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Ty Gwyn

Microwave

There seems to be a problem with my microwave,
Its a Sharp 40litre microwave,grill convection oven,and last night it would`nt warm my dinner,
Everything else bar the microwave works,done all the checks in the manual and still no microwave.

Any of you savy electronic friends have an idea what part is needed to fix said microwave as reluctant to replace when everything else works.
sean

Is it behaving as if it's working but not warming the food? Or is it just refusing to even turn on in microwave mode?
Ty Gwyn

Is it behaving as if it's working but not warming the food?


Yes.
sean

Probably the magnetron then. You'd need the model number to order a new one.
Ty Gwyn

Thank you Sean,
Have you ever fitted one or had one fitted,reason i ask is my local electrical shop came out with the same old speel,``How old is it``
So can imagine what the answer will be after they have checked it over.
sean

I haven't, sorry.
Graham Hyde

Hi Ty Gwyn. Be careful when opening the microwave, there will be a large capacator with the capability to deliver a fatal shock even when the oven is 'unplugged'.
Shane

Local electrical shops generally won't touch broken microwaves due to the capacitor issue - they will deliver a fatal electrical shock if not handled properly. Specialists have some clever trick by which they discharge the capacitor, but if you leave the machine unplugged for a few days it will discharge by itself.

I've changed the magnetron twice now in our microwave. Fairly straightforward if you're good at taking things apart and putting them back together again. Every time ours has blown, I've been disappointed at the range of microwaves available in the shops compared to our old one, so a 30 quid magnetron from Ebay is a no-brainer!

Please do take care, though - the capacitors really are very, very dangerous.
Ty Gwyn

Thank you Graham and Shane for the Capacitor warning,

Shane,i take it yours had the same problem as mine,like Sean mentioned,Oven, Grill and timer etc working,but not the Microwave warming food?
Nick

Yeah, handy warning. I had no idea.
Shane

Yep - same issue. Microwave looks like it's doing everything normally (light turns on, turnable goes round, digital screen works) but nothing gets warmed up. Both times it's been possible to see the graphite-looking bit in the middle of the magnetron has cracked. Second time it went I realised the air vent on the back was choked with dust (oops!Embarassed), so I suspect that overheating caused the second failure (first failure was after many years of service, so could well have been age related).

If you take a look at the magnetron you should be able to see the make and model number, hopefully without doing anything more than removing the microwave cover. Pay attention to orientation, as some magnetrons come in two versions depending upon which way the airflows through the unit, although this should be implicit in the model number.

Time for the warning again: The capacitor is very, very dangerous and will kill you if you touch it while it's still charged. If in doubt, take it to someone who knows what they're doing.
dpack

second warning

once you have fitted the new magnetron dont be temped to try it to see if it works before rebuilding the case etc.
an unsheilded one up close can cook your eyeballs etc even better than it will warm a pie.
Ty Gwyn

Being on the safe side,i have left it till this evening before dismantling the cover,
The electrical units including the Capacitor are on the side of this model,the main capacitor[the big one] is in the centre,but there is also another much smaller unit with Capacitor named on it towards the back,
Much to my luck,nothing has Magnatron written on it,

Looked to see the Graphite looking centre,nothing with a black centre that i can see,but one small unit has a Green graphite looking centre,could this be the Magnatron,this is towards the front of the microwave.
Hairyloon

second warning

once you have fitted the new magnetron dont be temped to try it to see if it works before rebuilding the case etc.
an unsheilded one up close can cook your eyeballs etc even better than it will warm a pie.


Is it not fairly directional? Should be reasonably safe as long as you point it away...
Shane

Ty Gwyn - here's a fairly typical magnetron (this one's upside-down):



The cooling fins can be orientated as shown or at 90 to this depending upon how the magnetron is placed relative to the fan, hence my note of caution about making sure you get the right serial number - on the Panasonic ones, it's the last character that designates orientation, if I remember rightly.

