EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: alxnik on December 01, 2013, 09:05:03 pm
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Hello Everyone
I was given a laptop to try to service which seems to have a design flaw.
The laptop is the Acer ICONIA 6120 Dual-Screen which although is a normal laptop, instead of screen/keyboard combo has 2 touch screens and a virtual keyboard. The problem with it is that the upper screen registers so called "ghost touches" (more info below). I researched the thing in the interwebs as well as I have done my own tests. Many people seems to have the same problem so I almost certain that this is a design issue, however acer seems to quietly deny this issue so the manufacturer is a dead end. People haven't found any fixes except from a guy who goes around forums asking for 20 euros to give the fix. Since I don't trust this guy, I will not go with this solution.
Now to the problem itself. The upper screen registers touches when the fingers of the user are not even close to the device, in a rate of about 30-40 touches/sec (roughly) which means that it gets crazy after a while. Below are the results of my tests on this.
1. When cold booted, the problem needs 3-4 hours to manifest (at least)
2. When the problem manifests, a hot reboot, a boot to a different OS (as in linux, not windows) doesn't fix the problem so it doesn't seem a software issue
3. The problem is only on the lower edge and the right edge
4. Installing/Uninstalling the acer drivers makes no difference
5. When the problem manifests, shutting down, removing/inserting the battery and rebooting, seems to fix the issue for about an hour or so.
Some people are suggesting to add some insulation between the touch interface and the screen but there is anecdotal evidence that this doesn't work.
In conclusion, I'm not afraid to open it up and do additional tests or mods in order to fix it, however I have no idea even theoretically, what could be the problem. I'd love to hear some (even wild) guesses on what could be the problem, in order to have a path to follow. Any additional tests I could do would be welcome
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Some touch screens have firmware that feeds the touch controller. I'm not sure how they could deploy an update to fix an issue like this. My guess if it takes a few hours is some kind of overflow to occur in the controller and the data wraps around to an invalid area. Could be bad use of pointers in the original C code.
There's a possibility that the bios on the computer uploads the code at power up. If that were the case Acer could fix it easily.
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Most likely a grounding issue, very common on capacitive touchscreens.
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Do the free stuff first.
Just let it sit there powered on. After 4 hours, does it fail?
Run it without the battery. Does it fail with out the battery.
Take out one memory SIMM if you can. Does it fail? If not try running it without the other SIMM. Does it fail?
If it is say 3 years or older, if you can get to the processor, try some new thermal paste. This may cost you a few drachmas.
Let us know if it gets fixed.
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Most likely a grounding issue, very common on capacitive touchscreens.
Never underestimate the ability of RoHS solder to break something.
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Some touch screens have firmware that feeds the touch controller. I'm not sure how they could deploy an update to fix an issue like this. My guess if it takes a few hours is some kind of overflow to occur in the controller and the data wraps around to an invalid area. Could be bad use of pointers in the original C code.
There's a possibility that the bios on the computer uploads the code at power up. If that were the case Acer could fix it easily.
Altough it sounds plausible, wouldn't a hot reboot fix it? Also it has the latest bios so I'm thinking that if it was easy, acer would have fixed it by now (1 year from latest bios). Lastly, I think it has something to do with enviromental factors too (heat?), as if I cold reboot it, it only needs 1 hour to restart the problem.
Most likely a grounding issue, very common on capacitive touchscreens.
I read that other people are thinking the same thing. So what is a grounding issue to a laptop screen? How do mod the thing to fix it?
Interesting thing in the design of the whole setup is that the laptop has a power supply followed by a DC power filter in a seperate enclosure. This gives me an impression that at the last moment they found out that noise from the input was unacceptable. Might this affect the touch in any way?
Do the free stuff first.
Just let it sit there powered on. After 4 hours, does it fail?
Run it without the battery. Does it fail with out the battery.
Take out one memory SIMM if you can. Does it fail? If not try running it without the other SIMM. Does it fail?
If it is say 3 years or older, if you can get to the processor, try some new thermal paste. This may cost you a few drachmas.
Let us know if it gets fixed.
