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How to Figure out if touchscreen or LCD or both are broken?

Hello Friends,
yesterday when i saw the screen of my xda exec i saw a big black spot on the centre of the screen, not sure how it happened. i can still make calls from the phone.
but now i want to figure out whether i'll need to replace touchscreen or the LCD or both but i dont know how to figure out which one is broken.
Any help will be really appreciated on this.
Ashwani

Chances are
if the touch capability is intact, it's your LCD. The opposite, where the screen looks fine, but the touch is gone, would be your digitizer. However, unless you know how to replace a digitizer, I recommend getting both, LCD and a digitizer in one unit, rather than attempt to assemble the screen yourself. Which, judging by your question, is likely to be the case.

enigma1nz said:
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I would only iterate what enigma1nz had to say . It's at least your LCD at fault, but buy both as one unit. Or, buy a Uni that guarantees a working LCD+Touch pad (ie, a Uni with only a broken broken mobo/usb/doesn't boot etc) from eBay or the like.
First of all, I would just take the screen part of the Uni apart and check all is tight when replacing, as if the LCD has no obvious cracks, it's very likely a rubber-strip contact or similar.
NB. If anyone is interested in purchasing a fully-working Uni (brand new casing), with a non-functional touch/digitizer (guaranteed working everything else incl. LCD), I'm about to put on eBay. (PM me)

Chances that an LCD + digitizer will fix this?

A coworker I started working with a few months ago told me about the much-better Sensation he had before his MyTouch 3G. It seems that he still had it, but stopped using it "because the screen cracked." I correctly surmised that it was a simple and cheap to replace touch screen digitizer and described to him that it was "just the glass cover" and that it was "cheap to replace." I have done many such repairs on other phones and gadgets.
He then told me that he had continued to use it until the LCD went blank. There is no reason to think that the LCD inside suddenly cracked, but I can only assume that it also sustained some kind of damage and now also requires replacement. Knowing that the LCD isn't cracked, what are the chances that a replacement LCD + digitizer will restore the phone? I'm concerned because we've already purchased a kit for $65.

Nobody can tell you that off the internet. If we do, that would be pure guess, just as accurate as you would have guessed.

sawo said:
Nobody can tell you that off the internet. If we do, that would be pure guess, just as accurate as you would have guessed.
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Well, someone could have had the exact same problem and already tried it. I ran into people with the same problem already. I'm just looking for more because some, no doubt, have tried it and others may have an alternate explanation. Reasonable.

there is a good chance that will fix the problem. but since the LCD was working for a while until it blank out, it is possible the problem might be with the circuit board. only way to know is to try it out.

CZroe said:
Well, someone could have had the exact same problem and already tried it. I ran into people with the same problem already. I'm just looking for more because some, no doubt, have tried it and others may have an alternate explanation. Reasonable.
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The LCD could go blank for several reasons. Faulty LCD, loose cable, faulty board etc. etc. Even if someone had the same problem, the reason for it could be completely different, thefore this wont help you at all except for giving you hope. If this is what you need, then i would say "yes, the change of lcd & digitizer should fix the problem" but you never can be sure unless you try When you start the phone, do you hear the startup sound? This could at least indicate that the phone isnt completely faulty.

brabusamg55 said:
there is a good chance that will fix the problem. but since the LCD was working for a while until it blank out, it is possible the problem might be with the circuit board. only way to know is to try it out.
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The plus side is that you can't make it worse. So you've got nothing to lose by trying to repair it, other than the few bucks for the parts.

Well, I took it apart to re-seat all the cables and it's still blank. Reading online, I see that a lot of dropped Sensations/Pyramids develop a loose/broken SMT capacitor component near the headphone jack, but I'm not registered on any of the forums I see it discussed on and I can't see the pics. They describe a slightly different problem anyway (screen goes blank after standby). I needed sleep, so I put it all back together and I'll check that out when the parts get here. My hunch is that the LCD panel is fine and that I'll have an extra, assuming the capacitor problem is fixable. I've done some delicate soldering work before but I can't really say that I'm good at it! I didn't see any loose SMT components rattling around so I hope it didn't fall completely out somewhere.
Skipjacks said:
The plus side is that you can't make it worse. So you've got nothing to lose by trying to repair it, other than the few bucks for the parts.
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Thanks but it's almost $70 for the parts.

