Sharp Combi oven thermal fuse

[Stevie-b]

My much loved Sharp R-7E53 Quartz Chef microwave / grill / convection oven has been working flawlessly for 25 years!!!! About 6 weeks ago it died. I traced the problem to a thermal fuse at the back where I think the convection oven element is located.
I bought a used replacement fuse, fitted it and everything worked for several weeks but now the replacement fuse has also gone open circuit.

The fuse is a Klixon (by Sensata) 1NT01L-1757, L160-180 (no longer made)
From the spec sheet I gather this is an auto reset fuse that should open at 180 degree C and close at 160 degree C.

Am I right in saying that this is supposed to operate only in unusual, possibly dangerous situations i.e. temp outside the oven cavity is higher than it should be?

What should I be looking for as the cause?
Faulty oven thermostat? Faulty fan? Something else?

[electrofix]

any safety cut out is meant to stop excess tempertures from getting out of hand

was the oven temp high ?

Dave

[Stevie-b]

Thanks Dave.
First time it happened my pie was a darker brown than normal :(, second time didn’t notice anything unusual.
So the fuses should have reset themselves but didn’t – too old to function properly?

I might invest in an oven thermostat to check the actual oven temp. What switches the oven element on/off to achieve the requested oven temp?

[electrofix]

there will be a temp sensor. Even at that age it will probably be an electronic thermistor which feeds back to the board to control temp

Dave

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