Haven't tested these yet, the laptop is less than 2 years old and my guess is that these problems would manifest in other ways too. Nevertheless, I guess it doesn't hurt to try
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Haven't tested these yet, the laptop is less than 2 years old and my guess is that these problems would manifest in other ways too. Nevertheless, I guess it doesn't hurt to try
Less than 2 years old + Grease still in Europe = Still in warranty.
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Interesting thing in the design of the whole setup is that the laptop has a power supply followed by a DC power filter in a seperate enclosure. This gives me an impression that at the last moment they found out that noise from the input was unacceptable. Might this affect the touch in any way?
PSU noise certainly could affect the touchscreen, though it's highly unlikely this would be in a way which gets worse over time. I'd expect it to either work or not work.
More than likely, they designed the product without the filter, went EMC testing, failed, and had to come up with a fix at the last minute. That's the usual reason why ugly, obviously bolted-on filters end up being used in products.
It's easy to test, though. Run the laptop until it starts to misbehave, then pull out the power lead and run it off the battery for a while. If it still misbehaves, then it's not power supply noise. (At least, not noise from the external adapter... it could still be internally generated noise, but there's really no good reason why this should change with time).
Does it make any difference what the state of the battery charge is? Some mains supplies are actually quieter on full load than they are on part load. Charging a flat battery might cause more current to be drawn from the mains supply, which would put it into a quieter state. As soon as the battery is charged, the current draw reduces and the adapter gets a bit noisier. Highly unlikely, but not completely impossible.
What happens if you power the laptop from a different supply? Could you power it from a quiet lab supply?
I wonder whether there's some ongoing self-calibration going on which is eventually failing. There must be a sensitivity setting somewhere in the system; maybe there's a periodic calibration being carried out which is affected by temperature? When it starts to misbehave, stick it in the fridge for half an hour and see what happens.
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You said the problem appears always in the same spot? Does the problem appear when you have the device opened up? Also, is it possible to interchange the two touchscreens? The description sounds like temperature problem to me.
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I'm about to get one of those to try to fix that problem, client will bring it in 2 weeks, for now the information I have is only that the touch screen goes crazy and that is a common issue. My guess.... Cold solder. I've seen this same issue on tablets with DC Jack cold solder problems. But since I'll get my hands on it only in 2 weeks, I can only wonder...
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Interesting thing in the design of the whole setup is that the laptop has a power supply followed by a DC power filter in a seperate enclosure. This gives me an impression that at the last moment they found out that noise from the input was unacceptable. Might this affect the touch in any way?
PSU noise certainly could affect the touchscreen, though it's highly unlikely this would be in a way which gets worse over time. I'd expect it to either work or not work.
More than likely, they designed the product without the filter, went EMC testing, failed, and had to come up with a fix at the last minute. That's the usual reason why ugly, obviously bolted-on filters end up being used in products.
It's easy to test, though. Run the laptop until it starts to misbehave, then pull out the power lead and run it off the battery for a while. If it still misbehaves, then it's not power supply noise. (At least, not noise from the external adapter... it could still be internally generated noise, but there's really no good reason why this should change with time).
Does it make any difference what the state of the battery charge is? Some mains supplies are actually quieter on full load than they are on part load. Charging a flat battery might cause more current to be drawn from the mains supply, which would put it into a quieter state. As soon as the battery is charged, the current draw reduces and the adapter gets a bit noisier. Highly unlikely, but not completely impossible.
What happens if you power the laptop from a different supply? Could you power it from a quiet lab supply?
I wonder whether there's some ongoing self-calibration going on which is eventually failing. There must be a sensitivity setting somewhere in the system; maybe there's a periodic calibration being carried out which is affected by temperature? When it starts to misbehave, stick it in the fridge for half an hour and see what happens.
PSU is in the inprobable bin for me, although I am in a "you never know" state. You have just shoved it further in the inprobable bin. Nevertheless interesting info, I think first order of the day is to put the psu on a electronic load and measure it on the oscilloscope, even as a test for test's sake.
