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Sharp Microwave Not Heating: Why & How to Fix? (Explained)

Heating up a cold pizza, making a quick breakfast without gas, warming up milk_ microwave do all these for us. As long as we are in the kitchen, we make use of our microwave one way or another.

So, I understand the concern when you place your cold food inside and set the timer, but the microwave fails to comply. If you own a sharp microwave and face such a situation, try to troubleshoot the core issue yourself instead of calling a mechanic.

Sharp microwave not heating

The reason for Sharp microwave, not heating might be a broken magnetron. When a magnetron is damaged, the fuses are blown, which omits the microwave to heat up. Another reason can be the burning out of the high voltage diode. When the microwave door doesn’t close properly, the device won’t heat.

Usually, when the microwave is functioning but not heating up, the chaos is internal. Some heating elements have either been damaged or burned out due to excess heat.

Troubleshooting will drag the underlying cause and help you to navigate the reason. Sharp microwave provides many models and functions. Here we will discuss two popular models and dissect the reason for not heating up.

Sharp carousel inverter sensor microwave

This model has both inverter and sensor functions. The inverter helps by saving energy and the sensor ensures precise cooking and reheating. Let’s find out the reasons why this is not heating up.

Magnetron failed:

Magnetron generates microwave by heating up and travels through the oven. When the magnetron fails to comply, the fuses are blown which prevents the generation of microwave.

You can check the magnetron with a help of a multimeter. If they don’t read 2-3 ohms, the magnetron is faulty.

Diode burnout:

A microwave oven basically converts the power energy to heat energy. High voltage diode provides power to the magnetron to generate heat.

When the diode burns out, the magnetron can’t receive enough voltage to convert into heat. With a multimeter of 9-volt battery, you can check the continuity of the diode.

Burnt-out capacitor:

With the diode, the high voltage capacitor doubles up the energy output. Together they convert the transformer output to DC voltage.

When the capacitor burns out, the total voltage circuit will be dilapidated. With a VOM meter that has a capacitance testing mode, you can check the capacitor’s usability.

Sharp r259 microwave

Sharp r259 microwave doesn’t have the inverter feature but has sensor to measure the heat quantity. Let’s find out why the Sharp r259 microwave is not heating.

Thermal fuse:

Since the microwave generates an excessive amount of heat within a short span of time, the thermal fuse is installed to ensure the device doesn’t overheat and cause a fire. If the heat gets too much the thermal fuse trips.

When it does, the microwave fails to sense the amount of heat it produces, resulting in not heating up.

Thermo protector:

Thermo protector helps the magnetron to be within the range while generating heat from voltage. If the thermo protector trips due to overheating, the Sharp microwave will fail to heat up.

Door not closed properly:

Sharp microwave has four door switches to function when the door closes. They activate chronologically after the door closes. If the door switch fails, even on of them, the microwave will not turn up to protect the room.

Is it worth fixing a sharp microwave that won’t heat?

It will depend on the result of troubleshooting and finding out the underlying reason behind the Sharp microwave, not heating.

If the issue is fixable, you should fix it and the microwave will resume working like it used to. If the issue is major and unfixable, you should not spend bucks on fixing the broken appliance.

When your Sharp microwave is new, the issue can be resolved by replacing the faulty part of the device.

The replacement will start from $100 and will go up depending on the part’s price and replacement charges. It is still worth it considering the microwave’s price.

However, if the model is old enough and the non-heating issue is repeated from time to time, you should not bother replacing the parts. If the main control board turns out to be defective, replacing the whole oven is advisable.

How do I know if my sharp microwave fuse is blown?

If the Sharp microwave stops heating suddenly, the reason might be a blown fuse. Before repairing or replacing, you need to cross out the possibility of the fuse being blown. The good news is you can check the fuse by yourself. Let’s find out how_

Unplug the microwave:

Before you start navigating, it is important to unplug the appliance to resist any probability of shock. Also, wear rubber gloves because the power residue might still linger even after unplugging.

Locate the fuse:

Sharp microwave did not place their fuse in easy locations. You have to remove the panels and dissemble the heating elements. If you follow the power cord lining up inside the panel, you can locate the fuse. The fuse should be 1-2 inches in length and made with ceramic or glass filament.

Check the fuse:

If the fuse is glass-made, you can easily tell whether it’s blown or not. It will have scorch marks, dark shadows, and melted filament.

When it comes to ceramic fuse, you have to test with an ohmmeter or tester from continuity. If the reading is infinite, the fuse will be deemed blown. But if it read 2-3 ohms, the fuse is operating.

How much does it cost to replace the magnetron in a sharp microwave?

If the magnetron of your sharp microwave is blown, there is no option for repairing it. The only viable thing you can do is replace it.

Replacement will cost you $100 to $200. If the microwave is a countertop, the average cost will be $150. If the oven is built in, the charges will rise a little.

The magnetron will cost from $50 to $100 depending on the model. The labor cost will take the rest of the budget. However, if your model is newly bought, you can use your guaranteed card for free replacement depending on the agreement.

Since replacing the magnetron is risky and not a job for noobs, you should definitely hire a professional.

It will be better if you hire the professional from the sharp outlet since they are better accustomed to their products. Also, check your model number before purchasing to ensure compatibility.

How to fix a sharp microwave not heating?

If the sharp microwave is not heating, first you need to diagnose the underlying cause. Sometimes the issue might be silly and fixable, sometimes you might need help from an expert or professional.

But first, cross off the probable and fixable issues of not heating by fixing it yourself. Let’s see how you can fix your sharp microwave that is not heating.

Check the settings:

Often the microwave fails to warm up our meal due to faulty function we set by ourselves, like timer, clock, or mode. Or if we put something not microwavable at the first place, the appliance will certainly fail to comply.

Reset the CPU:

You can reset the main board or cancel the recent programming function in a sharp microwave. The easy step is to tap the Clear or stop button a couple of times.

Make sure the CPU is not in lockout:

Since the Sharp microwave offers a feature that prevents children from using the microwave with a lock system, this might get turned on. To cancel the program, hold the Clock button, then 1, and tap the start button for 3 times.

Cancel the demo mode:

Demo mode is designated for telecasting the features and functions without actually heating the food. If the model is in demo mode, cancel it by pressing Clock, next 0, then tap stop for a few seconds.

Disconnect the power supply:

The sharp microwave doesn’t have any designated reset button for the CPU. However, you can do it manually by disconnecting the appliance for few minutes. It will provide time for the CPU to reset.

Check the fuse:

If the programming is all okay but the issue is not resolved check whether the fuse is blown or not. Unscrew the panel and replace the fuse if it has blown.

Final Thoughts:

The reason for not heating up the Sharp microwave can be something silly like_ malfunctioning the program, setting the wrong mode or timer, or door switches being nonfunctional. If not, maybe some parts, like the fuse, magnetron, or capacitor, can be blown. Troubleshooting will reveal the reason.