On a black background is a white dot, but on a white background it is not visible.
Dead pixel?
Yep. That's what is usually called a "stuck pixel", in opposition to dead pixels which are always black.
it means that it is possible to fix it?
AFAIK, no, it's not possible. But pixels on the HD2 are small, you will probably get used to this. I have a stuck subpixel (not a full pixel, when the screen is all black I have a green dot), and I am unable to notice it unless I look for it very carefully. Forget it and your eyes won't be meeting it more than once a month.
Hey guys check this post out, I think you both might want to read this, very smart guy member facdemol.
http://forum.xda-developers.com/showpost.php?p=12670084&postcount=18
thanks for quoting T-Macgnolia.
yep, as i explained on those 2 posts in that topic one single pixel on hd2 screen's working with something like theese
- 3 subpixels
- each subpixels is made up of a pair of liquid crystal and driving transistor
- each transistor is linked to a processing chip (it organizes the screen into columns and rows, and drive them separately)
- each processing chip (the ones that trigger columns and the ones that trigger lines) are linked to a lvds bridge (that's some sort of protocol used to communicate to the gpu's analog output).
- gpu or other video processing subsystem
How to recognize various hardware failures occuring to the screen:
- white screen (nothing displayed) - this is pretty serious. As i've posted on my other topic, the crystals in the screen are normally transparent. If you apply various electric signals the matrix will actually produce colors by blocking various light wavelengths. If you get a white screen and you have already determined somehow it's not related to software issues, this most probably means faulty lvds bridge or connector (the display connector). Because the lvds is not communicating with column and row processing crystals - nothing is displayed on the screen. Entire matrix is powered off. Another cause can be a faulty GPU or video subsystem. If no video signal is being sent, the matrix will be also powered down. With crystal in their natural state, they will be transparent, thus - white light. Not user fixable, each part must be diagnosed, special equipment required.
- screen working but color lines appearing on the display or permanently there. You may have seen a laptop or tv doing this. The display works but there are some strange lines that are permanently there and either don't change color, or change it in a strange way. This happens when you have a faulty row or column driver. If that chip fails - all mosfet transistors that drive pixels in that region of the display will either stop working or work in an erratic way. Thus you get... a line (vertical or horizontal) on the display. Not user fixable, in 80% cases it requires another display as the faulty chip is in most cases embeded into the display module itself.
- screen works but with strange colors (inverted, red-ish, blue-ish or whatever). The lvds bridge - that feeds video signal to the processing chips on the display, contains a small subsystem called contrast & crominance setting. It's fixed on most displays (although i found some older pda's where this can be fine tuned). Simply put it's a small circuit made up of a negative voltage driving a PNP junction bipolar transistor working in a voltage divider circuit. The divider will actually... well.. divide the voltage across it and these 2 voltage resulted (together summed they give up the original voltage) are required for each corresponding column and row controller chip to know how to bias the pixel matrix. If you bias the matrix to hard (larger voltages makes the transistors to switch at smaller imput levels, so they are triggered more easier) the crystals will change transparency level faster, thus you will get a darker screen or strange colors. If in a normal situation you will need 0.3Volts to drive a subpixel to fully block light (on it's specific wavelength) a harder biased matrix will require only 0.2V - for example. However as the voltage varies from 0 to 0.3volts in a normal case of color reproduction by a subpixel, you reduce the maximum range by forcing the corresponding mosfet transistor to do at 0.2volts what is was supposed to do at 0.3volts. The GPU and LVDS bridge will still send signal from 0 to 0.3 but the display's transistors won't display anything different from 0.2 to 0.3 range. Thus you get color alterations. If you find this problem in a display, it means this specific subsystem (contrast/crominance) has either failed or it's drived improperly. Inverted colors means the transistor in the crominance block is actually either dead or has a faulty connection. Instead of driving the display with 0.3 volts it used -0.3 voltage. All hell breaks loose. By no means user fixable. This subsystem is also located on the display module level. Older pda's or smartphones have this thing mounted on the ribbon cable coming out from the LCM itself. Those have a chance to be repaired without changing the display.