You said the problem appears always in the same spot? Does the problem appear when you have the device opened up? Also, is it possible to interchange the two touchscreens? The description sounds like temperature problem to me.
Quite possible to be a temperature issue, although I can't see a heat source on the lid/upper screen. Haven't opened it up yet because I have a heavy hand on these things and end up breaking plastics here and there. I want to do it after I gather all the possible info. Changing the 2 touch screens isn't possible as they are attached to the respective upper and lower frames.
I'm about to get one of those to try to fix that problem, client will bring it in 2 weeks, for now the information I have is only that the touch screen goes crazy and that is a common issue. My guess.... Cold solder. I've seen this same issue on tablets with DC Jack cold solder problems. But since I'll get my hands on it only in 2 weeks, I can only wonder...
Would CERTAINLY like to hear from you in 2 weeks time if I haven't fixed it until then. Cold solder is certainly one of the things to watch for, but something must be very wrong in the QA process to be so common
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If it manisfests over time/with hot laptop, might be a cooking cap in the PSU/local decoupling to the chip, or dodgy tantalums..
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Cold solder is certainly one of the things to watch for, but something must be very wrong in the QA process to be so common
Well, most laptop motherboard problems I've seen are due to cold or insufficient solder. There is a guy on youtube telling people to open the Acer Iconia and put a double tape to pressure the touchscreen against the LCD frame but some viewer posted that the problem came back after a while, so I don't believe the tape solved the problem in the first place, I guess the guy changed the screen status just by manipulating it. Sometimes it happens when we disassemble a dead laptop suffering from BGA cold solder an it starts working again, just because we removed the motherboard out of the chassis, but that doesn't mean the problem is solved.
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I'm a hardware person,so may be barking up the wrong tree,but can you swap the two touchscreens in software,so you can check if it really is a hardware fault,or something silly in how the Computer reads the particular touchscreen?
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this smells of a static charge accumulation problem...
capsense touch screens work on charge dispersal principle. if the common charge on the display rises they re-calibrate. There may be a point in time when the calibration can no longer compensate... that corner/ side may have a bad grounding tab.
you say that a full powerdown / battery removal solves the problem. i think it is not the power removal in itself or the battery removal , but something you do physically to the laptop at that point. like for hotboot you do not close the lid , but for a battery swap you do as you need to flip the machine upside down...
closing the lid may have the main machine body touching the top rim of the screen discharging it enough so that this works again. or simply because you flip the machine upside down it discharges through the work surface...
do a simple test : when the problem occurs. close the lid , then flip the machine upside down so the top panel touches the table. let sit for 20 seconds. then flip machine back over , open lid and power up.
see what happens...
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capsense touch screens work on charge dispersal principle. if the common charge on the display rises they re-calibrate. There may be a point in time when the calibration can no longer compensate... that corner/ side may have a bad grounding tab.
Makes sense, one of the things that client told me is that the problem goes away for a few hours when he opens the laptop completely (both LCDs flat) and he cleans the LCDs with an anti-static cloth. I think it's not the cleaning that makes it go away, but the pressure, thus a grounding issue. Anyway, just wondering again since I've never seen this laptop personally.
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Cold solder is certainly one of the things to watch for, but something must be very wrong in the QA process to be so common
Well, most laptop motherboard problems I've seen are due to cold or insufficient solder. There is a guy on youtube telling people to open the Acer Iconia and put a double tape to pressure the touchscreen against the LCD frame but some viewer posted that the problem came back after a while, so I don't believe the tape solved the problem in the first place, I guess the guy changed the screen status just by manipulating it. Sometimes it happens when we disassemble a dead laptop suffering from BGA cold solder an it starts working again, just because we removed the motherboard out of the chassis, but that doesn't mean the problem is solved.
There are mixed reviews about the youtube guy.
