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Replacing microwave display?

Discussion in 'Electronic Repair' started by Al, Nov 16, 2005.

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  1. Al

    Al Guest

    I have a Sharp Carousel microwave, model R-305EW and
    the timer/display has developed a problem: part of one of
    the LCD-style numbers no longer lights up.

    Is it costly to replace the display on this unit? Is it a
    relatively easy job for a handyguy with average skills?
  2. Maybe just a bad solder connection.

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  3. Guest

    Or, it could be a bad connection from the display to the pwb via the
    ribbon cable that so many manufaturers use.

    Bob Hofmann
  4. Guest

    Or, it could be a bad connection from the display to the pwb via the
    ribbon cable that so many manufaturers use.

    Bob Hofmann
  5. James Sweet

    James Sweet Guest

    The display is probably fine, likely just needs the connections cleaned
    if it uses one of the rubber contact strips, or the solder touched up.
    Read the FAQ on microwave safety, then once you've done that this is
    most likely something you can fix yourself.
  6. Ray L. Volts

    Ray L. Volts Guest

    Tossed my 2-yr old Sharp R425E because of a bad display. The replacement
    display costs more than what I paid for the whole oven!!

    Unfortunately, Sharp (et al) have seen fit to make these displays a
    permanent part of the CPU board -- that is, the flex trace ribbon is bonded
    in such a way as to make repairs practically impossible. Even if you
    _could_ replace only the LCD module, you can't BUY only the LCD module, you
    have to buy the entire display/controller assembly.
    The replacement cost of your display/CPU board is $118.12 from Tritronics.

    Alternatively, if you're a gambler, you can ship your board off for repairs:

    Even if you're lucky enough that only a very simple repair is needed, at
    $32.50 labor plus parts plus shipping... well, which option you choose
    depends on how fond you are of your oven I guess.

    I purchased that R425E because my old oven was a Montgomery Ward which was
    built by Sharp. It lasted 15 years! I was hoping I'd have similar luck
    with a new Sharp, but alas they've also decided to produce junk now.

    So I thumbed my nose at Sharp and replaced it with an Amana (Maytag), which
    is covered with a full 5-year warranty (factory standard, not "extended") on
    the display/electronics. That's 4 more years than most manufacturers offer!
    I hope this means it's designed to last at least twice as long as the Sharp

    Good luck,
  7. Ray L. Volts

    Ray L. Volts Guest

    Sadly, these are not that simple anymore. The display ribbon is glued/taped
    to the controller board. There is no solder -- good contact depends on
    pressure from the ribbon (it's bent in a "U" loop) and the tape pulling from
    the opposing side of the board.
    If you peel off the display cable to clean the contacts, GOOD LUCK getting
    it realigned with the tightly-spaced traces and maintaining good contact.
    Solder can't be substituted for the method used, as the heat will absolutely
    destroy the business end of the display cable.
    In my case, the display started missing a couple of segments, then a bunch
    of them went soon afterward. All the discrete components on the controller
    board tested ok. The controller IC still worked as far as the oven
    functions were concered. The IC itself isn't replaceable (it's the "black
    blob" type), so there are only two options: buy a new board set which costs
    more than the oven or buy a new oven.
    This is a blatant example of a product designed to ward off repairs and to
    have a relatively short lifespan.
  8. none

    none Guest

    I've got a Sharp with the same problem, bad LCD display unit.
    Like you said they want way too much for a replacement. In my case
    nearly 50 bucks just for the crystal module.
    all else works fine on the oven, you just have to push the buttons
    carefully to get whatever time and cooking level desired.( I'll find a
    donor some day with a dead magnetron that'll hopefully have a good
    display. Untill then it's push the buttons slowly and carefully.)
  9. James Sweet

    James Sweet Guest

    Is there room to drill a hole in the board on each side of where the
    ribbon connects? If so you could cut a little block of aluminum, file it
    so it has a ridge down the middle, then thread holes in the ends and
    screw it to the board so the ridge presses on the ribbon and holds it to
    the contacts.
  10. Ray L. Volts

    Ray L. Volts Guest

    Should be room on the later model Sharps. As these are layered boards, be
    careful with the locations of the clamp holes. If necessary, use a plastic
    strip for the clamp, held down with nylon thru screws (or rivets) or plastic
    spacers as feed-thru bushings for the metal screws if the nylons aren't

    From what I've since read on Sharp ovens, problem contacts don't appear to
    be the common failure mode. Still, for those lucky individuals where the
    only prob may be dirty or loose contacts, this is a perfectly acceptable
    fix -- actually, it would be a much superior method over the crummy original
  11. Al

    Al Guest

    Thanks for the various suggestions to my original post.
    Two question: (1) How do I access the display on this model?
    (2) Assuming I don't want the expense of a new board and
    that I lack the expertise to perform some of the procedures
    listed above, what's one "simple" fix I might be lucky enough
    to encounter when I get a look at the display? Dust on the
    ribbon, haha. Thanks.
  12. James Sweet

    James Sweet Guest

    You might have some luck wedging something between the display and the
    board to put pressure on the ribbon, hunk of styrofoam or something.
    Never seen inside that model so I can't offer specific help though.
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