Smell of Burning Plastic When Used. No Sign of Burning Outside

Is it a plastic burning smell? It sounds like the magnetron is overheating. Can you hear the cooling fan running? Is there anything blocking the vents on the unit?

Burning plastic, not food? A component has overheated badly then, with a plastic case. The main suspect would be the high voltage capacitor in the magnetron supply. This is cheap and easily replaced ONLY IF you know what you are doing and can diagnose the fault. If you don't then DO NOT take the case off the unit as fatal voltages can be present inside even if the unit is unplugged.

I'd just buy another, as they are generally uneconomical to have repaired by a service tech.

you must open inside see the diagram, and see 1) burn cable 2) fuse 3) diode 4) capacitor 5) magnetron 6) bulb etc.
God bless you

Is the smell ionized (the outside smell of a cold winter morning air) or more of an electronic component burning??? if it's more of an ionized smell it could be normal, (if the smell is strong) it could be a leaking high voltage cable (electric arching) bad insulator, if it's more of an electronic component burning smell, it could be a overheating component, in both cases you should have it checked by a professional technician...

Cheers!

This is almost certainly some of the protective oils and varnishes which were applied during manufacture flashing off.

All new products of this type do this to some degree but your description seems to indicate that it's much worse than normal with your machine.

Ordinarily, you can expect this to cease after a few uses and if the level of smoke and odour you've described is to be expected then the instruction booklet should say so. But as yours has visible smoke and a burning plastic smell I'd recommend that you exercise your rights under the Sale of Goods Act and return it to Tesco for a full refund or replacement. The smell of burnt lubricant is one thing, but a burning plastic smell means you can never trust the oven to be safe: none of the many microwave ovens which I've dealt with have ever smelled of burning plastic unless there was a fault.

You won't find any objection from Tesco as they do have good customer service; and when I lived in Cullompton briefly earlier this year the local branch was even better than usual at keeping customers happy.

I hope that you have found my reply to be of assistance and ask in return only that you return the favour by rating my answer.

If it buzzes real loud it's probably the high volyage diode. However some times if it smells it's the transformer. Usually the diode is a cheap fix ~$10.00 but this model the diode is $50. It's number 50 on the link below. Let me know how it works out or you need anything else.

http://www.searspartsdirect.com/partsdirect/getSubComp.pd?modelNumber=JVM1440BH01&productCategoryId=0123370&brandId=0432&modelName=MICROWAVE&diagramPageId=00001&documentId=G0312014&pop=flush

Hi,
Here is a tip that will help you to figure out what is wrong with your Microwave Oven....

Microwave Oven Basic Troubleshooting Tips
http://www.fixya.com/support/r5508031-microwave_oven_basic_troubleshooting

heatman101

the control circuit shorted out from the cleaning session and kept the microwave on so long with nothing to cook that it has cooked itself I'm sorry to tell you. Probably not worth repairing

If you clean any appliances always plug out the unit power supply do spray any liquid in the unit that can enter inside the control, instead just wipe it with rug not spray. In this situation you have to call for a qualified technician. Maybe there are some wires that burned or rust in the control that cause the short circuit inside the unit..

replace plastic inner and check any rust is there, check inside body and compleat door.