Develop Bugs

HX4700 Hardware or Software Screen Scale?

After upgrading my IPAQ 4705 to WM6, I needed to replace the backup battery. After reassembly, the screen display isn't working correctly:
On a soft reset the first screen is correct. It's the right size and has the right size text and looks perfect in all respects. The next screen, however, shows an image that is 10 times too large for the screen. As an example, on a hard reset, it shows the correct screen, then I see the words "align screen" with the word "align" taking 3/4 of the screen and each letter being 3/4 of an inch high. The word "screen" starts on the right side and wraps around to the left side. The touch screen works, but the crosses are also large and I can't get past the align screen. I can activesync in without problem. I tried removing the welcome link to bypass alignment, but then I see the same huge text for the Today screen and all other screens.
I have carefully looked at the ribbon cable to the screen, and there is one wire that is suspect. It looks like something struck the cable right at that point. Under a microscope, the wire "looks" OK, but I can't be certain. I don't want to try to "fix" this hardware problem if it's not the problem. Since some screens display correctly, I was wondering if this could be some kind of scaling issue. Perhaps a register is storing some scale factor that would be corrected if I could align the screen, but I can't.
I would have expected the ROM reset or hard reset to fix this, but then again. maybe not.
I've tried switching ROMS, but I get the same problem with all.
Does anyone have specs for the connector or ribbon cable to the screen? I suspect that the one possibly bad wire could go to the touch screen part and the screens that look OK are ROM images (drawn without reference to the touch screen), while the bad ones are being scaled by some error in the touch screen input.
Any comments or suggestions would be greatly appreciated. Thanks!

IpaqOwner3 said:
I have carefully looked at the ribbon cable to the screen, and there is one wire that is suspect. It looks like something struck the cable right at that point.
Click to expand...
Click to collapse
I was able to trace this wire back, scrape away some of overlay to access the copper and test this wire. It was broken - no connection. It must be part of the touch screen sensing system (even though the touch screen worked). Using some SMT rework tools, flux, fine solder and very fine wire, I was able to bypass the broken single wire in the ribbon cable, and it's now working fine.

Display stay white after touch screen substitution

Hallo to all!
i've already tryied to search this topic in all the forum, but didn't find anything...pls tell me if something similar already exists!
so my problem: i have a touch pro 2 (RHOD100), and the last week i broke the touch screen (due to accidental heavy pression on it)...all works, but no TS function...
so (here starts my trouble) i decide to change by myself...i bought a new one (only TS) on ebay and make the change....
no problem with the hardware change, but now my display stay white...
some consideration:
- OS start with no problem (start sound and button sound)
- all flats are plugged correctly (checked many times)
- the backlight of the lcd works well (low light after some time)
some help? maybe i forget something important?
thanks a lot in advance to any helpers!!

db491 said:
Hallo to all!
i've already tryied to search this topic in all the forum, but didn't find anything...pls tell me if something similar already exists!
so my problem: i have a touch pro 2 (RHOD100), and the last week i broke the touch screen (due to accidental heavy pression on it)...all works, but no TS function...
so (here starts my trouble) i decide to change by myself...i bought a new one (only TS) on ebay and make the change....
no problem with the hardware change, but now my display stay white...
some consideration:
- OS start with no problem (start sound and button sound)
- all flats are plugged correctly (checked many times)
- the backlight of the lcd works well (low light after some time)
some help? maybe i forget something important?
thanks a lot in advance to any helpers!!
Click to expand...
Click to collapse
When you changed the touch screen did you remove the flex cable that connects the upper half of the phone to the motherboard? Are you sure you didn't break the LCD screen itself?

hallo,
yes i remove the flat, and plug back again where changed - when i press on the TS (with white screen) i can ear the "tap"
i cannot be sure, but it light on...i think is enought...or not?
thanks for you're help!

db491 said:
hallo,
yes i remove the flat, and plug back again where changed - when i press on the TS (with white screen) i can ear the "tap"
i cannot be sure, but it light on...i think is enought...or not?
thanks for you're help!
Click to expand...
Click to collapse
It looks like like either the flex cable got damaged or it's not plugged right. It could also be the LCD flex, where lcd plugs into the small connectors under the four buttons at the bottom of the touch screen not being connected properly. Did you lift the small levers where the flex cables go into the mother board or where the lcd/touch screen gets plugged in or did you just push them in?

