How is the diode connects to a capacitor in a maytag microwave mmv5165aas?

Replace the faulty door switch.

see this causes and fix it. God bless you
Diode The high voltage diode converts the A/C power output of the transformer to D/C, doubling the voltage to nearly 5,000 volts. This high voltage powers the magnetron which emits the energy that cooks the food. If the diode burns out, a lower A/C voltage reaches the magnetron, which is not sufficient to power the magnetron. When the diode fails it is often visibly burned out. If it appears to be good, it can be tested with a volt-Ohm meter capable of testing diodes. High voltage diodes frequently fail and are one of the most common points of failure in a microwave oven.

Door Switch If the microwave does not heat, one of the door switches might be defective. Microwave ovens normally have three door switches, if any of them fail the microwave does not turn on and does not heat. Check the switches for continuity with an Ohm meter.

Magnetron If the microwave oven doesn't heat the magnetron tube might have burned out. The magnetron uses high voltage, high current DC power to generate the microwave frequency that cooks the food. If the microwave oven is turned on when it is empty this can cause the magnetron to burn out. Once it is burned out it has to be replaced, it's not repairable.

High Voltage Capacitor If the microwave doesn't heat the high voltage capacitor might be defective. The high voltage capacitor works with the high voltage diode to convert the output of the transformer to DC voltage and to double the output voltage. If the capacitor is burned out the entire high voltage circuit stops working properly. The high voltage capacitor can be checked with a special VOM meter which has a capacitance testing capability. Be aware that the high voltage capacitor can retain a charge of more than 3,000 volts and can injure or kill a person if not handled properly. Only trained technicians should perform this type of testing.

High Voltage Transformer If the microwave does not heat, the high voltage transformer might be burned out. Microwave ovens produce a very high voltage in order to power the magnetron antenna, which emits the energy that cooks the food.

Thermal Fuse If the microwave doesn't heat the thermal fuse may have blown. It can be tested for continuity. Watch our fuse testing video for more information.
Thermoprotector If the microwave doesn't heat the thermoprotector may have tripped. This is a safety device to prevent the microwave from overheating. It can be tested for continuity to see if it's blown.

Main Control Board If the microwave doesn't heat the main control board may be defective. This is not common. When a microwave doesn't heat the problem is usually within the high voltage circuit; either the high voltage capacitor, diode, transformer or magnetron.

Open microvave compartment and you can physically see the burnt transformer or capacitor or diode.make sure to discharge capacitor before you start your work
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Hello,

Investigate these three areas if your microwave won't heat food and you hear a loud buzzing or humming noise.

Power Diode

A diode is an electronic component that readily passes current in one direction only and blocks the flow of current in the opposing direction. If your microwave's diode has become defective, your microwave will not heat and you will hear a buzzing noise. Test the diode to determine if this is the cause of your problem. Replace it if it is defective.

Testing a diode

NOTE: Before you test your diode, make sure your microwave is unplugged, and that you discharge the microwave's capacitor.

Whether it is shorted or open, a defective diode will most likely show some sign of defect. Defective diodes will usually emit an electrical burning smell, signifying its defectiveness. Also, it may have split in two, or it may exhibit a burned crack, or possibly even a blistered spot.

A shorted diode is indicated by a loud humming noise from the high voltage transformer, and no heat produced when a cook cycle is initiated. Whereas little or no heat produced in your microwave, with an absence of a humming noise is indicative of an open diode. In either case, the diode has to be replaced.

With your microwave unplugged, and your capacitor discharged, use extreme caution to remove the lead that leads to the capacitor. You can leave the ground connection attached. The side of the diode that goes to the ground is usually marked with a dot, stripe, or arrow. Set your ohmmeter to R x 10,000 or higher. Touch the positive meter probe to the anode and the negative meter probe to the cathode to measure the resistance across the diode terminals. Remember that the cathode is on the side that goes to the ground, which is often marked by a dot, stripe, or an arrow.

A normal diode, that is a non-defective diode, will read anywhere from 50,000 to 200,000 ohms. Differences in microwave make and model account for this large range in resistance readings.

Reverse the meter probes and measure resistance while touching the positive probe to the cathode and the negative probe to the anode. Reversing the probes like this should result in a reading of infinity. Unless a bleeder resistor is present. The presence of a bleeder resistor would produce a reading of the value of the resistor.

