Looking for a wiring diagram and a schematic for my naughty oven please.

Thread Starter


Joined Oct 7, 2016
Hi. Smeg freestanding oven. The electrical side of it has shut itself down with a complete loss of functions except for the clock that still runs. I believe there is something wrong with the timer?

Anyways if someone could please kindly help me out with the technical docs I need, the model is a Smeg SNZ90MFX

Rgds Boydage


Joined Feb 22, 2014
Hi boydage, I see there are a couple of electric elements in the oven. These are often the things that burn out, and short the mains to ground (though usually you only see a fault when you switch power on to the element.)

.... actually.. silly question and all.. but the oven (element) hasnt just knocked out the mains supply to it.. tripped the circuit breaker or fuse? (with the clock working on a battery) As this is a common fault when the elements go.
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Thread Starter


Joined Oct 7, 2016

Thanks for that. The fault was intermittent, ie it came right for one operation and then after a couple if times went out. And it is acting exactly like there is a control relay (or whatever it is) that is holding the operation.

No control lights come on when I try to heat the oven. If I can lay my hands on a diagram I will be better armed for troubleshooting.


Joined Nov 6, 2012
Test the input power to the oven FIRST.
You may simply have a bad connection between the Electrical Circuit Breaker and the Oven.
Most Ovens are 240volts (in the U.S.), but the clock and controls sometimes
operate on 120volts.
Your Oven, if it's not more than 20 years old, probably has 4-wires powering it,
( or it SHOULD HAVE 4 wires in any case ),
( sometimes, "fly by night" "handymen" will cheap-out and use 3 wires, BAD )
2 "out of phase" "Hot Legs", (usually Black and Red, although both may be black),
1 "Neutral Wire" (which is a "current carrying" Ground), (usually white or grey),
and an "Equipment Ground" (for safety), which will always be Green, or bare wire.
If one of the "Hot Legs" has a bad connection,
the Controls on the oven "may" appear to work, but you will not get any heat.
This is a common problem in "manufactured homes" because they quite often
have sub-par wiring, and/or, in certain situations, you may be dealing with
Aluminum Wiring, which can be very problematic, and even dangerous.

If you find Questionable wiring feeding your Oven,
do not attempt replacing it yourself.
Call a reputable Electrical Service Company,
yes, they will charge you an arm and a leg,
but it's better than burning your house down.

And last, you may find that you have a defective Circuit Breaker,
or a burned-out buss bar in your Electrical Panel.
You can probably replace a bad Circuit Breaker yourself,
But if you need a new panel, call an expert.

Thread Starter


Joined Oct 7, 2016
Hi. Thanks for that. I am a sparky with electronics experience. I just need a diagram for a start. And if it is the board, I will have a go at repairing the board before I replace it. I just dont want to dismantle it without a diagram which makes life so much easier. Rgds