However I started a test which runs for some hours now, I cracked open the lid frame (which actually is pretty simple) seperating the touch from the screen. This guy is using non conductive tape so I am guessing that by seperating them I simulate his solution. I've left it for some hours, will check it later again.
this smells of a static charge accumulation problem...
capsense touch screens work on charge dispersal principle. if the common charge on the display rises they re-calibrate. There may be a point in time when the calibration can no longer compensate... that corner/ side may have a bad grounding tab.
you say that a full powerdown / battery removal solves the problem. i think it is not the power removal in itself or the battery removal , but something you do physically to the laptop at that point. like for hotboot you do not close the lid , but for a battery swap you do as you need to flip the machine upside down...
closing the lid may have the main machine body touching the top rim of the screen discharging it enough so that this works again. or simply because you flip the machine upside down it discharges through the work surface...
do a simple test : when the problem occurs. close the lid , then flip the machine upside down so the top panel touches the table. let sit for 20 seconds. then flip machine back over , open lid and power up.
see what happens...
From all the replies, I can definitely say that yours fit my test results so far best. My next tests will be along this theory for sure.
I'm a hardware person,so may be barking up the wrong tree,but can you swap the two touchscreens in software,so you can check if it really is a hardware fault,or something silly in how the Computer reads the particular touchscreen?
Being a software guy, I think I have excluded all the possible software faults, although I don't think it's possible to swap the touch screens in software.
By the way, I got around testing the PSU, and at 50%-90% loading it had 1Vpp ripple before the filter and a nice <100mVpp after the filter (the filter seems mandatory). Even at 90% there seems to be no serious voltage dip.
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Could it be EMI from the CCFL inverter that's charging up the screen?
By the way, I got around testing the PSU, and at 50%-90% loading it had 1Vpp ripple before the filter and a nice <100mVpp after the filter (the filter seems mandatory). Even at 90% there seems to be no serious voltage dip.
1Vpp on a 20(?)V supply is only 5%, and it's going to be regulated down to far lower voltages by a bunch of buck converters so that's reasonable.
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Could it be EMI from the CCFL inverter that's charging up the screen?
By the way, I got around testing the PSU, and at 50%-90% loading it had 1Vpp ripple before the filter and a nice <100mVpp after the filter (the filter seems mandatory). Even at 90% there seems to be no serious voltage dip.
1Vpp on a 20(?)V supply is only 5%, and it's going to be regulated down to far lower voltages by a bunch of buck converters so that's reasonable.
I like the EMI theory. I will go to the shops later to get some tape of some kind. I think I will add some copper tape in the mix to test it, although I haven't checked if it is CCFL or LED.
Yes it is a 20V (19.6 to be exact) PSU, and most probably it doesn't directly power anything, but nevertheless seeing 1Vpp on the scope is kinda ugly/stressful :o
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I don't think anyone uses ccfl anymore.
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Could it be EMI from the CCFL inverter that's charging up the screen?
By the way, I got around testing the PSU, and at 50%-90% loading it had 1Vpp ripple before the filter and a nice <100mVpp after the filter (the filter seems mandatory). Even at 90% there seems to be no serious voltage dip.
1Vpp on a 20(?)V supply is only 5%, and it's going to be regulated down to far lower voltages by a bunch of buck converters so that's reasonable.
I like the EMI theory. I will go to the shops later to get some tape of some kind. I think I will add some copper tape in the mix to test it, although I haven't checked if it is CCFL or LED.
Yes it is a 20V (19.6 to be exact) PSU, and most probably it doesn't directly power anything, but nevertheless seeing 1Vpp on the scope is kinda ugly/stressful :o
The copper tape might do the trick.Put it on the egde of the panel and onto the side of the hinge/support.Fixed an old pos terminal some years ago that had similar problems with calibration.
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There is a topic in notebookforums saying it's software related: http://www.notebookforums.com/t/241914/acer-iconia-6120-6886-484g64ns-real-ghost-touch-solution (http://www.notebookforums.com/t/241914/acer-iconia-6120-6886-484g64ns-real-ghost-touch-solution)
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There is a topic in notebookforums saying it's software related: http://www.notebookforums.com/t/241914/acer-iconia-6120-6886-484g64ns-real-ghost-touch-solution (http://www.notebookforums.com/t/241914/acer-iconia-6120-6886-484g64ns-real-ghost-touch-solution)
I've read through it and according to my experience they are not correct >:D. The acer software seems to delay the problem for a while (drivers which calibrate the thing?) but it certainly was not fixed.
