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Microwave oven arcing...

Externet

Active Member
Hi all.
My two week new microwave oven wants to visit a dumpster... But I really wanted this one. The two wires that go from the transformer to the magnetron are arcing to the transformer core (ground) with the corresponding scary noise.
Opened, separated the wires from the transformer and it is working. Wires have their insulation with signs of suffering but holding.

This picture is borrowed from the web for a similar oven. The wires are like the white pair passing above the transformer, arcing towards the white label on it.

1585781063763.png

What should be done/checked ? Will try to claim warranty, but would like to know/learn what is going on, if keeping the wires away could ensure a long life... Any suggestions ?
 

sagor1

Active Member
2 weeks old? You can probably return it to place of purchase for a refund, let alone a warranty...
 

Externet

Active Member
Thanks. Yes, Warranty should work, I already requested, but... Would anyone know what is going on with this kind of failure ? Am prepared even to canibalize other ovens if I have to replace any guts it may need in the event that cannot find/claim another. (It is stainless inside, and that is the only reason I bought it)
 

sagor1

Active Member
It could very well be that the oven was defective in the first place, not that there was any "failure" per se, but some bad manufacturing or original components.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Thanks. Yes, Warranty should work, I already requested, but... Would anyone know what is going on with this kind of failure ? Am prepared even to canibalize other ovens if I have to replace any guts it may need in the event that cannot find/claim another. (It is stainless inside, and that is the only reason I bought it)
In my previous career I repaired hundreds, probably thousands, of microwave ovens, both in and out of warranty - and I've NEVER seen any such failure.

As we don't have an actual picture of the fault, I can only surmise that the wiring was badly placed by the assembler, and was touching the transformer body, rubbed through the insulation, and started arcing.

Simply moving the wires away from the transformer 'should' stop it arcing?.
 

Externet

Active Member
Hi Nigel. Moving the wires away from the transformer core cures the problem, no more arcing. Used it yesterday and this morning. Works normal.
My curiosity finds some backup if you have never seen such failure mode with all your experience. Neither did I.

Would like to muffle somewhat the normal hum noise when operating, if there is a way.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Hi Nigel. Moving the wires away from the transformer core cures the problem, no more arcing. Used it yesterday and this morning. Works normal.
My curiosity finds some backup if you have never seen such failure mode with all your experience. Neither did I.
I can only imagine it was poorly assembled, with the wires rubbing on the transformer - as you know, the wires are quite solid, and are normally formed in place well away from the transformer.

Would like to muffle somewhat the normal hum noise when operating, if there is a way.
Buy a MUCH more expensive Panasonic Inverter Microwave Oven instead :D

The hum is simply the mains transformer under load.
 

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