i lift the lever where pull out the flex, and pull it down when restore the connection... and i'm almost sure about connection, also because them are so "stricted" in the plug himself...
but i find really strange that the lcd is on (completely white), you don't think so?
also if it is damaged, should be not white...or maybe, as you say, a flat problem?
this evening i will re-open it for a check...i don't know what else do...
maybe i will try to buy a complete kit (TS+lcd)...
i will surely let you know

db491 said:
i lift the lever where pull out the flex, and pull it down when restore the connection... and i'm almost sure about connection, also because them are so "stricted" in the plug himself...
but i find really strange that the lcd is on (completely white), you don't think so?
also if it is damaged, should be not white...or maybe, as you say, a flat problem?
this evening i will re-open it for a check...i don't know what else do...
maybe i will try to buy a complete kit (TS+lcd)...
i will surely let you know
Click to expand...
Click to collapse
The screen being white, means it's receiving power but not video signal. There coud be different reasons for that. It happened to me couple of times. What I did was lift the connector lever, pull the flex connector out (where it connects to the motherboard) just a tiny bit and secure the connector with the lever and it worked. If the flex cable is going bad it could be that just one line or two are going bad not the whole thing, thus still delivering power but not video signal.
If your problem is with the flex buying a new screen/digitizer will not fix it. When you screen is white does it go out if you slide out the keyboard?

hallo,
sorry for late answer,
i make some test with flat, but the result is the same...
the screen always stay white, but i can ear the start sound, the pression sound, etc...so it seems it's just the lcd...
maybe i can try to buy a complete set lcd+ts?
thanks for answer

db491 said:
hallo,
sorry for late answer,
i make some test with flat, but the result is the same...
the screen always stay white, but i can ear the start sound, the pression sound, etc...so it seems it's just the lcd...
maybe i can try to buy a complete set lcd+ts?
thanks for answer
Click to expand...
Click to collapse
I could be wrong, but I think it's the flex cable that is bad not the LCD screen itself. The flex cable has several small thin lines, what is happening is the power is getting to the LCD screen but the video signal is not, so most probably one of teh video signal lines is broken.

Damaged touchscreen - can the rest be salvaged?

Hi everyone.
After a sudden heavy rain, I got some water in my Gnex. I tried the old bag of rice trick, only to find out the USB port was not functioning any more, neither for PC connectivity, nor for charging.
Following the advice of a person I no longer consider my friend, I tried spraying some Isoprpyl Alcohol in the USB port. It did get it to work correctly, but it damaged the digitizer, meaning I get random touches on the lower part of the screen (where the Back, Home and Recent apps buttons are).
I took the phone to a service centre where they tried to clean it, but the issue remains. I'll go there today with my wife's phone to see if it's indeed a touchscreen issue or a motherboard issue. I'm not sure if I want to invest in a new screen (over $100 + maybe a new back cover since the current one has quite a few scratches and cracks) and I'm thinking of maybe upgrading to a Nexus 5 or Xperia Z (the latter being waterproof).
The question now would be, could I do something with the hardware? Like, root it, connect it to my wifi and use it as a web server, or connect it to my TV through an MHL adapter and get a "smart TV". Can I get it to ignore touches on the screen completely, and only accept an OTG/bluetooth mouse input?
Any idea is welcome

