The past few days, our lights have occasionally flickered, something that doesn't usually happen here. I suspected it was our local substation which had gone wrong once before, but we've now noticed that the microwave randomly starts cooking by itself! It's clearly faulty, but do you think the two issues are related? I imagine the high current fuse in there won't blow immediately so brief shorts in it could cause power drops?

It is unplugged now for safety and is going to need repairing (quite new, but out of warranty typically!). I'm not even sure how you go about repairs, I don't think there are any generic repair shops in this whole town! Posting a microwave can't be too cheap either.

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Angry!? I'm absolutely electrolytic!

Will have to make do with myspace now I guess...

 

How much did your microwave cost?
It probably isn't worth repairing.

Before you go and through it out, have you had any problems with other appliances behaving like this?

You could try connecting to microwave to a different socket or leaving it plugged in a different room. with a cup of water inside just in case it randomly starts.

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What make of microwave is it?. Do your lights flicker when you normally cook with it?, they shouldn't do!.

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It is a Sanyo super showerwave. The lights don't normally flicker when we use it, it's just that as it seems faulty I thought it might have developed an intermittent short inside. That said, the lights do dim briefly when the hoover starts.

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Angry!? I'm absolutely electrolytic!

Will have to make do with myspace now I guess...

 

It might be the mains fluctuation is crashing the micro-controler in the microwave, and causing it to start cooking? - rather than the microwave making the lights flicker.

__________________
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two things to consider:

1. get a spike/surge protector on your outlet for when you get it repaired or replaced with a new one to reduce the chances of reoccurrence

2. contact your local power co. and have them issue you an "event monitor report". It will list in detail any electrical event (short of normal activity) along with dates and times. That said, your homeowner's insurance may cover repair or replacement of any and all affected electronics in your home, if they determine that failure was due to faulty electricity supply. It all depends upon your insurance policy details.

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Don't make me reach through this monitor to slap you a good one!

 

well that's one problem that must be fixed by an electrician. If your lights are dimming a little when it runs normally that means the microwave outlet is running on a light circuit. (or so it sounds like it is)

A microwave must be on its own dedicated 20A circuit. Our house has the microwave on the counter outlet currently but this winter we will be wiring an outlet for it from the new sub panel.

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Dave

www.myspace.com/sonicorbstudios

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You're not paying attention to the location in the profile, the OP is in the UK, you don't have sockets on lighting circuits, nor do we have 20A fuses.

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good point...ok than im clueless as to the cause of the problem...it will be interesting to find out what it is in the end though.

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Dave

www.myspace.com/sonicorbstudios

Welcome to "Sonic Orb Studios"

 

I'm currently thinking the lights probably were unrelated and that Nigel was right saying that the power drops caused the microprocessor to go wrong. There is a self start mode on there (goodness knows why tbh) where it starts after like 30mins on a timer. Mabye it set itself into that mode. It's been plugged in for the past few days without problems anyhow.

__________________
Angry!? I'm absolutely electrolytic!

Will have to make do with myspace now I guess...

 

Just because the lights dim it doesn't mean it's wired to the lighting circuit. The lights dim slighly in our house when the vacuum cleaner is turned on but our sockets certainly aren't on the same circuits as the lights. There is a sudden volt drop on all the circuits when the huge surge takes place; this are caused by the resistance between the house and the mains.


As nigel said microwaves are on the same circuit as everything else in the UK. This is because we have 230V 13A sockets so the loads can be as high as 3kW. You only have 120V 15A which is only 1.8kW. Bigger loads are on separate circuits, and even larger loads like heaters, cookers and air conditioning are powered from 240V. The whole house is powered from a 120V-0-120V split phase system whic makes this possible.

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Screen name: Aloone_Jonez

 

Loads of the sanyo Microwaves I worked on had a steam problem with the touch membrane on the front panel...after a week or two of semi regular use, the thing would play up, the customer would unplug it and bring it in....by the time it got here it was dry and worked perfectly. Of course we sent them back out the first few times, putting it down to anomalies in their mains supplies etc. However, after a couple of them reported that the same problem returned, a service call was arranged instead, and one of our engineers caught it in the act on-site.
So if it starts playing up again, disconnect it, leave it 10 mins, then remove the cover and unplug the ribbon cable for the front panel, rebuild it and power it up again and leave it sitting on standby for a few days and see what happens...