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Thread: Sharp Microwave oven Model R-330J(S) loose conectio ribbon cable

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    Default Sharp Microwave oven Model R-330J(S) loose conectio ribbon cable



    Hi

    Yesterday I tried to clean my Sharp Microwave oven Model R-330J(S) from two small cockroaches were in the display (microwave was working).

    After cleaning and when I tried to put every thing back together I realized that connection between the ribbon cable and the display is loose and when I tried to power it on, no digit numbers appeared in the display and no light as well.

    Now I am looking for fix that lose connection what type of glue should be used to fix that issue.

    Microwave was working before I cleaned it and there is no soldiering used for the connection above. It is type of glue or adhesive materiel

    Thanks



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    Senior Member iwacelect's Avatar
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    If it's the same as the r350, then it'll be heat and pressure, we used to use a flat steel angle with heat applied (soldering iron on a blob of solder) and press down and drag across end of FCC that's become loose.

    Not easy but sometimes fixed the issue, otherwise it's the 2 pcbs complete, and for that may as well get a new unit, $100's
    When I explained to the guy what avatar I wanted, that wasn't what I meant!

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    Hi iwacelect

    I will explain my problem in details

    I have a Sharp Carousel microwave model R-330J(S) and cleaned two small cockroaches out of the front display.

    Removed, cover, front display/keypad, disconnected all wiring, removed circuit board from front cover, please see the picture below, please see the picture below





    I reassembled it but the ribbon (third picture from the top) cable from the keypad has no connector and I assume is placed between the board that it needs to touch and the rubber guard (i.e rubber strip with the carbon looking center line ,first and second pictures from the top) from the display but I can't get it right,,,the problem I didn't take picture before I disassembled it

    I tried different scenario but most of all keypad was not working I assume its to do with the way this ribbon connector is sitting, as the keypad was not faulty prior to me pulling it apart.

    How can I re-assemble this correctly ? everything else looks fine its just the keypad that isn't working.

    Thanks
    Last edited by zillah; 23-04-12 at 03:42 AM.

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    Senior Member Studio1's Avatar
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    Those elastomer connectors (the white rubber thing with the black centre) are normally used to connect LCD displays to PCBs. There's usually two - one at each side of the display.
    It seems Sharp may have progressed to using them as keypad connector bridges as well now.

    It might be hard to see, but the black part is made up of individual 'conductors'.
    That is, if you start at one end of that strip, there is a conductive section, then an insulator, then a conductive section, then an insulator, and so on.
    It's important that the conductive sections line up with the conductive strips on the ribbon that comes from the keypad.
    They also need to line up with the soldered pads on the PCB (on the other side).
    If they don't, then the keypad won't work.

    You may have to jig around with it a little to get it in the right position. You can use a multi-meter to check the conductive parts are mating correctly with the keypad ribbon.

    IMO, it's not a particularly good way to connect a ribbon cable. The old way, where the ribbon is physically pushed into a mating 'slot' connector is far better, but perhaps more expensive so they've done away with it.
    Last edited by Studio1; 23-04-12 at 07:30 AM.

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    Hi Studio1

    Thanks for your help, I had done many attempts, now I forgot what is the origin connections

    Is there any away I can make sure that I am lying the LCD in the right direction ? I might mess with that ?

    Ribbon cable does it need to be underneath the LCD screen ? or on the top of it ?

    Does the white rubber with the black centre need to be in a specific direction ?

    It might be hard to see, but the black part is made up of individual 'conductors'.
    Yes

    They also need to line up with the soldered pads on the PCB (on the other side).
    Noted

    The old way, where the ribbon is physically pushed into a mating 'slot' connector is far better,
    Yes I love it, I found Samsung doing that , very easy to reassemble it

    Thanks

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    Senior Member Studio1's Avatar
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    Heck, it's been soooooooo long since I repaired one of these microwaves. They were just coming on the market towards the end of the time I was doing microwaves full-time.

    Anyway, from the looks of it you're heading in the wrong direction.
    The green ribbon from the keypad doesn't connect to the LCD or anywhere near it.
    It must go straight to the PCB, as it interfaces directly with the microprocessor.

    Looking at the bottom picture, there's a row of solderpads next to your thumb. This is where the white elastomer must connect to.

