Latitude E7240 (TOUCH) LCD lid/hinge disassembly question

Discussion in 'Dell Latitude, Vostro, and Precision' started by WindowsRevenge, Mar 4, 2019.

  1. WindowsRevenge

    WindowsRevenge Notebook Enthusiast

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    Hi all,

    So I purchased a used E7240 perhaps 10 months ago. Got it at a pretty good price at the time ($220 USD), has touch, 4600U, 8GB, SSD, fingerprint, backlit keyboard, etc. Battery ok, not great but not a dud either. I think was good for the config/price. It was in fairly good physical condition though when I got it the wifi card was burnt out--it was working but didn't get any signal at all. Easy enough to replace with an Intel 6205N I had lying around (though I want to replace it with a ac wifi/BT card since it doesn't have BT otherwise) and I didn't bother complaining to the seller about it.

    Anyway because I also have an E6320 which has served me well for several years I never really used the E7240 much. When I got it the hinge was fairly stiff/sturdy but after I started using it a bit more it became very loose all of a sudden and would just flop around. I figured out fairly quick it's not really the hinge but the LCD cover on the one side is like cracked open/apart so the hinge actually pops out of where it's supposed to be and doesn't turn with the lid. I can pinch it back together but it always just pops out again unless I pinch/hold the corner every time I move the screen.

    It seems like it shouldn't be hard to fix but I don't understand how the top cover is held to the monitor--does it snap together, is it glued, or does it have screws? The problem I have in figuring this out is I have the touchscreen version of the laptop and strangely enough all the instructions online to dismantle the top lid are for the non-touch model which tells you to pry/pop off the bezel. Even Dell's own service manual doesn't seem to indicate how the touchscreen model's screen comes apart from the lid. Because it's capacitive touch the digitiser is presumably bonded to the screen and there's no bezel that comes off like on the standard screen version!

    How does the screen separate from the lid/cover on the touch model? Or is this not supposed to come apart at all on the touchscreen?

    Any help would be appreciated, I'd really like to fix this annoying issue!
     
  2. ALLurGroceries

    ALLurGroceries   Super Moderator

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    There's one way to find out... take a prytool or guitar pick and see if you can get any separation. On a touch model it would be the bezel/digitizer/glass layer that you're prying off, and the LCD would be glued onto that as one assembly, and on the other side the lid which the hinges are attached to.
     
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  3. WindowsRevenge

    WindowsRevenge Notebook Enthusiast

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    Hmm well I don't exactly waat to make it worse/break it. I'm definitely not messing around with the digitiser either as that would just be a recipe for destroying the screen.

    From the "upgrade your E7240 screen" thread it seems like anyone switching to the FHD/touchscreen is buying the entire screen/lid assembly. So I'm guessing it is indeed not supposed to come apart. I wonder then, how mine has come apart near the hinge? I'm guessing the hinge "pressure" from opening/closing all the time split it apart there.

    My only issue now is...how would I fix it? it seems like it would be hard to get any glue or epoxy in there to try to bond it together and I'm unsure if that would be strong enough anyway. Is this glued together to begin with or are there screws that can't be accessed w/o separating the digitizer? I'm really going to hate leaving it like this because it's quite annoying TBH and at any random time the screen will just flop right open or closed with a little movement :( Surprisingly the one hinge being good on the left side isn't enough to hold the entire lid firmly whenever the right side splits apart in the corner.
     
  4. ALLurGroceries

    ALLurGroceries   Super Moderator

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    Is there any kind of seam on the side of the lid?
     
  5. WindowsRevenge

    WindowsRevenge Notebook Enthusiast

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    Yeah I mean there's a seam all the way around it, it's just that it's sealed/secure everywhere but split in the bottom right side near the hinge--I can squeeze it back together but it will just pop back at random and then the lid moves independently of the hinge and, as said, the other side isn't enough to support the screen/lid weight on its own.

    A bit tired now but I'll try to take a pic tomorrow if that explains it better.
     
  6. WindowsRevenge

    WindowsRevenge Notebook Enthusiast

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    Well, unfortunately this problem has taken a turn for the worse :(

    The hinge stopped rotating as well inside and split apart the corner even worse I had to remove the rear hinge cover, pop out the hinge completely and turn it with a pliers. It's back to how it was now but in splitting apart the screen it seems the digitizer has started to separate from the LCD because there's a big glue bubble in that corner now. It's not so bad since it's in the corner but it's pretty big and pressing on it doesn't seem to do anything--I think it only gets worse from here. The touch still works fine in that area but it's definitely a visual annoyance now as well.

    I've attached some pics but pretty sure the only way to properly fix this is to get a new screen assembly. Sucks they made it like this where the top lid is glued or something--they should have made a removable bezel w/screws.

