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Electronics => Repair => Topic started by: attr_writer on November 15, 2018, 07:59:22 am

Title: Convection oven trips/blows breaker at certain temperature
Post by: attr_writer on November 15, 2018, 07:59:22 am
Recently our Sharp R-960N convection/microwave combo oven has started tripping the circuit breaker. This only happens in convection mode when the temperature approaches 140°C. I have tried using it on a different circuit with the same result.

Any ideas what might be wrong? I thought possibly the thermostat but I am unsure. Thanks.
Title: Re: Convection oven trips/blows breaker at certain temperature
Post by: t1d on November 16, 2018, 06:35:22 pm
Just to be clear, you mean the house mains ac breaker, correct? Or, the GFIC breaker, on the kitchen counter wall socket? Our, the device has its own breaker?

If the first, I would think that your house is old enough to not have GFIC breakers and the device does not have a reset. If so, I would do a visual inspection, of the device.

Do not touch anything, inside the compartment, unless you know what you are doing. If you do know what you are doing, here is a reminder, to discharge any caps...

Unplug the device, open the control compartment and look for a wire, or component, near the heat source, that is moving, due to the heat, and grounding out. Look for scorching. Pay attention, for a burnt smell.

Do a visual inspection of the heating element and fan, if you can see it.

Take lots of photos, of everything... Especially, of any observable problem area.

Get back to us, with details... Make and model... Which breaker... Photos, etc.

Do not use the device, until it is repaired.
Title: Re: Convection oven trips/blows breaker at certain temperature
Post by: t1d on November 16, 2018, 07:39:37 pm
The on-line repair parts suppliers usually have the exploded diagrams, of the device. It can help you see how to get into the device. I am not finding that, for you make/model.

There doesn't seem to be anything specific, to your make/model, on YouTube, either.

It may be that this model is not sold in the USA? You may have to research things, on your internet.
Title: Re: Convection oven trips/blows breaker at certain temperature
Post by: capt bullshot on November 16, 2018, 09:57:27 pm
You'll probably have to replace the heating element
Title: Re: Convection oven trips/blows breaker at certain temperature
Post by: johnkenyon on November 17, 2018, 12:56:36 pm
Quote from: capt bullshot on November 16, 2018, 09:57:27 pm
You'll probably have to replace the heating element


Before forking out for a new element, test the theory by temporarily splicing a marginally rated fuse into the feed to the heating element.
By "marginally rated" I mean a fuse which will only just pass the normal current for the element.

For example, if the element is rated at 900W, and the nominal mains voltage in SA is 230v (nominal current 3.91A) , then use a quick blow 4A fuse.
If the fuse blows when the oven gets up to temperature then you can be a bit more certain that it's worth buying a new element.