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Screen is blank but touch screen works ***HELP***

I recently got a touch pro of a friend with a damaged screen that didn't turn on but the touch screen was responsive. Apparently he sat on it and the screen broke.
I then acquired it and replaced the LCD screen and i turned it on but all it shows is a blank black screen with the backlight on. I was tapping while it booted up and it was making that beep noise so i know the touch screen works. What do i do now.

dazz245 said:
I recently got a touch pro of a friend with a damaged screen that didn't turn on but the touch screen was responsive. Apparently he sat on it and the screen broke.
I then acquired it and replaced the screen (with digitalizer) and i turned it on but all it shows is a blank black screen. I was tapping while it booted up and it was making that beep noise so i know the touch screen works. What do i do now.
Click to expand...
Click to collapse
if the lcd is damaged and you only replaced the digitizer then that wont solve the problem, the digitizer just sits ontop of the lcd and recognizes your touches, hence why it mite know that your touching the screen but the screen is still blank

mancsoulja said:
if the lcd is damaged and you only replaced the digitizer then that wont solve the problem, the digitizer just sits ontop of the lcd and recognizes your touches, hence why it mite know that your touching the screen but the screen is still blank
Click to expand...
Click to collapse
I replaced the LCD along with the digitalizer. Tats what i meant.

Sounds like either the new screen is inop on fit (fraid you need another to test, then send the first back as faulty), or the fault is not the LCD itself.
Possibily its the wrong screen, or its not installed correctly, or you damaged either the screen or the controller when installing.
I'm afraid you dont have many options - take it apart & rebuild to ensure correct parts & fitment, spend £££ on alternative parts to see whats broken (or serious £££ on test equipment!), send it off for repair or give up!
I'd go for option 1 first
If your friend sat on it hard enough to break the screen, i'd be looking for any damage / cracking to the boards / ribon cable mounts and be looking very carefully at the mountings of any IC chips. Incedently, when (s)he sat on it, did the screen work at all? and was it 100% working before they did?

Okay thanks for the replies. I just bought a flex cable where the slider thing is because the old one looked a bit old and flexed out and on inspection of the old screen i found a tiny rip on the screen's flex cable too. I wait for my cable and see if it works and if it doesn't then i'll sent the screen back as faulty and get a new one and if that doesn't work then I'll give up and sell it again

hi
sorry to wake up an old thread.
so what's your solution/conclusion?
is it the flex, or the LCD that broke?
i have the same problem right now.
thanks

was mainboard

FUZE keypad backlight and LCD backlight problem. Please help...

New Problem :
Please see post #10.
Old Problem ( solved ) :
Hello,
I had told my problem in this thread but got no response so had to create a new thread to see if someone helps.
My problem ( I mean my fuze's ) is :
Firstly my fuze was having few scratches and the digitizer was broken lil in the edge/corner so I thought to replace its digitizer.
Brought new digitizer ( 2 months back ), disassembled the device and while removing the flex cable, broked its buttons strip ( volume and ptt button ) and while removing/separating lcd from digitizer, I destroyed both!
So next I brought new lcd and flex cable. Stupid seller sent touch pro flex cable instead of fuze. Had it return it and the fuze flex cable is on way now.
In the meanwhile, I tried to install new lcd+digitizer and damaged flex cable but I'm getting only backlight and no display/image. Sometimes I get thin RGB/rainbow vertical lines and once or twice I got the display/image too. As the adhesive conductive tapes/fabric/stickers got weaker I brought new copper conductive tape ( Like this ) and sticked them but still I'm not getting display/image and only backlight.
I'm very fedup and stressed about this although spent 100$ and Due to this, I able to cook roms and I'm out of xda dev since 2 - 3 months :'(
If someone could help, you will be greatly appreciated. Please please help!
I don't have money to buy new device either and have no mobile phones to play with since from fuze is dead.
Thanks a lot in advance....
Best Regards

I replaced the lcd in my phone and had the same problem. I later discovered that I didn't have the ribbon connector in all the way. I hope this helps.

you need a working flex cable...the same thing happened with but on a nokia n95...the blacklight was comin but no display changing the flex helped

Cingularman said:
I replaced the lcd in my phone and had the same problem. I later discovered that I didn't have the ribbon connector in all the way. I hope this helps.
Click to expand...
Click to collapse
I'm not a mobile tech.., could you please let me know what/which is a ribbon connector?
Thanks for the help though.
djteotancolis said:
you need a working flex cable...the same thing happened with but on a nokia n95...the blacklight was comin but no display changing the flex helped
Click to expand...
Click to collapse
But had it working once and twice. However, I will get new flex cable in few days.
BTW; I had also tried the new touch pro flex cable and had same issue.
Thanks for the help though.
Best Regards

CRACING said:
I'm getting only backlight and no display/image
Click to expand...
Click to collapse
Hi
I had the same problem last night (wasted 3 hours). Just replaced my LCD as well, broke digitizer was a problem. Anyway, after taking a phone a part 3 time figure out what the problem was.. The two ribbon cables have to touch (mostly likely a ground).. The LCD one and log flex one.. I will try to find you a picture..
Now I have a different problem, can't align the screen properly. The right side on screen is way off.. What a mess..

