Results 1 to 7 of 7

Thread: Why my microwave is blowing internal fuse?

  1. #1
    Join Date
    Feb 2012
    Location
    Miami
    Posts
    3

    Default Why my microwave is blowing internal fuse?

    Model Number: MH2175XST-1
    Brand: Whirlpool
    Age: 1-5 years

    Hi,my wirpool MH75XST-1 over the range microwave is blowing the internal 20 amp. fuse when i try to use the microwave function only.it doesn't blow this fuse using the fan,lights or display.Any ideas?

  2. #2
    Join Date
    Oct 2004
    Location
    Ontario, Canada
    Posts
    13,646

    Default

    Hi,

    is blowing the internal 20 amp
    When...exactly?
    Opening the door, closing the door, when you press start?

    Q - My microwave went dead when I opened the door ( same problem as closed the door ).
    A - This often is a stuck or faulty door switch and it has blown the interior microwave fuse.

    Q - My microwave blows the fuse inside itself as soon as I push the start button.
    A - Usually a shorted high voltage capacitor...see components section.
    A copy and tip from Prashanth:
    Description of problem (Maytag CMV1100Q) :
    Microwave stopped working while cooking. Replaced a
    20AMP fuse.
    When the cook cycle starts, microwave makes a groaning noise and stops. It loses power since the fuse is blown.

    Solution: High-voltage capacitor shorted. Replaced it and microwave works fine.
    Its located behind the fan underneath the high-voltage transformer.

    Remove the vent fan hood
    Remove the display control panel by removing the screw
    Take pictures of all the connections behind the control panel.
    Unhook all connections
    Remove the connections to fan
    Remove the fan
    Remove the screws and connections for interlocking switches.
    Make sure the high voltage capacitor is discharged!
    Remove the high voltage capacitor and replace
    Retrace the steps and put everything back.

    Microwave works great now.


    jeff.
    http://www.applianceaid.com/
    Appliance Repair Aid

  3. #3
    Join Date
    Feb 2012
    Location
    Miami
    Posts
    3

    Default

    Quote Originally Posted by jeff1 View Post
    Hi,



    When...exactly?
    Opening the door, closing the door, when you press start?

    Q - My microwave went dead when I opened the door ( same problem as closed the door ).
    A - This often is a stuck or faulty door switch and it has blown the interior microwave fuse.

    Q - My microwave blows the fuse inside itself as soon as I push the start button.
    A - Usually a shorted high voltage capacitor...see components section.
    A copy and tip from Prashanth:
    Description of problem (Maytag CMV1100Q) :
    Microwave stopped working while cooking. Replaced a
    20AMP fuse.
    When the cook cycle starts, microwave makes a groaning noise and stops. It loses power since the fuse is blown.

    Solution: High-voltage capacitor shorted. Replaced it and microwave works fine.
    Its located behind the fan underneath the high-voltage transformer.

    Remove the vent fan hood
    Remove the display control panel by removing the screw
    Take pictures of all the connections behind the control panel.
    Unhook all connections
    Remove the connections to fan
    Remove the fan
    Remove the screws and connections for interlocking switches.
    Make sure the high voltage capacitor is discharged!
    Remove the high voltage capacitor and replace
    Retrace the steps and put everything back.

    Microwave works great now.


    jeff.
    Sorry,is doing it when i press the start button and works for 3 seconds before blows the fuse.

  4. #4
    Join Date
    Oct 2004
    Location
    Ontario, Canada
    Posts
    13,646

    Default

    Often a shorted HVCapacitor like mentioned above...
    Ohm testing a cap...
    Testing a capacitor

    jeff.
    http://www.applianceaid.com/
    Appliance Repair Aid

  5. #5
    Join Date
    Feb 2012
    Location
    Miami
    Posts
    3

    Default

    Quote Originally Posted by jeff1 View Post
    Often a shorted HVCapacitor like mentioned above...
    Ohm testing a cap...
    Testing a capacitor

    jeff.
    Thanks Jeff, I tried out the capacitor and everything went well, but when I removed the capacitor I noticed the HV transformer was fried. There was obviously a short there. I’m not sure whether I should replace the transformer or more importantly figure out what caused the short leading to the transformer burning out.

    Here's an image for reference:
    Click image for larger version. 

Name:	Kendale Lakes-Lindgren Acres-20120226-00014.jpg 
Views:	420 
Size:	59.2 KB 
ID:	4295

    I’ve been checking the prices for the transformers and they’re very expensive. My wife mentioned that she was cooking on the stove and there was a good deal of vapor rising up towards the microwave. Do you think it’s possible that the condensation from the vapor could have caused the short in the microwave’s transformer.
    Last edited by adol66; February 27th, 2012 at 12:30 AM.

  6. #6
    Join Date
    Oct 2004
    Location
    Ontario, Canada
    Posts
    13,646

    Default

    Do you think it’s possible that the condensation from the vapor could have caused the short in the microwave’s transformer.
    Possible yes.

    HVTransformers don't go often but when they do we often see them cooked up.

    I’ve been checking the prices for the transformers and they’re very expensive
    A little

    No pic Transformer, h.v. Manufacturer Number 8206343

    jeff.
    http://www.applianceaid.com/
    Appliance Repair Aid

  7. #7
    Join Date
    Jan 2012
    Location
    Nashville, Tn
    Posts
    54

    Default

    High voltage arcs like crazy when the humidity rises, just listen to the power lines when it's foggy out. Most likely the transformer will fix it. but they are not cheap.

Similar Threads

  1. Whirlpool microwave blowing fuse
    By phil25rs in forum Whirlpool/KitchenAid
    Replies: 4
    Last Post: December 31st, 2010, 07:38 PM
  2. thermal fuse keeps blowing
    By chanchamone in forum KitchenAid
    Replies: 2
    Last Post: July 9th, 2007, 10:55 AM
  3. DW blows internal thermal fuse on regular basis.
    By larryr in forum KitchenAid
    Replies: 9
    Last Post: June 6th, 2007, 12:49 AM
  4. Kenmore Microwave Oven Fuse Keeps Blowing
    By Belligerent in forum Sears Kenmore
    Replies: 2
    Last Post: June 7th, 2005, 11:54 AM
  5. Kenmore Microwave Oven Fuse Keeps Blowing
    By Belligerent in forum Sears Kenmore Reviews
    Replies: 1
    Last Post: December 31st, 1969, 06:00 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
If you feel that you have benefited from this site, and would like to show your appreciation, you can throw a buck or two in the Appliance Blog Tip Jar - Thank you!
Facebook Page: ApplianceBlog Twitter: ApplianceBlog Google+ YouTube: ApplianceBlog