- white spots on the display. Most visible on white background. I repeat, spots, not bunch of little points (pixels). Those areas will still display colors, but with some distorsions. I didn't covered these when explaining the lcd display hardware. Well simply put the problem is like this. LCD backlights are made up from small white led's. However, the problem is that a led is a point like light source. Light is more intensive near the led and decreases as you move further. So, if led's were simply placed on the bottom of the screen , the upper part will be darker or the backlight won't be evenly spread. In order to solve this, manufacturers use some sort of polarizing filters in order to deflect light and "move" it more effectively. 2 polarizing filters are used, they are 2 foils containing some veeery small mirror like material that reflects light only when it passes though them at a specific angle. By using 2 filters (horizontal/vertical) and other specific materials, the backlight assembly can spread the light produced by 3-4 small leds on the whole screen surface. The foils are placed together in contact with each other and their final role is to direct the light straight into the display's matrix in order to fall vertically over the liquid crystals and through them - to you. IF however the backlight assembly is damaged due to mechanic shocks for example, those thin foils can bend or change their original orientation. Because of that, light won't be diverted vertically, won't pass though the crystals at the correct angle and thus.. you'll see spots on the screen. Another way for this problem to occur is water or dirt getting into the backlight assembly. Both can affect either the orientation of the polarizing filters or simply leave dirt on them. Either by mechanic shock or dirt, this problem can appear. I have a samsung omnia with this problem, i heard about 1/4 of them have it due to poor design of the phone's case against mechanic shocks.
Not user serviceable. I disassembled laptop screens in order to repair them or to change polarizing filters but it's a very stressful job. The smaller the screen the harder to repair it. I don't think it's even possible to find replacement backlight modules for phone screens. You either have to live with the problem or change the display.
- bad pixels. If you see a color dot (they are either green, red, blue or combinations of these) you have either one or couple of "dead pixels/subpixels". If you see a white/black dot - you have a full dead pixel. Well, what's happening there?
- single color dot. - damaged subpixel. This is basically a mosfet transistor that's blocked into conductive state and can't switch off. The pixel is working (not dead) but can't be turned off or assume variations in displayed color.
- single black dot - if all 3 subpixels that form a pixel are having the problem above, you get a black dot.
- single white dot - 3 dead subpixels. No power is getting in. Either 3 transistors commanding 3 subpixels (one pixel) are incapable of switching on or their 3 crystals are incapable of changing their state (rare scenario). In most cases, we get this from transistor failure.
- bunch of color dots - if they are located in close distance to each other, suspect a mechanical shock to the matrix. If they form a geometrical shape, suspect logical damage (transistors improperly driven or simply not powered on at all). If the pixels form a line across the screen - well, you diagnosed the problem incorrectly, those aren't your usual "dead" pixels, see above - you may have a row/column controller chip problem.
Dead pixel - user fixable? In some rare situations (i mean .. pretty rare) varying the screen content very fast is a way of attempting to unblock a locked transistor. In some lucky cases this will solve the problem. I had some success some time ago, in some cases it worked after couple of hours of displaying those rapid moving/alternating colors, in other cases it worked but the problem pixel got stuck again after some couple of weeks, in most cases it never worked at all. Worth a shot, couldn't harm to try. There are programs that do this job for you, something like "dead pixel fixer" or do a search on either marketplace or google for an app for your OS.
These are the most common problems with LCD displays (all sizes). Of course there are the "exotics" but most people will never see one. As you can see, there is not much to do or repair with smaller phone screens. No replacement subcomponents, too small...
TV screens for example can be disassembled and various components replaced or repaired individually. Hope it helps or gives you something to read in the morning when drinking your coffee.
Hey facdemol thanksfor that very informative post. As I have said before you are the man.
Related
Well this could be really e serious problem:
using my X7500 I noticed the display light level decreasing a little bit. I supposed it could be a wrong impression of mine. So I tried to push the upper side of metal case and I noticed the light coming up. Then I made a little pression on the same edge (near HTC brand as well the lower opposite side) and the light decreased again.
I assume there must be a problem with led position under metal cover. It's eneogh a little pression to have problem with light display. Maybe it could depend on "shock" due to the keyboard hook-up that could damage led connector inside...
Please help and tell me if you have noticed same problem...
Please any suggestions for this problem?
asci said:
Please any suggestions for this problem?
Click to expand...
Click to collapse
Sorry asci - not come across this problem with my Ameo.
Hi...
try to make a little pression under jog dial button...around that area and notice if something happen with brightnes.
Thank you for your courtesy.
asci said:
Hi...
try to make a little pression under jog dial button...around that area and notice if something happen with brightnes.
Thank you for your courtesy.
Click to expand...
Click to collapse
Tried the suggestion you made but no problems here either asci. Maybe your unit is faulty. Try returning it due to electrical shortage or something similar. It certainly does not sound normal.
asci said:
Hi...
try to make a little pression under jog dial button...around that area and notice if something happen with brightnes.
Thank you for your courtesy.
Click to expand...
Click to collapse
Yeah, tried that - absolutely nothing happening.
I turned it back to assistence...it seems to be an isolated case, and they could tell me when I'll have it back.
HTC customer care: bad assistence:
1. they didn't solve my problem yet;
2. they didn't answer to my mail.