After leaving the laptop on for ~20 hours with the touch seperated from the screen, no ghosting appeared. About 4 hours ago I added some aluminium tape along the edges which I grounded. So far no ghosting. I am leaving on a business trip so I left it on and will check on it again in 3 days. If it is either EMI or bad grounding I think it should be fixed. Fingers crossed!
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I was curious about what touch panel controller they were using (try to cross-ref with other models/manufacturers and see if they don't have this issue) so tried to find a schematic and apparently one exists but only on sites wanting to sell one or foreign-language forums you have to figure out how to download from... |O
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There is a topic in notebookforums saying it's software related: http://www.notebookforums.com/t/241914/acer-iconia-6120-6886-484g64ns-real-ghost-touch-solution (http://www.notebookforums.com/t/241914/acer-iconia-6120-6886-484g64ns-real-ghost-touch-solution)
Some forums say its a software problem,some say ts a hardware problem.Some claim to have fixed the problem ,only for it to return a few weeks later .
Here is the service manual/guide for anyone interested :
http://uploaded.net/file/4a19i3sx (http://uploaded.net/file/4a19i3sx)
EDIT: i have tested the file for viruses and spyware, but i still wouldn`t trust any pdf .Open in sandboxie or a VM if you use windows.
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Hi!
I felt the need to participate for this discussion. I've owned the Iconia for almost two years now, having the ghost touch issue and tried every possible solution available.
Here's my obsevations:
1. For the upper screen, instead of foam tape, I used a transparent plastic sheet between the touchscreen and lcd-panel. That removed the ghost touches from the upper screen, but moved the issue to the lower screen, which was formerly free of ghost touches.
2. If I remove the plastic sheet from upper screen, the ghost touch issue returns to the upper, but moves away from lower screen.
3. Cleaning the screens properly from dust and grease makes the touch work a bit longer than usual before the problem returns.
4. Using aluminium/copper tape to conduct electricity to ground from screen seems to have no effect (Or I'm using it wrong, any advice how?)
5. Using a vacuum cleaner (!) connected into outlet in same room seems to launch ghost touches.
6. Connecting the machine into grounded outlet seems also lengthen the time before ghost touches appear.
7. Using the old VGA driver (as suggested) have a minor or no effect.
8. Setting the machine to sleep and the wake up cures the ghost issue for a little while.
9. When the ghost touches appear, there are NO WAY to make them stop unless you shut down computer / put it to sleep.
After all I've tried. The issue remains and that's why the machine is unusable for task-critical purposes (as midi-controller, musical instrument, games etc...), but usable for web browsing and photo editing, where you could easily take a pause between the work.
I really hope someone is going to find out the root for these ghost touches, because I'd really like to use the machine without the fear of losing the control!
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Here is the service manual/guide for anyone interested
Not what I was looking for but thanks. The OEM model is Compal LA-6392P, for anyone who might know where to look. (IMHO Compal tends to put out the most models in need of repair... Inventec and Quanta are a bit better.)
5. Using a vacuum cleaner (!) connected into outlet in same room seems to launch ghost touches.
Vacuum cleaner = high speed brushed motor = wideband RF noise source. Something in the screen is clearly acting as an antenna and picking up enough signal to disrupt the touchscreen controller, probably confusing the firmware its running.
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Properly ground the laptop then try. Is the case metal or plastic?
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The case is non-conductive. How do I properly ground the machine? A wire from the laptop ground to a water sink?
I forgot to mention; these ghost touches happen even on battery power, without cable plugged in mains.
Also, for example with the plastic sheet between lcd and touchscreen, the problem stayed away over a week. So, I personally believe the problem consists of combination of different issues, i.e. bad grounding+EMI+noise from charger+dirt on the screen.
cheers
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See if you can use software to adjust the sensitivity of the screen. If thats not possible search online and see if you can adjust the sensitivity with some variable resistors. Or even get in the touch screen input with a oscilloscope to see whats going on.