    Below those solderpads (and just above the transformer symbol) there appears to be a slot(?) with solder pads above and below it.
    Without being able to see it any clearer (or closer) I'd say this is where your ribbon cable needs to slot in.

    Getting the LCD right is not super hard. It can only sit in the front escutcheon one way. The other way either won't fit or won't look right.
    The elastomer fits into that slot in the plastic shroud and when everything is screwed back together, the PCB pushes firmly against the elastomer which is sandwiched between it and the LCD.

    A good thing to do is carefully clean the edges of the LCD glass where the elastomer presses against it with isoprop and a cotton bud.
    Also clean the edges of the elastomer with the same, before you assemble it all.

    If the display still doesn't show anything, it's back to front. The white elastomer is not direction-specific. It's symetrical so it will work regardless of which way it's put in.
    Last edited by Studio1; 24-04-12 at 05:45 PM.

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    Thanks Studio1

    the elastomer presses against it with isoprop and a cotton bud.
    I used a solution that is used to clean a laptop's screen or desktop monitor.
    I have got concentrate isoprop which I believe it has to be diluted with water 1:1

    Looking at the bottom picture, there's a row of solderpads next to your thumb. This is where the white elastomer must connect to.
    Yes.

    The elastomer fits into that slot in the plastic shroud and when everything is screwed back together, the PCB pushes firmly against the elastomer which is sandwiched between it and the LCD.
    Yes

    The white elastomer is not direction-specific. It's symetrical so it will work regardless of which way it's put in.
    Cleared one confusion that I have

    Getting the LCD right is not super hard. It can only sit in the front escutcheon one way
    This is one of the confusion that I have been experiencing I couldn't figure out which way should I put because it can be fitted in two ways.

    The other way either won't fit or won't look right.
    I couldn't figure out.

    The green ribbon from the keypad doesn't connect to the LCD or anywhere near it.
    It was connected to LCD when I first opened it and it happened I cleaned the same microwave one year back and the green ribbon cable does connect to LCD.

    Ribbon cable has glue that holds to the plastic cover underneath it,,,,by the way I am looking for this glue , what type of glue ? because same glue was used to hold elastomer to LCD screen


    It must go straight to the PCB, as it interfaces directly with the microprocessor.
    It is too short to reach PCB.

    Below those solderpads (and just above the transformer symbol) there appears to be a slot(?) with solder pads above and below it.
    Without being able to see it any clearer (or closer) I'd say this is where your ribbon cable needs to slot in.
    Please see the pictures below :



    Last edited by zillah; 25-04-12 at 09:20 AM.

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    Hmmm... interesting...

    Ok - the LCD - if you hold it up to the light, and angle it slightly, when you look across the edge you can see the 'connections'. They're not always easy to see - but they usually look like purple-coloured fingers along one edge. They'll be apparent on one side of the glass only. This is the side that has to mate to the elastomer.

    As for the green ribbon cable connecting to the LCD - got me there. Unless this is some new-fangled way of Sharp doing it, I've never seen this happen before.

    It just doesn't make sense. The LCD requires particular drive signals (which are fed from the micro) to make it display. These signals are totally incompatible with those required to scan the keys on the keypad.

    I'm not saying it can't be done, it just doesn't sit right with me. Unfortunately, I don't have a service manual for this series of ovens, so I can't consult it to see how they're actually doing it, or where that ribbon needs to go.

    I could understand it if the ribbon mates with a section of the elastomer that doesn't go to the display, but from the photos you show, this doesn't seem to be the case.

    Also, the elastomer has to make direct contact with the LCD. If the ribbon was between the elastomer and the LCD, it wouldn't mate properly with the LCD.
    A ribbon cable just wouldn't be flat enough or have the right qualities to keep in conductive contact with the LCD.

    At this stage I can't offer you much more really. I'm at a loss to work out where this ribbon goes.


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    Thanks for your help

    Ribbon cable has glue that holds to the plastic cover underneath it,,,,by the way I am looking for this glue , what type of glue ? because same glue was used to hold elastomer to LCD screen
    I would like to know your experience about glue as well

    At this stage I can't offer you much more really.
    Appreciate your trying to help

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