vladk2k said:
Hi everyone.
After a sudden heavy rain, I got some water in my Gnex. I tried the old bag of rice trick, only to find out the USB port was not functioning any more, neither for PC connectivity, nor for charging.
Following the advice of a person I no longer consider my friend, I tried spraying some Isoprpyl Alcohol in the USB port. It did get it to work correctly, but it damaged the digitizer, meaning I get random touches on the lower part of the screen (where the Back, Home and Recent apps buttons are).
I took the phone to a service centre where they tried to clean it, but the issue remains. I'll go there today with my wife's phone to see if it's indeed a touchscreen issue or a motherboard issue. I'm not sure if I want to invest in a new screen (over $100 + maybe a new back cover since the current one has quite a few scratches and cracks) and I'm thinking of maybe upgrading to a Nexus 5 or Xperia Z (the latter being waterproof).
The question now would be, could I do something with the hardware? Like, root it, connect it to my wifi and use it as a web server, or connect it to my TV through an MHL adapter and get a "smart TV". Can I get it to ignore touches on the screen completely, and only accept an OTG/bluetooth mouse input?
Any idea is welcome
Click to expand...
Click to collapse
One day I got caught in a storm having my Gnex in my pocket. Vacuum and rice tricks didn't work completely, as the phone was working properly besides recognizing the sim card (Mboard issue). What I did was buy a broken screen nexus off of Ebay, and exchanged the screens.
Now I have a fully working mobile phone, plus an MHL connected - XBMC enabled smart TV box, connected with bluetooth mouse/keyboard.
Question: Why would you need to ignore touches on the screen?

As I said, after spraying the USB port with isopropyl alcohol, it appears to have touches all over the bottom part of the screen, as if someone was constantly keeping 3-4 finger and touching away at the soft buttons. Cleaning the phone in a service centre did not help.

vladk2k said:
As I said, after spraying the USB port with isopropyl alcohol, it appears to have touches all over the bottom part of the screen, as if someone was constantly keeping 3-4 finger and touching away at the soft buttons. Cleaning the phone in a service centre did not help.
Click to expand...
Click to collapse
Sorry, I missed that info. Try searching for 'touch blocker' in Google Play. Don't know if that would work on a Gnex though.
Another (hardcore) idea would be to disconnect the screen altogether.

N7 screen went black

Yes, like it turned itself off but it did not go off as I was still getting audible email notifications. Tried everything speaking with Google support and then even Asus support who told me to go to their website and fill in an RMA form. This unit is 13 months old-out of warranty. There is nothing on the form relevant to the nexus to fill in so you cannot continue with it. So I am stuck right now and do not know what to do if anything. Any help would be appreciated.

claypoole said:
Yes, like it turned itself off but it did not go off as I was still getting audible email notifications. Tried everything speaking with Google support and then even Asus support who told me to go to their website and fill in an RMA form. This unit is 13 months old-out of warranty. There is nothing on the form relevant to the nexus to fill in so you cannot continue with it. So I am stuck right now and do not know what to do if anything. Any help would be appreciated.
Click to expand...
Click to collapse
Normally, 3 things can go wrong:
1. The cable is not connected properly. This could be caused by any impact. You take off the back cover and reseat it. It's the amber cable that runs the length of the battery. Be sure to check both ends. The one on the motherboard's end is in plain sight. The other end is hidden beneath the daughter board at the bottom of the tab, so you need to remove it to inspect the connection.
2. The backlight which illuminates the display went out. You can check this by turning the tab on and taking the tab to a dark room and shine a flashlight on the screen. If you can see the icons or the boot page, the back light is bad. The bad news is that you'd have to remove the lcd/touchscreen unit to replace the backlight. 10 times out of 10, when you do this on an original tab, you will break the touchscreen. Since it's glued to the lcd with LOCA (liquid optically clear adhesive), you will have to separate them, fix the backlight, buy a new touchscreen, then reassemble the whole thing. Most people would find it simpler to just buy a new lcd/touchscreen combo. If you're game though, I can give you an lcd back with a working backlight strip.
3. The video circuit on the motherboard went belly up. To test this, you need a micro usb to HDMI adapter like the one here , and a newer lcd TV. If nothing shows on your TV, the GPU is probably dead, in which case the only practical solution is to replace the motherboard since it's impossible to replace the GPU at home.
Good luck.