Is the screen resistive or capacitive?
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Touch screens are capacitive.
The laptop has no keyboard, just two touchscreens which open like a book. It's a special model by Acer which was on production just for a short time. Acer has abandoned the support for this model and there will be no firmware updates for the touchscreen, and no way to adjust the sensitivity software wise. Inside I found a touch controller (or a module which I believe that is touch controller), which is a small 2x1cm PCB.
Windows require no drivers for touchscreen to work. Are there somewhere in windows registry some parameters for touchscreen sensitivity?
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For it not to require any special drivers the touchscreen probably is connected to and acts like a USB or PS/2 mouse. If you want to go down this troubleshooting route then first you'll need to figure out what the touchscreen controller is (which is the main reason why I wanted to find the schematic.)
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I think there is a "touchscreen and pen controls" setting in mycomputer/properties
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Ok, i small update after investigation;
I'm pretty sure this design flaw is about interference between LCD and touch panel. I noticed a really small gap between my plastic sheet and LCD on the side, corrected that and now the computer have been ghost-less for several days.
I even used the vacuum cleaner yesterday with my computer on and there were no ghost touches.
Any idea why the contact between LCD and touch panel is so big issue? How the problem is handled in other computers without this issue (Ipads, HP touchsmarts, Mirosoft surfaces etc...). Why it is Acer that seems to have this problem on many of its computers, especially Iconia series (My dualscreen 6120, 700 and 500-series and maybe also others).
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Any idea why the contact between LCD and touch panel is so big issue?
Noise is being picked up by the LCD which is then conducted to the touch panel.
How the problem is handled in other computers without this issue (Ipads, HP touchsmarts, Mirosoft surfaces etc...). Why it is Acer that seems to have this problem on many of its computers, especially Iconia series (My dualscreen 6120, 700 and 500-series and maybe also others).
Bad design/oversight. Or if it worked before and now doesn't, could be some aging components with marginal tolerances.
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Ok, i small update after investigation;
I'm pretty sure this design flaw is about interference between LCD and touch panel. I noticed a really small gap between my plastic sheet and LCD on the side, corrected that and now the computer have been ghost-less for several days.
I even used the vacuum cleaner yesterday with my computer on and there were no ghost touches.
Any idea why the contact between LCD and touch panel is so big issue? How the problem is handled in other computers without this issue (Ipads, HP touchsmarts, Mirosoft surfaces etc...). Why it is Acer that seems to have this problem on many of its computers, especially Iconia series (My dualscreen 6120, 700 and 500-series and maybe also others).
Hi there! Can you explain exactly where is this gap and if it is still working, so we can reproduce it.
I think I found a possible solution for this problem. I hope it will be permanent this time. It has been 5 days since I found it and it has been a relief not to have to stop to do anything all the time because of it.
After I installed the old drivers this problem got much better but still happening, and as all of you know it drives any person crazy. As it happens in different systems (Windows 7, 8 or linux) I concluded that it was a hardware fault. Last week I just got tired of it so I took the back chassis and touched different cables and areas with laptop on. I found that touching 2 cables next to the hard drive the ghost touch would start and touch them with the metal case would produce the same bad effect. So I moved the cable of the green arrow to the space next to the hard drive and put a tape holding it at the same place. It has been 5 days with no ghost touch. It did happens once when I moved the laptop so I opened it again and one of the cables did move and was touching the chassis. I put it on place again and the ghost touch was gone.
I hope it would be permanent, share it in all forums you can find. I ask all of you to try different methods to insulate these cables from each other and the chassis so we will get rid of ghost touch forever.
Good luck for all and share as much as you can.
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Pictures? We like pictures...
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:-+
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Heeey, I remember this thread, I started it!
FYI, In my case after an aluminium tape for grounding followed by tape for insulation (against anything else other than the ground), the laptop seemed to be rock solid. Since it wasn't mine (lenovo ftw!), I gave it back and haven't heard from the owner about any problems since. So in the end, this solution seems to work. :-//
4. Using aluminium/copper tape to conduct electricity to ground from screen seems to have no effect (Or I'm using it wrong, any advice how?)
