Smeg Microwave Instructions For Use Manual page 28

When the oven is operating I can hear some strange noises! Check if:
The food doesn't heat up or heats very slowly! Check if:
The food is too hot, dried out or burnt! Check if:
I hear some noises after the cooking process is finished!
The oven switches on but the interior light does not go on!
27
Instructions for the User
There are any foreign bodies between the door and the cavity
front.
There is any electrical arcing inside the oven caused by foreign
metallic objects (see section on type of ovenware).
The ovenware is touching the oven walls.
There are any loose items of cutlery or cooking tools inside the
oven.
You have inadvertently used metal ovenware.
You have selected the correct operating times and power level.
The food you have put inside the oven is a larger amount or
colder than you usually put in.
You selected the correct operating time and power level.
This is not a problem. The cooling fan keeps on working for
some time. When the temperature has dropped sufficiently, the
fan will switch itself off.
If all the functions work properly it is probable that the lamp has
blown. You can keep on using the oven.