graphdarnell said:
Normally, 3 things can go wrong:
1. The cable is not connected properly. This could be caused by any impact. You take off the back cover and reseat it. It's the amber cable that runs the length of the battery. Be sure to check both ends. The one on the motherboard's end is in plain sight. The other end is hidden beneath the daughter board at the bottom of the tab, so you need to remove it to inspect the connection.
2. The backlight which illuminates the display went out. You can check this by turning the tab on and taking the tab to a dark room and shine a flashlight on the screen. If you can see the icons or the boot page, the back light is bad. The bad news is that you'd have to remove the lcd/touchscreen unit to replace the backlight. 10 times out of 10, when you do this on an original tab, you will break the touchscreen. Since it's glued to the lcd with LOCA (liquid optically clear adhesive), you will have to separate them, fix the backlight, buy a new touchscreen, then reassemble the whole thing. Most people would find it simpler to just buy a new lcd/touchscreen combo. If you're game though, I can give you an lcd back with a working backlight strip.
3. The video circuit on the motherboard went belly up. To test this, you need a micro usb to HDMI adapter like the one here , and a newer lcd TV. If nothing shows on your TV, the GPU is probably dead, in which case the only practical solution is to replace the motherboard since it's impossible to replace the GPU at home.
Good luck.
Click to expand...
Click to collapse
Did anyone else read this response and want to hit the edit button, and then type in huge letters "Time to buy a new Nexus!"

Thank you for your detailed reply. I checked the cable from the MB at both ends. Seems OK on the connections. I am unable to turn on the tab to check the backlight. That's about as far as I can go with it at this point. I am thinking that this tab is toast and to make matters worse, the abominably bad Asus customer service. I am considering replacing this with a Samsung and be done with it.

claypoole said:
Thank you for your detailed reply. I checked the cable from the MB at both ends. Seems OK on the connections. I am unable to turn on the tab to check the backlight. That's about as far as I can go with it at this point. I am thinking that this tab is toast and to make matters worse, the abominably bad Asus customer service. I am considering replacing this with a Samsung and be done with it.
Click to expand...
Click to collapse
Hey, don't lose hope! Samsung is not any better specs or quality-wise (especially the display). If you're gonna butcher the thing anyway, might as well find out. I was gonna suggest to lend you a used lcd for you to test, but I realize people for some reason are extremely wary of gratuitous offers so I won't. But if you value it, try to get a screen with a good lcd but broken digitizer on Ebay. They wouldn't cost more than 15 bucks. Once you can determine it's not the motherboard, we can go from there. I can guide you on the replacement part if you want. I'm just a hobbyist, but I have messed around with this thing enough to tell.

Graph, you are kind to offer. I also have noticed that the glass has a few cracks in it as well. At this point, I can't turn it on. It seems like when I punch the on button in there is extremely little movement if at all. So I don't know if it is still on which I don't this it is or it shut itself off. When it was black screen and on, I was getting my email notifications audibly but since yesterday-none. I am not looking to spend big bucks on these things as essentially all I do mostly is use for reading. I do want to stick with android if I replace this. I know samsung does not have as good resolution but seems to get good reviews from users.

P600 repeated Black Screen Issues -

I have a black screen issue that starts with the screen getting dim, then the next day just a black screen with sound and touch feedback.
Taking the back off and reseating the cables fixes this, but it happens every few months.
Will replacing the screen fix this issue or is there something else going on i need to address?
i'm pretty sure it's not the OS. it happened when i had TW and still happens on LOS.

Do not replace the screen
bajra79 said:
I have a black screen issue that starts with the screen getting dim, then the next day just a black screen with sound and touch feedback.
Taking the back off and reseating the cables fixes this, but it happens every few months.
Will replacing the screen fix this issue or is there something else going on i need to address?
i'm pretty sure it's not the OS. it happened when i had TW and still happens on LOS.
Click to expand...
Click to collapse
Don't replace the screen the problem is the ribbon cables. The best solution is to reseat the cables then place a layer of electrical tape to secure the ribbon cables so they do not move when you drop the tablet (accidentally or just setting it down on a surface).
Mike

Maybe you have an idea about this? Very perplexing. My screen started getting darker in one corner. then it blacked out. I had already read about reseating the ribbon cable, but the really weird thing is on a reboot the screen comes back on. It has done this several times. Last time, I thought it had blacked out for good, but nope, it is still coming back on after a reboot. This has happened after several ROM updates. I am at a loss.

