quotes from Appliance Repairmen in Little River

Oven element works on grill but not the fan-forced oven cycle .
Googled it and it seems like a common fault with these ovens

Oven not working
technika oven electrics not working.

Oven repair
whenever oven turned on, the main safety switch gets triggered

Heater switch fixed or replaced
fan and timer works but heater switch does not. needs fixed or replaced

2 new hinges for modern maid oven and lightbuld for oven replaced
Modern Maid Oven needs 2 new hinges (heavy duty??) and the oven light...