Green

sadik007 said:
Hi
I had the same problem last night (wasted 3 hours). Just replaced my LCD as well, broke digitizer was a problem. Anyway, after taking a phone a part 3 time figure out what the problem was.. The two ribbon cables have to touch (mostly likely a ground).. The LCD one and log flex one.. I will try to find you a picture..
Now I have a different problem, can't align the screen properly. The right side on screen is way off.. What a mess..
Click to expand...
Click to collapse
sadik007 said:
Green
Click to expand...
Click to collapse
I tried everything but didn't got it working. Though I have doubt on original flex cable that I broken while removing.
I have trouble with getting new flex cable on ebay. First the seller sent wrong flex cable ( TP's which it doesn't fit for fuze ), 2nd time the flex cable lost in shipment and 3rd the seller didn't had stock to resend so refunded.
Now I have brought the flex cable from different seller and its about 14 days and not yet received.
When I tried touch pro flex cable I didn't get the display but only backlight but once or twice I saw the display so I think it was something wrong in my connect. However I didn't had much time to test the device using touch pro flex cable because I had to return it!
This is what I'm playing with my device since 4+ months. Mostly waiting waiting waiting......
Thanks...
Best Regards

I can see that ribbon hold contact.

obaz said:
I can see that ribbon hold contact.
Click to expand...
Click to collapse
The ribbon aka conductive tape/sticker I have is no longer usable. Its adhesive gum is too weak and no longer sticks. I have searched lot to find such conductive tape/sticker and found copper conductive tape/sticker. Using it now.
@sadik007 and all
I got the flex cable today and after testing, I' getting same problem. No display but only backlight. I see some minor rainbow lines which haven't saw before but as said, I checked the grounding and everything seems correct.
Fed up of this and desired to sell it as parts or repairable...
Best Regards

Finally my fuze is back alive.
Got Correct Flex cable and new LCD. Now its working perfectly.
However, a minor problem if anyone can help.
The brightness setting of LCD in settings -> System -> Power -> Backlight seems to work only till 40% and then after it doesn't increase the brightness of the lcd.
In auto mode, its same. I think the brightness is working only upto 40% and then it doesn't increase.
Cannot understand whats but I guess its because the seller gave me diamond lcd instead of touch pro/fuze. As I can see, diamond lcd doesn't have variable resistor and my friend say its a brightness setting.
But the hardware setting should be atleast full and we could decrease through software.
Can body help me how to solve this problem? I guess its not possible.
P.s the brightness from 0% to 40% is not bad to use but may have trouble in sunlight.
Thanks a lot for all your helps...
Best Regards
p.s My problem is something like this but the backlight is working fine.
Edit;
I don't think my FUZE stops giving troubles. New problem started since last night and today.
As the backlight was lil dim on sun light, I went to try Lumos app. Didn't saw any difference, just sucked at 40%
Today when I booted my fuze morning, it started to do some malfunction in LED lights ( LCD backlight and front penal keypad backlight light ). Backlight of keypad is no longer working when pressed its button but buttons work fine. And also if I slide out the hw keyboard, the home button backlight turns ON. and also the d pad circular light and back button backlight.
Cannot under stand what the hell is going on. If I get any SMS or EMail, d pad circular light rounds fine but if I connect USB to charge, d pad circular light doesn't work.
I removed the Lumos app, softrebooted, hardrebooted, and reflashed but still same problem.
Any idea?
I guess I'm stupid or the device is fooling me.
Thanks again...
Best Regards

Bump...
I don't think my FUZE stops giving troubles. New problem started since last night and today.
As the backlight was lil dim on sun light, I went to try Lumos app. Didn't saw any difference, just sucked at 40%
Today when I booted my fuze morning, it started to do some malfunction in LED lights ( LCD backlight and front penal keypad backlight light ). Backlight of keypad is no longer working when pressed its button but buttons work fine. And also if I slide out the hw keyboard, the home button backlight turns ON. and also the d pad circular light and back button backlight.
Cannot under stand what the hell is going on. If I get any SMS or EMail, d pad circular light rounds fine but if I connect USB to charge, d pad circular light doesn't work.
I removed the Lumos app, softrebooted, hardrebooted, and reflashed but still same problem.
Any idea?
I guess I'm stupid or the device is fooling me.
Thanks again...
Click to expand...
Click to collapse

Same problem.
Backlight setting changes only 1-4 interval and does not brighten 5 and more.
I had heard that problem one sells his tp which's lcd replaced.
Options:
1) while replacing, flex can be damaged. I do change screens for 6 years and hard to beleive it.
2) keypad membrance can be damaged while replacemnt of lcd. More harder than option 1.
3) eBay sellers sells fake lcd screen.
I handle over 5 diamond and tp screen far away and still keep some cracked ones. They all different from each other. Somehow there must be different versions of these lcd's.

