We find microwaves in just about every home we enter for service. To most people, however, they’re a mystery. We put our coffee inside, press one or two buttons, and a few minutes later we have hot coffee! Gotta love this technology!
From a DIY appliance repair perspective, when a novice attempts to repair a “not-heating” problem, half-way into the unit they back off because many components inside stand ready to punish them for trying. But, if they have the right knowledge before starting, chances are they might get the thing running again.
For now, I’ll leave the repair talk out of this and review how microwaves work and why never attempt to repair them on your own without expert help.
That said, welcome to Tin Lizzee’s latest article in our Getting Started Series! Today’s article reaches further into microwave technology. How it heats, when it doesn’t, who invented it and when. Great stuff to know!
What Makes a Microwave Work?
Each time you press “start” on the control panel of your microwave, several events take place to heat your food. The main control receives input from pressing the start button and a safety check of the door switches determines if the microwave can proceed.
After initial checks, house power (120 Vac) feeds to the main control where 120 Vac is fed directly to the high-voltage transformer where it’s doubled by the high voltage diode and capacitor circuit before reaching the magnetron. The magnetron produces microwave energy and cooking begins.
This is a simplified description of the microwave process, but overall it should give you an idea of what happens after you press start on the keypad. Many components come together and operate to produce heat. While failure of any one component would shut off high voltage, most times lights and display work, but food doesn’t cook.
Because of the extremely high working voltage of a microwave (approx. 2200 volts), it’s recommended having a working knowledge of safety and follow every step when disabling high voltage.
Inverter Technology in Microwaves
Standard microwave operation lacks a consistent, even heat in the cavity. To circumvent this, Panasonic and GE use inverter technology in some of their models. An advantage of using an inverter in place of a standard high-voltage transformer is when adjusting a cooking cycle power output to 50% for example, it outputs power at exactly 50% of its full, rated power.
A standard microwave achieves 50% power by turning its magnetron on full for approximately half of the set time in the cycle. Due to heat losses within the unit, the microwave averages 50% output, meaning power fluctuates above and below 50% power.
Inverter technology holds the advantage in cooking food with steady heating, and it can defrost food without burning the edges. However, the cost of microwaves using inverter technology is much higher than standard ones, and repair parts cost more, too.
Sometimes I wonder why convection microwaves haven’t caught on yet. They’ve been around a long time, but few are sold. Perhaps the price scares people away. If I had to guess, I would say it’s because microwave cooking never got people excited enough to try it.
Convection cooking in a microwave is nearly the same as in a standard range with convection. They both use fans to circulate hot air around the cavity and bake food evenly. Wait! Bake in a microwave? Yes, that’s what convection microwaves do! Maybe now we know the reason they’re not popular. Your existing range with convection outperforms the microwave in every way, including cooking space.
One last topic about repair. I couldn’t resist.
Typical Causes of No Heat
A non-heating microwave is a huge disappointment and if you don’t have a clue of the reason, you’re more upset. I know how you feel because I’ve been there, too. Most times, the cause is a simple one, but not as easy to fix. Let me explain.
By far, the most common cause of no-heat in a microwave is a failed magnetron pictured here. A simple reason, but a challenge for a novice to fix. Tin Lizzee can guide you through diagnosing this and any other symptom and find out exactly what is causing the issue.
Another common cause of several issues is the door switches. If one or more fail, lights staying on, no heat, not starting, and starting unattended are some of the symptoms you’ll see. As I said earlier, simple reason, but a challenge to fix.
If you go ahead with a repair, we help you through every step, and if needed, our camera sharing app, Virtually There™ shows us in real time exactly what you see. It’s just like being there with you!
Who Invented the Microwave?
The story about how microwaves got their start is funny! In 1945, a man named Percy Spencer working at Raytheon was working on a radar system and microwaves produced from it started melting a Hershey’s chocolate bar in his pocket!
Initial tests were popcorn and yes, an egg. We all know what happened to the egg, right? It exploded!
From there, Spencer fabricated a sealed metal box and tested his discovery with food inside. He verified temperatures in food rose rapidly but didn’t burn the outside. Raytheon filed for a U.S. patent on October 8, 1945. The rest as they say, is history!
If you have any comments to add from your experience with microwaves, please feel free to add them below. Or, if you liked what you read here today, please let us know. As always, we love to hear from our readers!