Appliance

Need Appliance Repair Help? Ask a Technician for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Appliance

inverter in microwave keeps going bad

Customer Question
inverter in microwave keeps going bad
Submitted: 4 years ago.Category: Appliance
Ask Your Own Appliance Question
Answered in 52 minutes by:
1/1/2013
Appliance Technician: Jon, Appliance Technician replied 4 years ago
Jon
Jon, Appliance Technician
Category: Appliance
Satisfied Customers: 3,646
Experience: Appliance Service Technician with 10+ years experience.
Verified

Jon :

hello

Jon :

i would first make sure the polarity to the outlet the machine is plugged into is good and is not reversed. that is the number one cause for the inverter to blow out

Jon :

check that and if it is good then you have a shorted wire somewhere in the machine. And unfortunately it may not be found but please try taking it down and appart and check it out.

Jon :

get back to me here if you need more help.

Jon :

i see this a lot. and 90% of the time the wiring or outlet is the problem. so if you have a meter or tester, test that first. and if that i snot your problem please come back here and let me know and I will help you more.

Jon :

And if you feel that i have helped to answer your questions please remember to rate my performance positively below with ok service or better rating. And if you feel that i have not helped you enough, please dont rate negatively. just respond back to me here and I will help you more until you are completely satisfied and we can find and solve the problem.

Customer :

I have taken the microwave down and I have been working on it in my basement. I checked the polarity and Im getting 123 volts through the outlet. In addition my house was hit by lightning 2 months ago and I already had to fix my dishwasher(replaced) and washer(repaired). The microwave showed no symptoms and worked fine till now. The code f-9 came on and i took it down and took it apart. The inverter board was fried, it had turned brownish. I replaced it and it was working but buzzing and overheating. Which it buzzed right before it went out the first time. Next thought was maybe the magnetron was going out, so i replaced it. I can get a wiring diagram for the microwave if that would help. But most of the connections in the microwave are dummy proof, considering their all different and can only go where their supposed to. The exception to this is the noise filter, which seems to be where the power cord goes first and is dispersed from there. Could it be a bad control board( the one with the buttons on it)? Or a bad noise filter board? After looking at the wire diagram the juice is dispersed from the noise filter. Also, the exhaust fan and the lights work fine and as intended. So I think it is within the heating section of the micrrowave. Any suggestions?

Jon :

Hello again,

Jon :

the f9 error is for a bad inverter board. which you already know.

Jon :

there are many reasons for the inverter board to fail including but not limited to a bad thermostat, computer, magnetron, diode, and transformer.

Jon :

i can tell you this, if the machine is heating the low voltage side of the microwave is good.

Jon :

and if the inverter board is continually failing you should start by checking the high side of the microwave. which is the magnetron, capacitor, diode, transformer and thermostats.

Jon :

if the inverter board is failing again and you have already changed the mag and inverter it seems to me like the transformer and capacitor has been damaged by the lightning strike or power outage. and that would send improper voltage to the capacitor and transformer which would burn out the inverter board.

Jon :

I must first say that it is extremely dangerous working on microwaves if you are not sure of what you are doing, especially if you have never checked a microwave before like this, please leave this to a professional.

Jon :

even when the micro is unplugged, the cap will still hold a charge of a few thousands volts. and THAT COULD HARM AND EVEN KILL YOU!

Jon :

so please discharge the cap before doing anything else with this machine.

Jon :

then follow the checks outlined in the website below. it will list how to check several components to your microwave.

Jon :

please just copy and paste the link below to your browser to open and view.

Jon :

http://www.appliance-repair-it.com/microwave-repair.html

Jon :

please focus on the high voltage side of the micro and check the mag, diode, cap and transformer.

Jon :

if you have any other questions please come back to me here and i will help you more.

Jon :

please let me know how you make out.

Jon :

thanks

Customer :

I checked the thermostat, according to the manufacturer it should be sitting at 0ohms and it is. I also checked the wiring for any miswiring, or shorts. On the diagnosis sheet that came with the microwave, which was inside it, it said check inverter, if it keeps going bad check the thermostat. If thermostat is reading 0 ohms it should be good and to replace the control assembly board, which has the transformer on it. As far as the diode goes, I would take a guess and say it is also on the control board.

Customer :

And to further answer your statement, this is my first attempt on a microwave, and I am aware of it being able to hold charge, so I do where rubber gloves when working on it, and I always discharge the electricity off of the machine. Can never be too careful.

Jon :

yes. you can never be too careful.

Jon :

the transformer i was referring to is actually a separate part in the microwave. it is not on the computer board. but yes, what you are following is the tech sheet and work flow chart for the voltage in your microwave.

Jon :

if i may ask, how did you check the wiring for any shorts?

Jon :

and the diode is a separate part as well. forgot to mention that above with the transformer. it is inline with the capacitor. it is the piece of metal that gets hooked up to one of the terminals of the capacitor and gets screwed to chassis ground. that too would need to be checked before knowing if the computer board is your problem.

Jon :

all i am saying here is that you must first check these parts before just simply saying the computer board is the problem. I would hate to see you spend more then $150 on a computer if it doesnt fix your problem.

Jon :

and yes, most times when you have this complaint, the computer is usually the problem. and is sending too much voltage to the inverter board causing it to constantly fail.

Jon :

please get back to me here with the full model number of the microwave so i can look up the part info for you. so if you would like to change the parts yourself you can do so.

Jon :

thanks

Customer : I will get it tomorrow
Jon :

you got it. please do and let me know.