By the way I also tried a diaond lcd and it gives same error.
first 4 step is ok but no more 5 to 10 steps working.

Problem was solved:
HTC P3700 LCD and P4600-T7272-touch Pro LCD screens are different.
here is the differences illustrated on photos:

@sokomind
nice find. Yeah I do see the changes from touch pro lcd and diamond lcd. touch pro lcd has 10 led levels and diamond has only 5.
Part No :
Diamond LCD with 5 LED brightness levels : 60H00130-00M
Touch Pro LCD with 10 LED brightness levels : 60H00129-00M
29 is what we need for Touch Pro but in ebay sellers don't know the difference of these lcds. They ship what ever stock they have. I had requested to send Touch Pro LCD and also said the part no but they sent the diamond LCD.
Damaged 3 times in shipping and when I got the working one, it was diamond lcd.
Anyways, now I'm using the device has a 3g data card and 3g router. Working g8.
Thanks...
Best Regards

I still have the problem as #"10 cracing.
I got a diamond lcd and then ordered a touch pro lcd.
Yes TP LCD is brighter but it is still working 4/10 on brightness. And then I see that my flex cable has lost one of the way. I try to fix it but it still give me 4/10. I do not know if it fixs a new flex. I do not want to spend $20 more.
Have you spare TP flex not fuze?

[Q] Sensation dried, backlight not working

So my Sensation had water poured on it and it didn't work.
I managed to dry it out and now everything is working, except the backlight. In a brightly lit room, I can roughly see the display, and can make sure that touch and vibration is working, but the backlight doesn't switch on, so the screen is barely visible.
In a dark room, I can see that the capacitive buttons backlight works perfectly, and is still quite bright. So the only thing I can see in a dark room is a white light from the bottom of the phone, and nothing on the screen.
Also, charging works. Booting into bootloader works, but of course the backlight doesn't work too. I had to look into it in a lit room at a certain angle to see it
So now the question is: What is are the possible problems, and is there a possible fix?
Is there a chance of a loose wire, or is the backlight spoiled and require a replacement?

KaiJun said:
So my Sensation had water poured on it and it didn't work.
I managed to dry it out and now everything is working, except the backlight. In a brightly lit room, I can roughly see the display, and can make sure that touch and vibration is working, but the backlight doesn't switch on, so the screen is barely visible.
In a dark room, I can see that the capacitive buttons backlight works perfectly, and is still quite bright. So the only thing I can see in a dark room is a white light from the bottom of the phone, and nothing on the screen.
Also, charging works. Booting into bootloader works, but of course the backlight doesn't work too. I had to look into it in a lit room at a certain angle to see it
So now the question is: What is are the possible problems, and is there a possible fix?
Is there a chance of a loose wire, or is the backlight spoiled and require a replacement?
Click to expand...
Click to collapse
It's hardware related, and yes, it's fixable. AFAIK the baclight is a part of the display itself, so a replacement might be required. However this could also result from bad contacts. you can try replugging your display (there is a guide of the procedure on iFixIt). And the problem might be in the socket itself (in the motherboard).
You are quite lucky to have your device almost fully functional. I suggest trying the second method (trying to reconnect the display to the board) before buying a new display, is it might solve it.
Good luck.

astar26 said:
It's hardware related, and yes, it's fixable. AFAIK the baclight is a part of the display itself, so a replacement might be required. However this could also result from bad contacts. you can try replugging your display (there is a guide of the procedure on iFixIt). And the problem might be in the socket itself (in the motherboard).
You are quite lucky to have your device almost fully functional. I suggest trying the second method (trying to reconnect the display to the board) before buying a new display, is it might solve it.
Good luck.
Click to expand...
Click to collapse
I can't really find the guide. Can you please post a link to it?
Thanks

KaiJun said:
I can't really find the guide. Can you please post a link to it?
Thanks
Click to expand...
Click to collapse
Here:
http://www.ifixit.com/Guide/Touchscreen-Digitzer+Replacement/8924/1
It's a guide for repairing a broken screen. but it explains how to open the device and replace it, so it's good.
Just remember to follow it step by step, as pulling the wrong component might cause permanent damage to your device.
Good luck

astar26 said:
Here:
http://www.ifixit.com/Guide/Touchscreen-Digitzer+Replacement/8924/1
It's a guide for repairing a broken screen. but it explains how to open the device and replace it, so it's good.
Just remember to follow it step by step, as pulling the wrong component might cause permanent damage to your device.
Good luck
Click to expand...
Click to collapse
All my contacts are good...
Seems like it need a screen replacements then.
Thanks alot anyways!