Aluminium tape has plastic insulation on both sides. In order to expose the actual aluminium, I burned the plastic on the top side a little bit with an old soldering iron where it touched the ground until I could test continuity with my multimeter
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Here is the service manual/guide for anyone interested
Not what I was looking for but thanks. The OEM model is Compal LA-6392P, for anyone who might know where to look. (IMHO Compal tends to put out the most models in need of repair... Inventec and Quanta are a bit better.)
5. Using a vacuum cleaner (!) connected into outlet in same room seems to launch ghost touches.
Vacuum cleaner = high speed brushed motor = wideband RF noise source. Something in the screen is clearly acting as an antenna and picking up enough signal to disrupt the touchscreen controller, probably confusing the firmware its running.
I found the schematic for anyone still interested.
http://kythuatphancung.com/uploads/download/9b410_Compal_LA-6392P.pdf (http://kythuatphancung.com/uploads/download/9b410_Compal_LA-6392P.pdf)
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Weird. Where the keyboard matrix on a normal laptop would be connected to the EC (row/column lines), they've instead connected the touchscreen. That doesn't give any hints on what the touchscreen controller is unfortunately, nor how the keyboard works. (Is a virtual keyboard emulated by the touchscreen controller or BIOS/SMI so it looks like a regular keyboard, or does it require a special driver?)
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Hi!
The tip moving the cables inside the machine is great! I tried it on my machine last weekend, and it seems somehow working, but not as Farinello suggested. In my case, if I leave bottom cover open when running the machine, the ghost touches stop if I touch the two cables indicated in Farinello's picture.
So, the wires maybe need to be grounded and/or shielded? Moving the cables so they don't touch the metal doesn't help. I'm thinking to try the shielding first (coated aluminium) when I have free time. I'll report back if that helps.
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Weird. Where the keyboard matrix on a normal laptop would be connected to the EC (row/column lines), they've instead connected the touchscreen. That doesn't give any hints on what the touchscreen controller is unfortunately, nor how the keyboard works. (Is a virtual keyboard emulated by the touchscreen controller or BIOS/SMI so it looks like a regular keyboard, or does it require a special driver?)
I found this on a russian forum, i don`t know if its correct or not :
Quote : That is on the top screen controller Cypress Semiconductor CYTCB4S-01001, and at the bottom Cypress Semiconductor CYTCB4S-01002 (at least for me).
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So, the wires maybe need to be grounded and/or shielded? Moving the cables so they don't touch the metal doesn't help. I'm thinking to try the shielding first (coated aluminium) when I have free time. I'll report back if that helps.
Answering to myself: no, shielding the cables with coated aluminium didn't help. Actually it made the problem worse. After coating there were nothing but ghost touches as soon as laptop was on. So, bad idea.
One thing that seemed to work, at least for now, is to insulate the bottom cover ground points. There are two metal slices inside bottom cover which touch inside the laptop when cover is on. I put some tape over the metal slices so they don't touch anything inside the machine. After that, no ghost touches. But, as with previous fixes, it may help just for some days.
Thank you for the touch controller schematics! It seems the dual screen Iconia is the only machine with this touch controller.
Cheers
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Hi!!!! I will try to insulate this to metal parts too. Did it work for any of you?
Thanks
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Hi Guys! I just open the top screen and found another metal foil parts and insulate them. When I was assembling the screw on the front right part of the top screen I could see that ghost touch would happen madly. So I took this screw off and ghost touch stopped again. Any idea of why it is happening?
Thanks
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Hi again!!! This is a first time in 2 years that I have no ghost touch for more than a week. After I took off the right bottom side screw of the top screen ghost touch disappeared for good. Any of you would know why? thanks
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I had a laptop with EMI issues on the touchscreen in the past.
http://youtu.be/u3lzM5OO7CE?t=1m30s (http://youtu.be/u3lzM5OO7CE?t=1m30s)
Someone told me that Apple did a big research on capacitive touchscreen and EMI when designing the first iPhone and the first phone with multitouch. It have serious shielding + filtering on the phone and on the charger.