Works great! Well, it had the touchscreen sensitivity issue pretty badly but the T-Mobile OTA update fixed that. Transferring all the adhesive bits from one screen to another was down-right frustrating, but I pulled it off and I only see a single spec of dust inside. The dude will be thrilled. I broke the earhook on my Looxcie so I did not make a video but it was full of me tearing and ripping the things anyway and not a good example of how it should be done!
FWIW, there was no way to remove the old screen without denting up the backing plate and prying the heck out of it to free it from multiple adhesives and glues, so I would not have had two good LCDs after testing the replacement even if there was nothing wrong with the original. Good thing it was the LCD at fault! I didn't have to drill anything like the glass replacement video I watched instructed me to do. They didn't realize that the LCD removal allows the flex PCB through just fine. I forgot to thread it back through before seating the replacement LCD in the adhesives and tape left-overs but it flexed enough to allow it through without removing, which was quite a relief after seeing how the original fared after being removed.

[Q] Touchscreen not working, digitizer probably not the issue, what else could it be?

I dropped my phone a few weeks ago, and the touchscreen stopped responding to touches in approximately the top third of the screen. If I run Screen Touch Test on the phone and I scribble all over the screen, my scribbles don't show in the top third of the screen, except where they are bunched together in in three straight lines. Being a noob on xda, I can't post an actual link to an image of this failure, but you can find one at imgur.com/DenQepu&Jj7dq5g
It looked like it was caused by a broken digitizer so I replaced it, but this didn't fix the problem. The second image in the above URL shows the phone in the same test with the new digitizer. It basically looks the same as the first image, though.
The digitizer vendor shipped me a digitizer which simply didn't work at all, the first time through, so it is possible that they shipped me a digitizer with the exact same issue as the original one. How common is this failure mode? And if it's likely that the new digitizer is fully functional, is there anything else I might have broken by dropping the phone which could be causing this failure? Having torn down and reassembled the phone quite a few times now, I can't imagine what else it could be...

The first thing you should do is check out THIS THREAD. Also I've had Bad Digitizers sent to me from shady vendors. So I would suggest going with a reputable vendor.

Thanks, prboy. I read through the thread, and it suggests it could be a problem with the ribbon cable. It had occurred to me that the problem might be with the cabling, so I have been looking at it pretty carefully. I don't notice anything obviously wrong with it. No tears, and the cable junctions seem to be working nicely, as best my naked eye can tell. :cyclops: No crunching sound when I open the keyboard. All cables were securely affixed to solid components when I first opened the phone, so it's also hard to see how dropping it could have damaged the cable.
All that said, I am a complete noob at this. This is the first time I've attempted such an intricate project. So I welcome critical feedback. Does a cable failure seem more likely at this point, given the touchscreen identical failure with the two different digitizers? Or does identical failure in the digitizers seem more likely?

It's hard to tell given that I don't have the Device in front of me. But that being said. As long as the Digitizer Vendor is reputable. I'd say that the Cable failure is a definite possibility. It would not be unheard of having a Flex Cable failure, even though it looks good. I've had them be bad, and still look good. Were you 100% sure the Digitizers were bad ? Make sure You and the Work surface are grounded. Also wear Latex No Powder Gloves. You will be very happy you did.

Thanks again, prboy. Found an otherwise functional evo 4g shift with a cracked screen on ebay for $25, so I will swap in my screen/new digitzer onto it, and see what happens. If all is well, it was definitely the digitizer which broke. Otherwise, I've got yet another digitizer to return to the vendor, and they will be getting very bad feedback from me. Will let you know how it goes. (After it arrives some time next week.)

Ok kool. Keep us posted
TEAM MiK
MikROMs Since 3/13/11

HTC Sensation death after Digitizer replacement

Hello,
Touch screen glass was broken, due to my phone fallen on the ground. The LCD was still working perfectly so i've ordered a new genuine digitizer for my HTC Z710E.
After replacing it my GSM does nothing . When charging i see the charging light lighting up in red or either green when full, but besides that i won't do anything. I disassemblied the phone again twice, reconnect all the connectors and still nothing. Sometimes my phone vibrates and sometimes when i push the power button the charging light disappears but that are the only signs of living.
Is this a common failure after replacing the digitizer? Did i overlook something?
Hopefully you guys can help me out.
Thanks in advance!