I purchased an HTC X7500 on 21.05.2007. After two days it immediately showed some problems related to LCD display. In fact on making a light pressure all around display metal case, especially near the hardware buttons on left side, the LCD background light became weak as it loosed brightness.
I brought it immediately to a technical customer care for reparation. After two weeks it returned back but the problem related to display brightness still persist.
1. The backlight is weak and display is not so bright and not stable too as the very first time I tested it. Now when I connect 4 in 1 cable or mini USB one, and some time even when a set stylus in its lodging, by doing some little movement of the cables connected or of the stylus in its lodging, the backlight display increases to its normal brightness level for while after that it turns itself weak so that display colors appear not vivid and with a lack of brightness. Before testing it I verified that all backlight levels were set on maximum level with any power option.
2. When I browse through menu icons and select them (without launching application) their appearance is not stable and it seem to flicker.
3. If I set a white background on display it seems to be completely crossed by horizontal stripes and its appearance (color and brightness) is poor.
So today I had to come back to HTC customer care point to leave it for the second time in twenty day.
I would like to point out that I am a professional user and I’m really disappointed about it. I had to bring my device to a technical assistance point twice and the first time, I had it back not repaired.
Considering that, and also considering its high price and that it came with original unmistakable manufacturing faults, I am asking to HTC for a replacement of the device with another X7500 perfectly working.
Best Regards.
asci said:
HTC customer care: bad assistence:
1. they didn't solve my problem yet;
2. they didn't answer to my mail.
I purchased an HTC X7500 on 21.05.2007. After two days it immediately showed some problems related to LCD display. In fact on making a light pressure all around display metal case, especially near the hardware buttons on left side, the LCD background light became weak as it loosed brightness.
I brought it immediately to a technical customer care for reparation. After two weeks it returned back but the problem related to display brightness still persist.
1. The backlight is weak and display is not so bright and not stable too as the very first time I tested it. Now when I connect 4 in 1 cable or mini USB one, and some time even when a set stylus in its lodging, by doing some little movement of the cables connected or of the stylus in its lodging, the backlight display increases to its normal brightness level for while after that it turns itself weak so that display colors appear not vivid and with a lack of brightness. Before testing it I verified that all backlight levels were set on maximum level with any power option.
2. When I browse through menu icons and select them (without launching application) their appearance is not stable and it seem to flicker.
3. If I set a white background on display it seems to be completely crossed by horizontal stripes and its appearance (color and brightness) is poor.
So today I had to come back to HTC customer care point to leave it for the second time in twenty day.
I would like to point out that I am a professional user and I’m really disappointed about it. I had to bring my device to a technical assistance point twice and the first time, I had it back not repaired.
Considering that, and also considering its high price and that it came with original unmistakable manufacturing faults, I am asking to HTC for a replacement of the device with another X7500 perfectly working.
Best Regards.
Click to expand...
Click to collapse
Good luck and let us know how it turns out. I hope HTC doesn't become so big that they stop listening and taking care of their customer. I would hate to look for another high end phone manufacturer.
Arrived today...replaced.
Hi guys, I need some help here. I literally threw my wizard out of the window shaking out my bedsheets and it dropped three stories into the backyard.
When I turned it on again (the drop had opened the battery case), at first the screen was bright white, then turned darker and darker showing some sort of noisy stripes (static, not moving). When it goes into standby and is turned on again from there it does the same thing.
some facts:
- there is no visible crack in the display (neither from the side, I disassembled it)
- all buttons and the touchscreen are still responding (u can see that because the background lighting responds to them)
- the wizard is still accessible via usb
- I don't know whether the phone still works because I can't enter the pin w/o display.
It seems strange to me that the display should stop working while the touchscreen and the background lighting remain unhurt. I am thinking about replacing the display (only available together w/ the touchscreen and bg-lighting), but I am afraid that it might rather be a problem with the communication between the main unit and the display, even though there was no visible damage there.
Does anybody have experiences with that kind of behavior of the display?
Is the display that vulnerable that it breaks before the rest (light, touchscreen)?
I didn't find any cases similar to mine in the forum. If there are and my questions would be answered there, please direct me there.
Thanks for the help
ff
Try taking it apart, the force of inpact could have made a connection loose.
Disassembling I disconnected everything possible. Next thing would be to take apart the display/bglight/tscreen.
did you mean that? looks pretty fragile to me...
thx
yeah, I wouldnt mess with the display .. lol .. I meant a connection somewhere inside the device... like a loose ribbon or something
Yeah, seems hopeless. Guess I'll have to buy a new display and hope it works :-(
I'll post again once I got some results...
Problem solved
For the archive:
I exchanged the display and apparently only the screen was broken and the rest was unharmed.