    My lid and screen were in good condition too--not too many scuffs/scratches and the oleophobic coating is still intact on the screen as well. Though granted I have the stupid LCD with the image-retention issue but no telling what I'd be buying off eBay, etc. so might get the same thing again. I guess I'll have to find a screen assembly now but not sure it'll be worth it at probably $100ish USD. Guess I'll go back to the E6320 and just be careful with this one from now until I find a good cond'n screen for cheap.

    I think attempting to squeeze in glue or epoxy into there is just going to break with the pressure again anyway...I don't think there's a reliable way to fix this?

    Edit: I now see a picture of the touch lid (alone, w/o LCD) on eBay... It seems there may be be a screw insert in the bottom corners near the hinges, under the LCD.

    Edit2: Well now I'm seeing a picture of just the touch LCD, w/o the lid. Gets even more confusing because then there definitely can't be any screws. So this is really just glued together then? I dunno why my digitizer started to separate then. Very confusing as to how this is put together to begin with o_O
     

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    Last edited: Mar 10, 2019
  7. unnoticed

    unnoticed Notebook Enthusiast

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    I have had this issue on some thinkpads.
    There is no epoxy in the world that will hold up against the force that is needed to rotate the hinge.
    Its several kilos, around 7 or 8 before it starts to turn if you measure with a pair of pliers..and it has to withstand that force day in and day out.
    Convert that into torque needed to meet the specs of the adhesive in n-m/mm² it has to astronomical high and at the same time be flexible.
    And the surface area you have to work with to attach the parts is too little to gain any strength.
    Most epoxy or industrial adhesive requires at least 10x10cm for the n-m/mm² rating to be valid, gluing these small items together is too little surface area.
    You might think that its possible to solder it together with a zinc bar like any rough metal piece.
    But it might catch on fire because the metal cage in these laptops are made out of a magnesium alloy, what the exact ratio is of each ingredients you can only guess.
    If its high enough in magnesium you could heat it up so much that it catches on fire and you cannot put that fire out, you just have to let the material burn out by it self or throw sand on it to choke the reaction.
    And even if it didn't catch on fire, its harder to solder than aluminum because it oxides very fast.
    The only proper way of repairing this is to tig weld the parts together....in that rate..just buy a new assembly.

    If the parts were not damaged you could keep them together with Teroson Terostat 9220.
    https://www.henkel-adhesives.com/nl/en/product/flexible-sealants/teroson_ms_9220.html
    I used this adhesive to glue the hinges to the back panel on a T420s and it holds very well, thinkpads has moldings for the screws put into the plastic back panel, when those nuts come loose the whole assembly slices like a sandwich.

    But in your case seeing from the image, the whole cage is split and the hinge has no structure to tie back in to.
     
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  8. WindowsRevenge

    WindowsRevenge Notebook Enthusiast

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    Yeah that's what I was thinking too.

    Yeah definitely would not what a metal fire! However I don't think there's any metal here other than the hinge. The lid and LCD side are clearly plastic. There's nothing to really solder or melt the hinge just rests inside the lid and has two indents where it sits and that's about it. The LCD and lid are bonded somehow, I'm just not sure how. First I thought it was glued, then I thought it was screws but now I'm back to thinking it's glued somehow. But there's no instructions online anywhere about taking the touch LCD away from the lid, only instructions regarding the non-touch which is really straightforward to begin with.

    I don't think there is any real damage, it's just the thing is split at the corner instead of being secure. I put the hinge back in there and it's back to how it was (have to squeeze the corner together when turning to avoid the hinge from remaining stationary and causing the split. The only thing I guess is damaged now is the corner has a big glue bubble where I assume the digitiser is starting to separate from the LCD (even putting pressure on it doesn't move the bubble either so it's messed up there).

    Only thing I can really think of as a last ditch is to get some JB Weld, push it into there, clamp it together and see what happens. After that only replacement of the assembly can fix it I think.
     
  9. unnoticed

    unnoticed Notebook Enthusiast

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    Tried that, didn't hold up.
    It will crumble because there is nothing helping the epoxy to give any structure.
    If you want to try that, mix it with glass fiber or something that will give structural strength
     
  10. WindowsRevenge

    WindowsRevenge Notebook Enthusiast

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    Well I started looking at more pictures on eBay and by searching for E7250 instead of 7240 I've found a bunch more touchscreen images, separated from the lid. Looks like there's indeed some kind of tape or adhesive that bonds the screen + digitiser to the lid/hinge assembly.

    I guess I have to try to split the entire thing apart as ALLurGroceries mentioned to begin with. The odd thing is I don't get why my screen has the bubble in the corner now from the digitiser separating then, it seems like it shouldn't do that just because the screen starts to come away from the lid.

    I have to options I suppose--try to slice it apart (perhaps a razor would cut through the tape/adhesive) and then clean up the tape/glue and replace it. Or just buy a new screen...

    Will the E7250 screen fit? It seems there are a lot more touchscreens for that model than the older 7240. It looks identical but that's just looks, don't know for sure if it's the same physically and then there's the electrical connections on it.
     
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