Connect with us

Microwave schematic

Discussion in 'Electronic Repair' started by Silver Surfer, Apr 3, 2007.

Scroll to continue with content
  1. Folks,

    My searching on Google has come up empty. Do service manuals and schematics
    actually exist for a GE microwave oven JVM1650BH03? If so where might I
    acquire such material?
     
  2. hr(bob)

    hr(bob) Guest

    Most microwaves have a schematic on the inside of the metal outside
    cover.

    H. R. (Bob) Hofmann
     
  3. James Sweet

    James Sweet Guest


    What's wrong with it? Microwaves are pretty much all about the same inside.
     
  4. Unless it's one of the inverter designs, in which case may be
    no schematic available. Troubleshoot like a switchmode power supply.

    Or, of course, the control board.

    So, what is wrong with it? :)

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  5. I've looked at just about every conceivable location inside and outside the
    cabinet but have not located a schematic.

    It's my daughter's microwave. Complaint was that it keeps shutting down
    shortly after starting to heat something. Problem has been around awhile
    but kept getting progressively worse until now it's just about useless to
    cook something.

    Brought it home with me. Tried it out. Worked perfectly quite a number of
    times. Took it apart just to look for something that could be causing an
    intermittent. Found nothing. Put it back together. Oops. Problem back
    with a vengeance.

    Tore it apart again. Checked lots of connections and TCOs with my ohmmeter.
    Examined circuit board with a high intensity light and a magnifying glass.
    Nothing turned up.

    Unplugged the HV transformer primary and put it through its paces.
    Everything worked flawlessly(except the heat of course).

    Connected the HV transformer again. Voila. It's working normally again!
    My concern is that it will go back into the failure mode sooner or later,
    because no smoking gun has shown up.

    When it was acting up it made me suspect that the board was losing power
    because when it shut off the digital display required me to enter the time
    and date just like it does after it's unplugged.

    An aside to Mr. Goldwasser:

    Your excellent article on microwave repair has been an enormous help to me.
    Thanks for sharing your extensive knowledge with the rest of us.
     
  6. Meat Plow

    Meat Plow Guest

    How is the source voltage?
    --
    #1 Offishul Ruiner of Usenet, March 2007
    #1 Usenet Asshole, March 2007
    #1 Bartlo Pset, March 13-24 2007
    #10 Most hated Usenetizen of all time
    Pierre Salinger Memorial Hook, Line & Sinker, June 2004
    COOSN-266-06-25794
     
  7. Underneath I assume? It does sound like an intermitten connection but
    an ohmmeter probably won't find it. Only a really close examination.

    While highly unlikely, check or replace the fuse as well.
    Thanks. :)

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  8. Mr. Plow,

    The source for my experimentation is a household circuit with hardly
    anything else plugged into it. It looks good on the meter.
     
  9. justmanuals

    justmanuals Guest

    I carry microwave service and parts manuals on my site at http://www.justmanuals.com

     
  10. Meat Plow

    Meat Plow Guest

    The source where the oven had problems is what I was after. And with the
    oven running at full power. I've been working with these things for just
    about as long as they were affordable to the general populace and I've
    seen plenty of problems that were caused by a fault in the source voltage.
    Mind you that's not my diagnosis but I just don't put the cart before the
    horse in things that consume considerable current when operating.
     
  11. You are exactly right in pointing out that the source could be a player.
    Power to the microwave drops by about 4 volts when it's going full tilt
    (that is when it decides to work for a while). Certainly a lesser circuit
    could drop by much more than that.
     
  12. One thing I've found very interesting about this problem. During my
    Googling I came across more than a few posts on various sites mentioning
    that their same model microwave was acting the same way as mine but would
    work flawlessly when the screw is removed from the top of the control panel
    and it is kind of cantilevered outward being supported by the two plastic
    tangs at the bottom. All the wiring is still connected, but the panel is
    tilted out at about a 45 degree angle from the case if you can picture this.
    My microwave behaves exactly the same way. It does not fail to work in this
    position.

    Some have posited that a bad magnetron causes this behavior.

    That brings a few questions to mind.

    If it is a bad magnetron, what is bad about it? Does it leak microwaves
    onto the board which then disrupt the operation of the solid state
    components, but only when the board is in its normal position?

    Is the "bad" magnetron causing a disturbance in the power supply which gets
    conducted back into the board and disrupts the functions?

    Are the wires acting as some kind of microwave antenna when the board is in
    the normal position?

    If there is stray microwave energy bombarding the board is there a simple
    way to shield it?

    What explanations do you have for the observed behavior?
     
  13. Noticed something peculiar while wrestling with the microwave this evening.
    My assumption is that the digital display is a vacuum fluorescent type.

    With the board dismounted for close visual inspection I can see two little
    metallic fingers connected to a one of the display's "pads" on the right
    side. The fingers seem to be touching the inner surface of the glass.
    There appears to be an identical arrangement on the left side of the
    display; however, there is a circular blackened area on the inside of the
    window where the left side fingers make contact.

    Would this indicate a problem with the display, perhaps an internal
    flashover, that could be causing the microwave to act as it does?
     
  14. Every VFD display I've seen has a dark area like that. I think it's
    where a 'getter' was used to remove any remaining free oxygen inside the
    sealed glass envelope. You see them a lot on other vacuum tubes, too.
    Basically a metal that oxidizes easily is placed inside the tube before
    it's sealed, then once everything is sealed up it's heated somehow until
    it vaporizes. It combines with any remaining oxygen inside the tube and
    leaves a deposit on the inside of the glass.
     

  15. So, do you actually have the manual, or are you just spamming?


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
  16. OK. That certainly explains what I'm seeing. Thanks for the explanation.
     
  17. justmanuals

    justmanuals Guest

    I''ve got microwave oven manuals in Sharp, Samsung, Hitachi and a few
    other brands.

     
  18. Do they include controller schematics?

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     

  19. You still did not answer the question: DO YOU HAVE THE MANUAL THEY
    ASKED ABOUT? If so, why didn't you post a link directly to the page
    listing it? Otherwise, you are simply another low life spammer wanting
    people to browse your site, while you know damn well that they will not
    find what they need.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
  20. justmanuals

    justmanuals Guest

    I don't know, I never saw the original post.

    http://www.justmanuals.com
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-