If the LCD ribbon cable is, in fact, getting a good connection then I would probably lean towards the lcd itself having been damaged during the install. Due to the construction of the sensation, it can be difficult removing the lcd without damaging it even for an experienced tech like myself.
What I would suggest would be to go ahead and order a new lcd. This would also be a good time to double check that the part number on the new digitizer's ribbon cable matches that of the broken digitizer you removed, as the incorrect part will lag when the screen is turned on at best and will not work at all at worst. As far as I know, the sensation and kindle fire are the only devices like this where you will have slightly different parts even within the same model and region.

Duck Norris said:
If the LCD ribbon cable is, in fact, getting a good connection then I would probably lean towards the lcd itself having been damaged during the install. Due to the construction of the sensation, it can be difficult removing the lcd without damaging it even for an experienced tech like myself.
What I would suggest would be to go ahead and order a new lcd. This would also be a good time to double check that the part number on the new digitizer's ribbon cable matches that of the broken digitizer you removed, as the incorrect part will lag when the screen is turned on at best and will not work at all at worst. As far as I know, the sensation and kindle fire are the only devices like this where you will have slightly different parts even within the same model and region.
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Hmm i already thought so . I did it really really careful, but despite that it broke.
Time for getting another phone. Don't have much money now, but i shall see what's for sale

[Q] Replacement screen, touch unresponsive.

Hi, I dropped my phone a few days ago and completely smashed the screen. It was still usable for a day or two, but the cracks gots worse and I started to get random touches registered to the point where the phone became unusable. So I went to eBay and purchased a replacement screen assembly including the frame. It arrived today and I have just fitted it, phone boots up perfectly and the picture looks great, but the touch is completely unresponsive.
Have I just been incredibly unlucky and received a dud screen? Is there anything I should do to test it out and make sure there is nothing wrong with the components I have before I contact the seller?

Perhaps you sould review this youtube..... It's excellent.........
I have replaced a few Nexus 5 LCD and digitizer with frame with success
I hop this helps Let us know how you do

Blacksmith5 said:
Perhaps you sould review this youtube..... It's excellent.........
I have replaced a few Nexus 5 LCD and digitizer with frame with success
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Your link didn't show for the youtube - could you write it out or give some search keywords? I broke my glass and need to decide to fix it or buy a different phone. I've read the other broken screen threads and some of the complaints are the aftermarket stuff aren't OEM and therefore not the best quality or long lasting. Could you say where you bought your LCD and digitizer with frame? thanks, JD

hunky-d said:
Your link didn't show for the youtube - could you write it out or give some search keywords? I broke my glass and need to decide to fix it or buy a different phone. I've read the other broken screen threads and some of the complaints are the aftermarket stuff aren't OEM and therefore not the best quality or long lasting. Could you say where you bought your LCD and digitizer with frame? thanks, JD
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Click to collapse
There are no LG OEM parts from aftermarket. Some vendors claim their product was produced in the same factory as the LG parts and therefore are OEM but there is no way to prove this and it is more than likely a lie. Look for a description with something like Grade A or Grade AA. If there is no mention of grade it is likely B stock.
You can try cleaning the connector with alcohol and reseating. If it doesn't you received a dud, it happens even from a reputable seller. On my second replacement I got one that doesn't always calibrate correctly when the screen is awakened.

hunky-d said:
Your link didn't show for the youtube - could you write it out or give some search keywords? I broke my glass and need to decide to fix it or buy a different phone. I've read the other broken screen threads and some of the complaints are the aftermarket stuff aren't OEM and therefore not the best quality or long lasting. Could you say where you bought your LCD and digitizer with frame? thanks, JD
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Sorry about that Here is the link. It is very wel lexplained and easy to follow plus the photography is excellent.
I hope it helps you out
www.youtube.com/watch?v=OPuCmfhzgbg
M