I'd also like to add that two days ago (1 week after I repaired the thing) I dropped a plastic bottle on the phone in such a stupid angle that it broke the touchscreen. the next thing I will report here is whether it is possible to exchange the touchscreen only by doing some soldering.
a/t
I'm trying to develop a proof of concept product, but I'm having a hard time finding some of the materials I need to get the project started. The main thing I need is a large(1ft by 1ft, or 2ft by 2ft) clear capacitive screen with a matrix of LED's attached to the underside of the screen. I want the LED's to be able to glow three different colors, preferable Red, Yellow, and Green.
I don't want to get into the details too much at this point, but the overall objective is to have a flat, clear surface that can detect the weight(force) exerted by an object along with it's footprint, and then assign a certain color 'halo' around that object based off criteria that will have to be programmed into microprocessor somewhere along the way.
Does anyone know of a company that sells the kind of Tech I'm looking for?
beebop483 said:
I'm trying to develop a proof of concept product, but I'm having a hard time finding some of the materials I need to get the project started. The main thing I need is a large(1ft by 1ft, or 2ft by 2ft) clear capacitive screen with a matrix of LED's attached to the underside of the screen. I want the LED's to be able to glow three different colors, preferable Red, Yellow, and Green.
I don't want to get into the details too much at this point, but the overall objective is to have a flat, clear surface that can detect the weight(force) exerted by an object along with it's footprint, and then assign a certain color 'halo' around that object based off criteria that will have to be programmed into microprocessor somewhere along the way.
Does anyone know of a company that sells the kind of Tech I'm looking for?
Click to expand...
Click to collapse
Capacitive touchscreens don't detect weight/force, and will also not detect nonconductive objects (humans are partly conductive)... Sure you don't mean resistive?
Some of what you describe sounds VERY similar to how FTIR touch sensing (Microsoft Surface, etc.) works, which senses contact and not conductivity or force. Maybe use infrared LEDs to provide baseline contact detection and control the visible LEDs?
Rgb led array( like those in adv boards). Along with ir / laser net just above the surface( much better than resistive touch panels) will do the trick. I think u want to make interactive walls(like fancy walls in disco clubs, in which leds light up in the shape of object that is in front of it). Or there is another way, use a cam to detect the object, convert it to corresponding electric signals to light up rgb led array/wall.
HPD V10( WITH EXTREME MODS) ON FIKERT r.2.16+ .
You can get a display and then add your own hardware to that using gpios or IOIO or ADK.
I did something similar
Well if you look at sites like Newark.com you can find some of these components. I played around with some of these but never to actual practical use.
Simply put, I accidentally dropped my J3, and now large areas of bright color (such as the white of a search bar) spreads across the screen, depending on orientation, e.g. in Firefox, while in landscape, the white of the address bar bleeds onto the tab count and 3 dot menu, and in a game I play, the large bright blue wording against a back background bleeds across both sides of the image.
It isn't usage hindering as much as it is annoying, and the main thing worrying me is, will I HAVE to replace the LCD, or is it just a small issue that can be ignored? Would love a reply ASAP, as this is the only phone I have with service and if a replacement is necessary I would like to know as early as possible.
That's what happens with AMOLED displays unfortunately. Over time it will only get worse. The best thing you can do is get it replaced
Hi guys,
My s5's screen has broken and i need a new one. Also i want to buy that on the aliexpress but some lcd screens in the aliexpress are dont have brightness setting or dont have Samsung logo on the over. In fact, if you buy a orijinal lcd or a+ quality screen on the aliexpress, will you give link me? Thx.
I've installed a few of these 'Chinese Copy' screens and they are only worth doing if you are seriously short of money. Taking your points in no specific order:
The Samsung logo is always present on every one I've had. You never see it in the pictures because of some licensing condtion that says that you can only put the name on a completed product (or so I'm told). The screens will have a scratch-and-sniff patch covering the logo, which you have to remove (carefully) with the edge of a coin or something similar.
They have all had just two (or three) brightness settings ('dimming' in the test menu will show this) rather than being continuously variable
The colour rendition is crap
The color schemes thing where you select 'cimena', 'photographic' or whatever don't work. Can't remember official name for this
Doesn't support touch hovering
Some don't support multi-finger touch (some do)
The glass is little more than thin plastic and bends/breaks easily
They are significantly thicker than normal, so they won't sit in the housing properly. No amount of glue will make them sit properly (and they will bend anyway)
The screen area is several mm smaller in both dimensions. The space between the Samsung logo and the screen boundary is v noticeable unless it's a black screen
The TSP and glass can not be separated, even with specialist hardware
TL;DnR Don't bother.