Same Problem
C0BRA01 said:
Maybe you have an idea about this? Very perplexing. My screen started getting darker in one corner. then it blacked out. I had already read about reseating the ribbon cable, but the really weird thing is on a reboot the screen comes back on. It has done this several times. Last time, I thought it had blacked out for good, but nope, it is still coming back on after a reboot. This has happened after several ROM updates. I am at a loss.
Click to expand...
Click to collapse
The root cause of the fading in one corner is the same problem...badly seated ribbon cables. My Note 2014 experienced a faded corner too before the backlight stopped turning on when I woke it up from sleep mode. Fix action was the same...remove the black plastic cover, flip it over and carefully remove and replace the ribbon cables to the display. To prevent future problems carefully use a sticky black electrical tape to help hold the ribbon cables in place. Check the function (push the power button to put the tablet tot sleep then wake it up) before you replace the cover. Good luck!
- Mike

Pictures
Mike_SattyEng said:
The root cause of the fading in one corner is the same problem...badly seated ribbon cables. My Note 2014 experienced a faded corner too before the backlight stopped turning on when I woke it up from sleep mode. Fix action was the same...remove the black plastic cover, flip it over and carefully remove and replace the ribbon cables to the display. To prevent future problems carefully use a sticky black electrical tape to help hold the ribbon cables in place. Check the function (push the power button to put the tablet tot sleep then wake it up) before you replace the cover. Good luck!
- Mike
Click to expand...
Click to collapse
For those that are interested...here are so pics of the ribbon cable reseating process. I had to do this again to my P600 after a hard drop to a wood floor to nights ago and found the back lighting not working correctly.
Symptoms: 1. Darker spot in corner of display on wake up from suspend. 2. Pressing power button to wake up after tablet put its self to sleep after the screen timed out (turned off display) resulted in lighting of only the soft return and menu buttons and the display back light failed to turn on resulting in a black screen.
The fix action:
1. Turn tablet off and remove the pen from its built in holder.
2. With screen facing up, use a plastic key card (hotel room key or reward card) to go all the way around plastic-chrome border of the tablet and unlock the back cover from the display.
3. Flip the tablet over and lay it on a soft cloth. Carefully flip up the black locking tabs of the ribbon cables (these things are delicate and are easily broken unless you use minimal force). Only the cable on the left can be completely removed (see the first pic). The lower end of the right cable is attached to the display. Fold it out of the way. Remove the cables and inspect ends for damage or debris. reseat the cable paying attention to the tiny locking tabs of the cables, then lock them back into place.
4. Pick up the tablet. With the screen facing you rotate it until the USB port is facing to your left. On the upper right side of the table you see three round silverish dots. These are membrane switches. Press the upper switch carefully with your finger nail (you fill the switch move and make contact). If the screen turns on, carefully flip it over and lay the screen on a soft cloth. Carefully put electrical tape on ribbon cable to hold it in place (see pic 2).
5. Flip over the tablet over and press the power button again to turn on the tablet and verify function.
6. Replace the cover of the tablet. Go around the entire tablet edge and gently press the screen into the cover. You should hear the locking tabs snap as they lock back into place.
Recovery if the screen does not light after replacing the ribbon cables.
1. Unlock and remove the ribbon cables again.
2. Remove the five screws holding the battery in place.
3. Carefully lift the battery out of its position and gently lift up on the wires connecting it to the tablet, the connector lifts up from the tablet to separate.
4. Wait 30 seconds and replace the battery and cables. Repeat step 5 and 6 above.:good::good::good:
- Mike

as mike suggest, unless hardware issue, reseating cable fixed my similar issue as well.
make sure to secure those cables with the tape so it doesn't happen again.

This! As Mike recommends above! I replaced a failing battery and the unit worked great, but coincidentally dropped my note the next day. The screen was black and I figured it was dead until I read this, figured nothing to lose and opened it back up. I reset the ribbons, taped them down and I'm back in bussiness. I suppose the drop was just enough to lose or unseat the ribbons. I taped thenm in place and all is good. A million thanks!