Smeg A2-5 no power at the oven fan element ?

I can only give a suggestion after reading your description, as I have no experiance working on your oven. When you mention that the cooling fan is on all of the time, even when not switched on, I would suggest investigating the relevant temperature probe. It sounds like the control computer thinks the oven is hot (when it is not) because it is being fed incorrect data from a faulty probe. This would also result in the heater element not being supplied with power by the control system.

Rupert
May 2020