High Voltage Capacitor

A capacitor is an electrical device which stores electricity. A defective capacitor may be why your microwave is not heating but you are hearing a buzzing or humming noise. The capacitor will have to be tested to determine if this is the cause of your problem. A defective capacitor will have to be replaced before your microwave will work again. Make sure you discharge the capacitor before you test it, though.

Magnetron

A defective magnetron is the third possible cause of why your microwave is not heating, but you can hear a buzzing noise. Test your microwave's magnetron. Replace it if it is defective.

Testing a magnetron

NOTE: Before you test this component, make sure your microwave is unplugged, and that you have discharged the capacitor.

There are two tests to conduct in order to determine whether or not a magnetron has become defective. If you receive results other than what are detailed below, you will have to replace your microwave's magnetron. Each test is described for you here:

TEST 1: Locate your magnetron and label each of the wires attached to it so that you know which wires are to be replaced where. Set your ohmmeter to the lowest resistance scale. Take a resistance measurement between each of the magnetron's terminals by touching each probe to one terminal each. Reverse the probes and take a second resistance measurement. Each measurement should read less than one ohm.

TEST 2: Set your ohmmeter to its highest resistance scale. Touch one of the meter's probes to a magnetron terminal. Touch the other probe to the metal magnetron housing. Take special caution to not touch the two probes together. This could result in an inaccurate reading. This test should produce a reading of infinity - indicating an open circuit.

Read the tips on the below links on how to replace your microwave oven's diode and how to discharge the capacitor.

http://www.fixya.com/support/r7088355-replace_microwave_ovens_diode

http://www.fixya.com/support/r7088317-discharge_microwave_ovens_capacitor

I hope the above is helpful.

Regards.
Walesarumi

A capacitor generally causes the buzzing sound. Look for the buzzing part or a buldging top on a capacitor

Benjamin

check the high voltage diode inside the unit,its connected to one leg of the high voltage capacitor and the other side to the metal shell of the unit,if this opens you don't get the high D.C. voltage necessary to operate the magnetron,be careful,the capacitor can store up to 2100 v.a.c.so discharge it first to be safe

The magnetron is a tube with a heater/cathode element in the middle of a series of scallop-like grooves that surround the cathode, but spaced away from the cathode. A small, insulated wire protrudes into one of the scallops and extracts the microwave energy that passes down the wave-guide, past a fan-like device called a stirrer that scatters the energy just before entering the cooking cavity.The magnetron requires a low voltage/high current AC heater supply plus a 3000 to 5000 volt DC supply that is hooked to the cathode of the magnetron. The transformer supplies both voltages as AC waveforms. The diode makes the HV AC supply into HV DC by passing current in one direction only and the capacitor stores/smooths that HV DC into relatively stable DC for connection to the cathode of the magnetron. The other side of the DC supply is tied to case ground as is the outer case of the magnetron. This arrangement is typical of all microwave ovens (and radars).

Normally if no power is indicated, it is due to a blown fuse but if fuse has blown be careful, it because there is something wrong. Mostly its due to a problem in the power circuit.Can either be the magnatron or the diode capacitor combination.Normally the capacitor goes faulty causing the HV diode to blow. Replace the two components(diode and cap.). If it happens again replace the magnatron. Microwave truely dangerous and needs proffesional att. email me if you want to go ahead yourself
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A failed diode isn't the most common failure, but it happens. And sometimes it's due to bad magnetron or a bad connection.

If the capacitor fails, it almost always shorts, which results in a blown fuse whenever you hit "Start" to run the microwave.

The magnetron on this model should have a 5-year warranty, in case that's relevant. Your owner's manual is here.

We have the service / repair manual for this model and have uploaded it to our site here to help you.

It will give you safety info, step by step help in disassembly, troubleshooting tips, and part numbers.

Here are some links you or someone you know can use for test help, but read their safety warnings first:

http://www.gallawa.com/microtech/diode.html
(if it's not shorted or burned, it's probably okay)

http://www.gallawa.com/microtech/mag_test.html

http://www.gallawa.com/microtech/xformer.html

http://www.gallawa.com/microtech/cap_test.html

There should also be a "mini-manual" (tech sheet) hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting, testing, and locating components.



At our Web site, we have a video available showing how to remove a typical over the range control panel assembly in under 5 minutes.

You can find helpful exploded view diagrams and order parts here.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

If it is under warranty, call service. I experienced similar odors, sounds, and failure to heat meals. The magnetron/emitter and the transformer are replaced on two separate failures. Now the third time just happened. I am afraid mine is out of warranty and I will not purchase Maytag again.