I have a NN-CT870W OVEN PURCHASED FROM AMAZON IN MAY 2013 AND WHEN I SWITCHED IT ON PRESSED THE START BUTTON IT WENT ' POP' AND DIED. THE 13 AMP MAINS FUSE DID NOT BLOW BUT IT TRIPPED THE CIRCUIT BREAKER IN THE DISTRIBUTION BOX. MikeOS
When i removed the cover a 10amp fuse on a circuit board had blown. this fuse blows when you use the microwave, grill or oven.
You were right, it was the micro switches operated by the door latch.
If I complete the circuit without the switches (the oven will now work with the door open ) the convection oven and the grill work normally but the micro wave starts up but switches off after 3 seconds. No fuses are blown.