Combi Microwave Panasonic Problem

[barry1010]

Don't know if anyone has any ideas on this. It's a few years old but has never been any trouble.
Still works fine on microwave mode but on fan oven it bangs very loudly every few seconds.
The sound seems to be coming out of the back.

The model number is NN-CF778S

[Hopkirk]

Something is probably hitting the fan blades.

[barry1010]

I can't imagine what, the fan is fully encased with just a few slots at the back of the oven.
Looks like I've got to get somebody in to fix it.

[fender62]

id take it apart unplugged of course, could be somehting simple like a loose screw, if the fan is shot, you could probably get a replacement and fit it yourself. probably has a 3 or 4 pin connector.

[barry1010]

I'll have a go. Pray for me

[Tilly2]

You can do it, Barry!

[barry1010]

Not tonight, Josephine

[anneasquith]

Saucy !!!

[Old_Geezer]

Beware the very high voltages that I understand are created inside the microwave.

[barry1010]

Additional info. Still working as it should on microwave but I don't think it can be the fan causing the banging.

I turned on convection today and it was fine for 7 minutes then the banging started, every 30 to 40 seconds. It carried on even when I'd stopped the programme.

Any idea before I take the back off tomorrow?

[fender62]

take the back off before you turn it on, then put something in the microwave bow of water or something, then look at the back, narrow down where noise is coming from.