Microwave emergency! Repair or replace?

Ours made scary noises and what might might be “arcing”, and left a hot, black spot inside. What is that place on the inside of a microwave? It’s not like the others, and Google lens is not helping me.

A microwavable container was being heated; no obvious metal.

Any thoughts?

This one has oven , broil, and convection features, in addition to microwave. It’s probably at least 10 years old, but did what we needed it to do, and probably could have done more.

Never noticed any of these details before today.

My household feels this is an emergency! What does one need to know about shopping for microwaves these days?

We have plenty of “stuff” already.

Probably cheaper to replace a 10 years old microwave than to fix it.


Replace, and get something mid-range rather than fancy. I don’t know anyone who uses the fancy features on a microwave, and the cheap ones seem to outlast the fancy ones.

I would caution to check the buttons on the new one - I find the pre-programmed +30s, 1m very useful and would miss them if a new one didn’t have them.


In my household it is… I keep a spare microwave boxed up in the garage for just such emergencies.
I know I use mine everyday.
I’ve never tried to repair a microwave, just toss it and purchase a new one.

If your previous one has been doing the job, then I’d attempt to find a new one of similar wattage and similar size.

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Looks like it blew a fuse.

Get a new one.

Like most electronics these days, they are disposable items



Another shout=-out for this Panasonic commercial microwave. Incredibly powerful, simple, idiot proof. Just yesterday we commented on what a good little machine it is. Dial only, no buttons. Interior very easy to clean, albeit has not needed more than a cursory wipe down. LOVE IT!

Thanks everyone! So nice to wake up to some answers.

I like the simple theme very much. But this unit, at 1,000W, is at the low end of the power spectrum.

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What are your power needs beyond this?

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My own needs aren’t too relevant, because I use the MWO so seldom and for so little. But more power translates to faster cooking/defrosting, and I think deeper penetration into foods.

I was mostly responding to your comment about the Panasonic being “incredibly powerful”.

AFAICR, every food product I have seen that has microwave instructions assumes a 1kw oven.

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For me 1200w is minimum.

In my microwave (LG not JennAir) that is where the high voltage transformer sits (and I think in yours as well, given it has an access plate). It’s a step-up transformer to juice the magnetron.

I just looked up that part at RepairClinic (where I get a lot of parts for appliances) and they tend to run a bit under $200 (US) at RepairClinic. JennAir no longer carries the part, which is not unusual for manufacturer’s websites after 10 years.

Just curious, does the control LED still light up? If so, it’s unlikely the main fuse. If it doesn’t light (on the other hand) that doesn’t tell you a whole lot.

Anyway, unless you or partner or someone you know is handy and knows how to short across the capacitor, I’d say don’t monkey with it yourself - even unplugged you can get shocked by capacitor storage.

Up to you how to deal with it but it looks like functional replacements for that microwave itself run over $1K [Edit - maybe less, see P.S. below]. Might consider asking an appliance shop what they’d charge to replace the part, if they’d do it for another couple hundred you’d come out ahead (assuming the transformer didn’t fry the magnetron in the process, but there’s no way to know without someone looking at it).

But if you don’t need the broil and convection features (not sure how often you use them) you’re probably better off simply buying new.

P.S. This “sister oven” looks pretty close to a drop in for what you currently have, KA and JA both being Whirlpool companies. It’s about $700, not sure what shipping would cost you.

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Agree about the instructions. I always have to tailor (reduce time) with mine being 1500 or 1600 watts (can’t remember anymore, plate is on the back, and I’ve got it framed in so not easy to pull it out).

I want to mention here that the fuse that most often blows on a microwave is the one for the control panel. This is a very cheap (~ $20 or less, depending on model) and easy fix.

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Replace for sure. Not only is it likely to be less expensive, but a newer microwave is probably more energy efficient.

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Yeah, I’d assume or hope some improvements to efficiency in the last 10 years. Still, I see it as a bit of a 3-way balance.

Improved efficiency vs. personal threshold of cost to fix/replace (for me, it’s around 50% for something like this, but I can readily see it being much lower for others) vs. landfilling materials which, if the fix/replace balance is acceptable, might not need to be there for another 5-10 years.

This latter admittedly being wildly speculative, but I’ve had microwaves go 20+ years, and others fail too-dead-to-fix at 12.

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I tend to agree with you.

To put MWO wattage into perspective, consider a baked potato. Of course any microwave of any wattage will do the job, but consider the cook times:

microwave conversion chart

Whew! That was close! Good to know. :grin:

You guys have been great! In less than 24 hours!

Every once in a while there’s something easy and cheap to fix, and avoids the landfill conundrum, but sounds like not this time.


I’m the opposite of an advanced MV user. I reheat, melt butter and chocolate, occasionally defrost but basically never cook anything in a MV.
So, I’d probably go for something very basic and easy to operate and to clean, without any extra features or excessive power (1000 W sounds about right).
Additionally, I’d try to make sure it is one of the models which remains discreet when operating and has a door that closes silently enough.


OK, here’s my take: “arcing” + “black spot” = new appliance.