Jon :

this way i will look up the model info and get the part info for you

Jon :

talk to you tomorrow

Ask Your Own Appliance Question
Ask Jon Your Own Question
Jon
Jon
Jon, Appliance Technician
Category: Appliance
Satisfied Customers: 3,646
3,646 Satisfied Customers
Experience: Appliance Service Technician with 10+ years experience.

Jon is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Thank you for the expeditious answer. It's good to know you're out there and awake in the wee hours when I finally have time to ask questions about my Jenn Air.

JeanRiverhead, NY

You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future.

JimmyBagley, IA

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

< Previous | Next >

Meet the Experts:

John

John

Home Appliance Technician

13,453 satisfied customers

Appliance repair business owner for over 43 years.

Tom Goellner

Tom Goellner

Home Appliance Technician

1,558 satisfied customers

32 yrs. experience servicing major appliances and HVAC equipment.

Tyler Z.

Tyler Z.

Appliance Doc

83,249 satisfied customers

9+ years being an appliance technician with factory training.

Kelly

Kelly

Appliance Technician

18,456 satisfied customers

Highly accurate diagnostician with over 30 years experience!

The Home Smithy

The Home Smithy

Home Appliance Technician

6,148 satisfied customers

30 years repairing appliances

william

william

Home Appliance Technician

3,012 satisfied customers

Major Home Appliance Technician Specialist Whirpool Certificate

John

John

restaurant equipment technician

2,103 satisfied customers

25+ years experience. I'm now employed by a commercial cooking equipment service company

< Previous | Next >

Related Appliance Questions
I have a ge Profile series range model PCB909SR1SS. The
Hi I have a ge Profile series range model PCB909SR1SS. The cooktop part is not heating up? I have estabilsihed the power supply is Okay. The ooven seems to work okay as it is heating up okay. the cloc… read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
I am trouble shooting my Whirlpool Gold Series dishwasher.
I am trouble shooting my Whirlpool Gold Series dishwasher. The control board appears damaged. I need to know where the fuse is to check that as well, … read more
Joel Swenson
Joel Swenson
High School or GED
3,311 satisfied customers
Light is on but dryer will not come on mod: keys700jqo,
light is on but dryer will not come on mod: keys700jqo … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
My Fridgidaire 12 year old electric oven stopped working,
My Fridgidaire 12 year old electric oven stopped working, but the stovetop is working fine. I can set the oven and broiler temp/hi-lo, but no heat. Do they stop working as a set? Or coincidentally the… read more
Kelly
Kelly
Appliance Technician
High School or GED
18,456 satisfied customers
Our oven will not heat at all. Let me get the paper. It
The fans work in the oven but it never gets hot. All the burners work fine… read more
travis webb
travis webb
tech.
2,236 satisfied customers
Washer stopped mid cycle - screen reading Ld and no
washer stopped mid cycle - screen reading Ld and no functions respond? … read more
Joel Swenson
Joel Swenson
High School or GED
3,311 satisfied customers
I have a GE Profile Fridge PSS26SGPA Both Fridge and Freezer
I have a GE Profile Fridge PSS26SGPA Both Fridge and Freezer quit No longer cold … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
Center panel heated up ,on my side by side ,model is
center panel heated up ,on my side by side ,model is vd243013 … read more
Kelly
Kelly
Appliance Technician
High School or GED
18,456 satisfied customers
I have a kenmore stove modeland oven doesn't heat. Worked
I have a kenmore stove model(###) ###-####and oven doesn't heat. Worked fine last night. Stovetop works fine … read more
Joel Swenson
Joel Swenson
High School or GED
3,311 satisfied customers
I have a viking range and have problems with the right side
I have a viking range and have problems with the right side of the slide in stove. They flash when I have my pot on the element and then it stops the magnets do not seem to stay. I had a repair person… read more
Rusty S
Rusty S
Technician
84 satisfied customers
Have a Dishwasher (model SHX43P16UC/60) that turns on and
Have a Dishwasher (model SHX43P16UC/60) that turns on and starts pumping before I close the door to start a cycle … read more
Kelly
Kelly
Appliance Technician
High School or GED
18,456 satisfied customers
I have whirlpool duet model WFW91950WW00 not putting out
Good Morning; I have whirlpool duet model WFW91950WW00 not putting out enough cold water. Whats the Ohms of resistance range on water valve supposed to be in?… read more
Whrlp Master Tech
Whrlp Master Tech
Vocational, Technical or Trade Scho
4,977 satisfied customers
My refrigerator went out today, the electricity is still on
My refrigerator went out today, the electricity is still on but there is no cooling. … read more
Rusty S
Rusty S
Technician
84 satisfied customers
We have a Samsung fridge freezer - model number SRF752DSS in
Hi we have a Samsung fridge freezer - model number SRF752DSS in storage for 6 years. It is now plugged in but not cooling. It is missing a Aqua pure plus filter, which I am going to order. Would this … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
How do you remove th display panel on a Samsung
How do you remove th display panel on a Samsung Rfg298hdrs/xaa. I have a new display board to put in. … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
I have an error message )xx1. The first time today it is
not that i can tell initially it has a reset command i did that then it came up with error message and to call jennair… read more
Joel Swenson
Joel Swenson
High School or GED
3,311 satisfied customers
I cleaned my oven and now there is an error code about the
I cleaned my oven and now there is an error code about the "meat probe". How can I reset it? … read more
Tyler Z.
Tyler Z.
Appliance Doc
Bachelor's Degree
83,249 satisfied customers
Our dishwasher doesn't go thru the cycles it starts and it
our dishwasher doesn't go thru the cycles it starts and it drains but it just keeps running if you start it … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x