Testing a magnetron
Discussion
In a microwave oven which doesn't work one obvious potential failure is the magnetron itself - the bit which emits the microwaves. Is there any DIY way to test the thing without risk to life and limb, given as how microwaves are just a tad dangerous? For instance, on an ohmeter would a good magnetron show continuity across its terminals and a failed one show no circuit?
ThatPhilBrettGuy said:
Easiest way it to check if voltage gets to it (if you can the right meter). If it has power and the food doesn't get hot it's dead. What symptoms does the microwave have?
DONT DO THIS!there is never any need to measure the HV to a microwave magnatron and it is potentialy lethal to do so. Microwaves are not user servicable.
Edited by eastlmark on Monday 4th January 12:50
eastlmark said:
ThatPhilBrettGuy said:
Easiest way it to check if voltage gets to it (if you can the right meter). If it has power and the food doesn't get hot it's dead. What symptoms does the microwave have?
DONT DO THIS!there is never any need to measure the HV to a microwave and it is potentialy lethal to do so. Microwaves are not user servicable.
ThatPhilBrettGuy said:
eastlmark said:
ThatPhilBrettGuy said:
Easiest way it to check if voltage gets to it (if you can the right meter). If it has power and the food doesn't get hot it's dead. What symptoms does the microwave have?
DONT DO THIS!there is never any need to measure the HV to a microwave and it is potentialy lethal to do so. Microwaves are not user servicable.
eastlmark said:
not the case, the fact you even suggested such a thing speaks volumes about your knowledge of microwaves. Dont go there mate, YOU will get in big trouble if something were to happen to the OP.
I used to design and work on radar and troposcatter transmission systems. You can read about it if you like, some of it was in this book http://books.google.co.uk/books?id=fBJKfP1meKQC&am...What do you do?
As to the OP, if you're not careful you'll die. There you go, consider yourself warned
P.S
Don't run with scissors either.
Ozzie Osmond said:
Never fear, I'm aware microvave is a staggeringly dangerous piece of kit, hence my question about whether there's any simple way to check the magnetron - assuming everything is completely disconnected from the mains.
Generally with home kit, not. What does it actually do? It's usually the interlocks that go stopping them firing up. You should check the door switches etc before anything else.dickymint said:
Doesn't always work though sadly. They can pass those checks and still not transmit on occasion. Some are a right pain and will go open circuit when the power's applied 
ThatPhilBrettGuy said:
What do you do?
and me just an appliance engineer doing these things all day long, what do I know and I certainly wouldnt be giving any advice on someones radar system just 'cos the 2 products work on the same principle.and thankfully the OP seems a sensible person well aware of the dangers of these appliances (HV shock and capacitor discharge shock as well as the normal dangers associated with mains appliances) which is just as well.
Edited by eastlmark on Monday 4th January 13:39
eastlmark said:
thankfully the OP seems a sensible person well aware of the dangers of these appliances (HV shock and capacitor discharge shock as well as the normal dangers associated with mains appliances) which is just as well.
Thanks for that vote of confidence! Yes, of all the appliances which say "don't mess about inside" your microwave is the one which really means it. As well as the danger from microwave radiation there are some very high voltages and currents kicking around.Mine's now at the local repairer who has diagnosed a failed magnetron (surprise, surprise) and a bill for £90 is headed my way. Yes, I know that's more than a basic new microwave would cost but unfortunately it's a built-in appliance and repair is much cheaper than replacement.
PS I just love the way you open up any domestic box of tricks and it's almost certain to say "Panasonic" on the bits inside.....
Ozzie Osmond said:
eastlmark said:
thankfully the OP seems a sensible person well aware of the dangers of these appliances (HV shock and capacitor discharge shock as well as the normal dangers associated with mains appliances) which is just as well.
Thanks for that vote of confidence! Yes, of all the appliances which say "don't mess about inside" your microwave is the one which really means it. As well as the danger from microwave radiation there are some very high voltages and currents kicking around.Mine's now at the local repairer who has diagnosed a failed magnetron (surprise, surprise) and a bill for £90 is headed my way. Yes, I know that's more than a basic new microwave would cost but unfortunately it's a built-in appliance and repair is much cheaper than replacement.
PS I just love the way you open up any domestic box of tricks and it's almost certain to say "Panasonic" on the bits inside.....
You are not alone with the built in dilema, a lot of folks have to fork out £100's for a repair on something they could buy new at Tesco for £30 just because its built in and nothing else will fill the gap.
I mended one that had a thermal fuse link that tripped when the cavity overheated due to running with no-load in it. Easy fix. But I agree with the people who say do not mess with magnetrons. I've worked extensively with little 1 watt Gunn diodes in waveguides and even they have to be treated with respect.
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