Question about Maytag MMV4205 Microwave Oven

2 Answers

MICROWAVE WILL NOT HEAT

28 month old. MMV4205AAW MAYTAG MICROWAVE. WILL NOT HEAT AT ALL. all switches,capacitor,transformer,over loads are ok according to the help page i used in testing using my digital multimeter. every thing lights up . turn table ratates. all other functions seem to work fine. Gary L.

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  • chacheebluee Sep 15, 2008

    Our microwave lights ups, the turn table turns and it acts like it is working until you take out your food and it hasn't been heated at all. Then one time it will work! Can't have a moody microwave...

  • bmore_bill Oct 12, 2008

    The microwave was blowing the circuit breaker (garage) last month and did it a few times thereafter same day. Then worked until this week. Lights/clock work, but it makes a much louder noise and doesn't heat at all. Should I replace the magnatron, the transformer, a diode(?) or other? Are these easy to pop out the old and reattach the new? Many thanks.

  • William Miller
    William Miller May 11, 2010

    Does it hum louder than before?

    Is the high voltage diode shorted?

    Are the connections on your magnetron burned or melted?

    What's an "overload"?

    There should also be a "mini-manual" or tech sheet hidden inside the unit behind the control panel, which is very helpful when troubleshooting.

    Is that what you mean by the "help page"?

    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.h...
    http://www.gallawa.com/microtech/mag_tes...

    Please clarify.


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23 month old. MMV4205BAS MAYTAG MICROWAVE. WILL NOT HEAT AT ALL. Lights work, turn table rotates, blower works. Everything else seem to work fine. Haven't done any troubleshooting.

Don H

Posted on Sep 06, 2008

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Check the connections on the h.v side because the unit works on 4500 volts and if there are any bad connctions it will not reach its working voltage and will not energize.remove all the connections 1 at a time and tighten all the terminals and try it again.you will not be able to test the components with a digital multimetre as it does not have the range.you need an analoge unit with a 10k scale and a 9 volt battery inside or it will give you falsr readings.teh diode which is thge little black unit with 1 side down to earth should read half way with the laeds on 1 way then when you put it on the opposite side it should not move.the capacitor will make the needle of the multimetre flick up when put onto the terminals both ways.the magnetron should have a short reading on the terminals but with 1 connected to the terminal of the input and 1 to the case it should not read at all,hope this helps regards les

Posted on Aug 01, 2008

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I have panasonic nn-gs597m microwave its working normal but not heating, I opened the cover magnetron is hot the fan is working. Any help?


follow the next steps , use the VOM 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. A regular meter with a diode checker will not work to check these diodes. You have to use a meter with a 9 volt battery or put a 9 volt battery in series with the diode to check it.


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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. When a high voltage transformer fails it will usually arch and have a burning smell.





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 a faulty door switch or within the high voltage circuit; either the high voltage capacitor, diode, transformer or magnetron.

Jun 16, 2013 | Microwave Ovens

1 Answer

Cook temp not working


follow this steps and test with VOM. 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. A regular meter with a diode checker will not work to check these diodes. You have to use a meter with a 9 volt battery or put a 9 volt battery in series with the diode to check it.

Enter your model number to see parts for your microwave.

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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.

Enter your model number to see parts for your microwave.

Help me find my model number
picunavailable175.jpg

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.

Enter your model number to see parts for your microwave.

Help me find my model number
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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.

Enter your model number to see parts for your microwave.

Help me find my model number
picunavailable175.jpg

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. When a high voltage transformer fails it will usually arch and have a burning smell.

Enter your model number to see parts for your microwave.

Help me find my model number
picunavailable175.jpg

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.

Enter your model number to see parts for your microwave.

Help me find my model number
picunavailable175.jpg

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.

Enter your model number to see parts for your microwave.

Help me find my model number
picunavailable175.jpg

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 a faulty door switch or within the high voltage circuit; either the high voltage capacitor, diode, transformer or magn
f4fd5faa-21c8-45e8-aa7c-40b3fa27c1ba.gif

Apr 02, 2013 | Maytag MMV4184A 1000 Watts Microwave Oven

1 Answer

Maytag 4205baw runs but does not heat any items


Step 1:

Follow this steps and see the diagrams.God bless you

1)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. A regular meter with a diode checker will not work to check these diodes. You have to use a meter with a 9 volt battery or put a 9 volt battery in series with the diode to check it.

