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Sharp Microwave

Discussion in 'Electronic Repair' started by Ray Batig, Feb 28, 2004.

  1. Ray Batig

    Ray Batig Guest

    Greetings,

    I have a Sharp Microwave R-530BS (now R-530ES). The magnetron went bad. I
    took it in fort service and paid for labor since the magnetron was under
    warranty. I brought the unit home and plugged it in. The next morning the
    clock display was missing a lot of segments. I called the repair place and
    was told to unplug for 10 minutes and try again. It didn't help, even
    waiting 8 hours. I dragged it back to them, and everything was fine.
    Returned home and the next morning display was messed up again. The repair
    guy says this happens a lot to them and they test for 4 hours. He said $100
    would buy a new part.

    I looked inside and see that there is a flat ribbon cable between the
    circuit board and the display. The ribbon cable is kinked. Could this be
    where the problem is or is there a real need to change out the parts?

    I see that there are actually 3 parts to this control. First there is the
    power circuit board. This holds the relays etc. Number on it is Sharp
    FB030MR KPC-M-PP ... other side says QKITPB030MRE0. The second part is the
    control circuit board. It holds the clock circuitry and touch panel
    circuitry. Number on it is Sharp FA585DR...Lot No. 0074 B031MR. Last there
    is the display itself. The relay board is connected to the circuit control
    board by a flat ribbon cable (obvious round semi-flexible wires) soldered at
    both ends. The circuit control board is again connected to the display by a
    flat ribbon cable ( obvious flat wires or foil) connection to boards is
    through some other method than soldering. Does anyone know if I can just
    replace the circuit control board and display Vs the total three part
    assembly? Does anyone have a working circuit control board and display for
    sale?

    Thanks in advance for your help and guidance.

    Ray Batig
     
  2. The bottom line is that you didn't have this problem before you had
    the magnetron replaced. Coincidences are unlikely.

    Have you checked for bad solder connections, reseated any plubbable cables,
    etc.?

    If the display is an LCD, there may be "zebra stripe" connectors linking
    it to the PCB. These get dirty.

    --- sam | Sci.Electronics.Repair FAQ Home Page: 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 Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: The email address in this message header may no longer work. To
    contact me, please use the feedback form on the S.E.R FAQ Web sites.
     
  3. Art

    Art Guest

    The Sharp Microwaves have had a lot of failures with the display-controller
    devices used in both their tabletop and under counter models. Only way to
    repair them is to replace the complete controler as a unit.
     
  4. Ray Batig

    Ray Batig Guest

    Thanks to you both. I will try to see if there is something loose. Sure
    sounds like it since things cleared up when I hauled it back to the shop. I
    find it hard to believe that Sharp is using such cheap but over priced parts
    that you can't take the microwave to the shop without the controls failing.
    I will keep you posted on what I find.

    Ray
     
  5. Ray Batig

    Ray Batig Guest

    Greetings,

    I finally got back to being in town and having enough time to do some in
    depth troubleshooting. what I have found is that the flat ribbon cable, foil
    ribbons, between the control circuit board and the LED display must be the
    culprit. When I have the box open and the clock set, then set 8888 I get
    Backward E backward C 1 on the left and nothing in the last spot. The flat
    ribbon cable is in an inverted U. When I rub across the cable which flexes
    it, the unlit segments of the 8888 light up and go off. This cable connects
    to the landing spots on the circuit boards with no apparent solder
    connections. Almost looks like a spot weld. Do either of you, or others
    reading this message know how this connection is made? Can I strip off the
    flat ribbon cable and solder fine wires in its place? Any other ideas?

    Thanks again for your help!

    Ray
     
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