Black screen (but backlight ok) after screen replacement

Hello
I just replaced a broken screen on my moto g (broken glass, but display+touch was OK).
Once reassembled, the screen remains black, but the backlight is working and the phone is booting (I can even see its content via usb).
I also tested with old broken screen but it's the same.
I even found a thir lcd to test, and same result.
Does anybody already experienced same thing (I think yes, because I saw such comments in disassembling videos).
Does it mean I damaged something on the mainboard ??? what could it be ?
Thank you for your help

Hi, did you ever fixed this problem? I'm experiencing exactly the same.
Thanks,
s
denseye said:
Hello
I just replaced a broken screen on my moto g (broken glass, but display+touch was OK).
Once reassembled, the screen remains black, but the backlight is working and the phone is booting (I can even see its content via usb).
I also tested with old broken screen but it's the same.
I even found a thir lcd to test, and same result.
Does anybody already experienced same thing (I think yes, because I saw such comments in disassembling videos).
Does it mean I damaged something on the mainboard ??? what could it be ?
Thank you for your help
Click to expand...
Click to collapse

Yes, same problem here. Anyone have any ideas ?

i had the same problem with my moto g and the problem was the screen brightness was turned right down, so best thing to do is try goto top of screen with your finger and try scroll down and swipe across where the brightness bar is, (if you get what i mean lol)

MTCD screen is displayed mirrored

I am facing a very strange bug since yesterday on my MTCD KGL.
The screen is mirrored, but the touch panel is not. So everything looks like seeing it through a mirror, but the touch panel is still in the correct orientation.
So e.g. a "Cancel" button is displayed as "lecnaC" and is on the right, but I still have to touch on the left to push it.
Even the boot logo and the recovery are mirrored.
WTF???
Do you have an idea what is going on with my unit?

Damn, this thing is not really usable anymore.
Just another "cheap" China product for the bin.
I should have better lit some cigars with the three 100€s...

So out of nothing it mirrord en before not?
Then it's software problem so fixable... flash MCU, flash image.
Everything comes form China nowadays, besides you know the risk if you want to buy cheap unit...

dude-nl said:
So out of nothing it mirrord en before not?
Then it's software problem so fixable... flash MCU, flash image.
Everything comes form China nowadays, besides you know the risk if you want to buy cheap unit...
Click to expand...
Click to collapse
Yeah, did that already. Didn't help. That's why I'm like wtf...
Meanwhile I found out, that when I'm playing with the hardware power button, pressing it until reboot, that's flashing three times, then randomly pressing it short or long, I can change the mirroring from "flip over short side" to "flip over long side". But that's even worse. Did not manage to get it to correct orientation.
I know sometimes you win, but this time I seem to lose heavily.
Thanks pal.

This happened to mine and i couldn't understand what happened...tried every setting and a factory reset with no luck. And then one day it fixed itself. HOWEVER i did read on another forum a display cable comes loose inside and causes this. Just need to open it up and re secure the display cable...

This happened to my mtcb joying unit. I asked the manufacturer and they said it's like the graphics chip.
Sent from my iPhone using Tapatalk

Normally these use a long ribbon cable to connect the internal boards together and then another to connect the display board to the LCD.
On my last unit the LCD cable was pinched by the metal case, causing random display issues.
Taking it apart and readjusting the cable so it was not pinched solved the problems.
Most manufacturers put the ribbon right at the bottom of the case, so any pressure on the bottom of the LCD can cause issues.

zoppa said:
I am facing a very strange bug since yesterday on my MTCD KGL.
The screen is mirrored, but the touch panel is not. So everything looks like seeing it through a mirror, but the touch panel is still in the correct orientation.
So e.g. a "Cancel" button is displayed as "lecnaC" and is on the right, but I still have to touch on the left to push it.
Even the boot logo and the recovery are mirrored.
WTF???
Do you have an idea what is going on with my unit?
Click to expand...
Click to collapse
Hi there. Did you solved the problem? I have the same issue. What is the fix for this problem?

Sorry bro,
I have no solution.
It disappeared after a few week.
Sorry.