Servis W/M burning smell

[Jennywrens]

I have used my Servis W/M twice since the first smell to see if the burning smell was a one off.

It's not - after about five minutes into the cycle, a horrible hot electrical burning smell appears.
The machine still runs perfectly through to the end of the cycle.
It is not blocked anywhere as we checked today.
Any ideas what this could be?

 

[Sleepyhead]

Have a look at the pcb to see if it's burning.

 

[Jennywrens]

Have a look at the pcb to see if it's burning.

Where would this be located please? - we have not got a clue where to start?
thanks