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 testin

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. When a high voltage transformer fails it will usually arch and have a burning smell

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.

Step 2:

2_6_2013_8_52_10_pm.gif

Step 3:

2_6_2013_8_52_54_pm.jpg2_6_2013_8_53_16_pm.jpg

Feb 06, 2013 | Microwave Ovens

1 Answer

Sharp micro doesn't heat


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.
10_3_2012_5_04_17_am.gif

Oct 02, 2012 | Sharp Microwave Ovens

1 Answer

Maytag microwave problem everything seemingly works but does not heat. Help


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.


10_1_2012_10_10_06_pm.gif10_1_2012_10_10_34_pm.jpg

Oct 01, 2012 | Maytag MMV4205 Microwave Oven

1 Answer

Heating problem


see this causes and fix it. God bless you
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.
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.
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.
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.
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.
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.
9_27_2012_10_25_24_pm.gif9_27_2012_10_25_53_pm.jpg

Sep 27, 2012 | Microwave Ovens

1 Answer

Chefmate microwave will not heat up anything


A microwave not heating up is caused by one or more of the following -

1) Failed controller board (unlikely if you are getting a clock readout and you can get the various functions to work, just no heat)
2) Failed door switch
3) Failed thermal fuse, when used
4) Blown power fuse that is dedicated to the microwave circuit
5) Bad diode
6) Bad capacitor
7) Bad magnetron
8) Bad transformer

Door switches insure the microwave circuit will not engage when the door is open. Slamming the door of the microwave is hard on the switch.

The thermal due is wired into the microwave harness, and is a melting allow type, based on heat buildup within the oven. Always replace with a fuse of the same thermal rating.

The power fuse is a special type and should only be replaced with that same type and rating. It is easily tested.

The diode is a relatively inexpensive part, and is not easily tested. If a grumble is heard coming from electrical area of the unit, then the diode could be shorted.

A shorted capacitor will blow the fuse immediately. And open capacitor will cause a "no heat" condition.

A bad magnetron will also cause a low level hum or grumble from the transformer. But is may also cause no other identifiable symptom of failure.

A bad transformer will exhibit a grumble or hum, and may or may not blow the fuse. But be careful here, the secondary of the transformer produces very high voltages, up to 2.5Kv. Few people own a meter capable of measuring such voltages.

Service and repair of microwave ovens is dangerous work. If you don't know what your doing, DO NOT ATTEMPT TO SERVICE A UNIT WITHOUT INSTRUCTION.

Feb 04, 2009 | GE Spacemaker JVM1640SJ Microwave Oven

1 Answer

LG MS-2143RSL MICROWAVE OVENT NO HEAT


hi i am suggesting that it is probably the magy as the res to grndis a bit low and therefore loading the sec supply down , just a thought
cheers grant

Oct 23, 2008 | LG LRM1250 Microwave Oven

2 Answers

Function of thermostat-switch


We have *critical* safety, disassembly, and troubleshooting info at our
site, and our link is at our listing here on FixYa:
http://tinyurl.com/yzjozk

Once you\'ve looked those over, here are some links on part testing:
http://www.microtechfactoryservice.com/cap_test.html http://www.microtechfactoryservice.com/diode.html
http://www.microtechfactoryservice.com/mag_test.html
http://www.microtechfactoryservice.com/xformer.html

You can usually find helpful exploded view diagrams and order parts by
entering your full model number here: http://tinyurl.com/gv383
We\'re happy to help and we appreciate your thoughtful rating of our answer.

Jan 08, 2008 | Maytag MMV4205 Microwave Oven

1 Answer

Microwave won't heat.


Magnatron is suspect. Need to put a voltmeter and see if the input (primary) side to the high-voltage transformer (big heavy iron thing in there) is getting 120Vac. Don't touch the other (high voltage) side of this transformer. If the power is there, you are looking at replacing the magnatron. Its affordable if you do it yourself - buy the part on EBAY - lookup "universal magnatron"

Dec 30, 2007 | Maytag UMV1152BAS Microwave Oven

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