Might be worth Googling your model of microwave with the word "magnetron" in the search text to see what images it turns up. Once you've found it and read the serial number, type that in and see what shows up - a pattern replacement should be around the 30 quid mark.
arvo

I have nothing usefut to add that hasn't already been said but this discussion is fascinating. Shane

It has to be said "magnetron" is possibly one of the best words ever for a thingwotsit that actually exists in the real world Hairyloon

So, now that we have a magnetron in our hand, does anybody know how they are getting on with using microwaves for wireless energy transfer... Ty Gwyn

Thank you Shane,that picture has helped enormously,

It sits right above the main Capacitor and is a doddle to replace,

I presume i will be able to see if the Graphite is cracked after removal,as it is,its mainly metal looking at it,but like yours,the air vents at the back were kind of partly blocked,and as the cooling fins face the fan inside the vents,that could be the reason it packed up,but it is around 8yrs old.
Jamanda

It has to be said "magnetron" is possibly one of the best words ever for a thingwotsit that actually exists in the real world

We were just saying the same. It sounds like it should transform into a spaceship or giant robot or something.
dpack

So, now that we have a magnetron in our hand, does anybody know how they are getting on with using microwaves for wireless energy transfer...

it works rather well for toasting a crowd

heart warming

as for running the fridge and telly i dont think so Laughing
Shane

Ruining the telly, maybe Laughing Hairyloon

I'm thinking you may have misunderstood. Look up "power beaming".
I'm thinking it may be a way of getting energy from a hydro plant in the river back to the house without a load of expensive copper.
Shane

Was talking about this yesterday with our corporate innovations man. He was saying that there are new capacitors being developed that can store the same energy density as liquid fuel, and can be recharged at over 100 Amps. Made of sheets of carbon fibre a few atoms thick, just for extra coolness.

I thought it would be pretty cool if you could fit them to cars and have power beaming stations embedded in the road so that you could recharge them on the move.
Hairyloon

Was talking about this yesterday with our corporate innovations man.
Why did my careers adviser not tell me about that job?! Bit -ing late now.

Quote:
Made of sheets of carbon fibre a few atoms thick, just for exta coolness.

Do you mean graphene? I think I heard the same tale on the wireless.
I was most surprised to be told that it was first made using ordinary sellotape. Apparently, all you do is stick it on a block of graphite and pull it off, it takes a layer with it, stick tape to the layer & split the layer. Repeat until you're down to one atom thick.

Quote:
I thought it would be pretty cool if you could fit them to cars and have power beaming stations embedded in the road so that you could recharge them on the move.

I understand they have flown model helecopters with it, but I'm not convinced about charging cars on the move.
dpack

re non wire energy transfer there are rumors of some of teslas's ideas being developed and tested .

perhaps with weaponisation rather than sharing energy as the motive the tech might get to a functional stage but probably not in the best way it could be used .
Hairyloon

re non wire energy transfer there are rumors of some of teslas's ideas being developed and tested .

perhaps with weaponisation rather than sharing energy as the motive the tech might get to a functional stage but probably not in the best way it could be used .
I believe it is functional, but not terribly efficient. It depends what you want it for: the big idea is beaming energy down from orbital solar collectors, we're a way off that I think.
Shane

Was talking about this yesterday with our corporate innovations man.
Why did my careers adviser not tell me about that job?! Bit -ing late now.
The innovations thing is a fun little sideline for my group - and it means we get to do some cool stuff like play with Formula 1 teams.

Quote:
Made of sheets of carbon fibre a few atoms thick, just for exta coolness.

Do you mean graphene? I think I heard the same tale on the wireless.
I was most surprised to be told that it was first made using ordinary sellotape. Apparently, all you do is stick it on a block of graphite and pull it off, it takes a layer with it, stick tape to the layer & split the layer. Repeat until you're down to one atom thick.
<Reaches for the sellotape>

Quote:
I thought it would be pretty cool if you could fit them to cars and have power beaming stations embedded in the road so that you could recharge them on the move.

I understand they have flown model helecopters with it, but I'm not convinced about charging cars on the move.
Hey - innovating is about coming up with fancy ideas. No-one ever said anything thing about them actually being feasible.
Shane

the big idea is beaming energy down from orbital solar collectors, we're a way off that I think.
Doesn't that big yellow thing do that quite well at the moment?
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