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Sounds like you may have some 'over compression' of the screen where the screw was removed.
Perhaps some packing or insulation under/around that area, or a stub of plastic from the bezel ?
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HELLO
I HAVE A PROBLEMS WITH THE ICONIA
I TREATED WITH TWO SERVICES AND WITHOUT SOLUTION FROM ACER.
I WANT TO KNOW HOW WAS THE CABLE SOLUTION 1 AND 2 REMOVING THE RIGHT INFERIOR SCREW IT ALSO WAS RECOMMENDED AT THIS SITE: http://senpa.us/acericonia6120ghostfix.html (http://senpa.us/acericonia6120ghostfix.html)
WHAT DO YOU THINK ABOUT THAT TAPE FO ISOLATION ?
WHEN IT'S COLD ANOTHER BELOW 22 º C MY ICONIA NOT START, BUT IF I PUT SOME HREAT WITH A HEAT GUN ON CPU IT STARTS NORMALLY. IT COULD BE A CPU FAILURE AND MAY BE WORTH ANOTHER TEST WITH A NEW CPU?
MANY PROBLEMS WITH THIS MACHINE , A PITY, BECOUSE I LIKED THE CONCEPT OF 2 TOUCH SCREENS.
THANK YOU VERY MUCH FOR ADVISE. SORRY FOR MAY ENGLISH
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Hi!!!
After I took the screw off, no ghost touch for more than a month.
:-+
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Hi!!!
After I took the screw off, no ghost touch for more than a month.
:-+
Hi!
I can confirm Farinellos solution. After removing the screw on the bottom right side of the upper screen, just a bit over the hinge, under the black tape, the machine have been rock solid.
To Farinello:
You are the first one to find a complete solution to this problem after almost two years of pointless fixes. I would like to send you a small reward by paypal. Can you send me a private message with your paypal address?
Thank you!
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Very interesting. I suppose the "proper" fix would be to use a plastic screw in its place...
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Hi guys. First post here. I too have the 6120 and, although my ghost-touch issue hasn't been as severe as some of yours, it is indeed annoying.
But what is infinitely more annoying is Acer's contempt for their customers. This was an expensive laptop- could have got much better spec for the money, but I bought it on the strength of a previous good experience with an Acer netbook.
It is high time Acer put their customers' satisfaction ahead of their shareholders' interests. Otherwise one day there will be no Acer!
Such a shame- good product let down by "We've got your money, now sod off!"
Now just one question (and I hope someone from Acer's PR dept. reads this)- Based on the last 4 pages of posts, will you EVER consider buying an Acer again?
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Now just one question (and I hope someone from Acer's PR dept. reads this)- Based on the last 4 pages of posts, will you EVER consider buying an Acer again?
Hi!
This is true. A bad experience with one single product easily destroys the whole brand's reputation. I bought this dual screen Iconia laptop in sale, and paid only 400 euro for it. I really like the concept, but that's all it is; a concept product, not meant to be used for mainstream customers. What amazes me is that why Acer could not find this single screw that was the root of all evil?
If I would buy a new standard laptop, it would definitely be something non-Acer. But if Acer puts out a new intriguing concept machine of kind that no one else makes, I probably would buy it (on sale). After all, this struggle with ghost touches have been almost a hobby for me for two years and I kind of started to enjoy taking the machine apart again and again :)
BTW, after screw removal, I had one ghost touch experience in lower screen, that required restart. So the cancer is not cured, although medicine was quite effective.
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Keep in mind that this laptop is actually designed by Compal.
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Hi guys!!!
After some tests I found the problem. After I took the screw off (mentioned before) ghost touch stopped to be a big pain, happening few times a week instead of 5 or 6 times every hour. I did some other tests and I found that putting an electrical tape insulating the metal part were the screw fits, closing the top screen and putting the screw back stops ghost touch. At least it did happen to me (24 hours without ghost touch). I feel that the laptop is running faster and the fan is quiet. I hope it helps all of you. I give some feedback in few days.
:-+
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Two days and no ghost touch... so far so good
:-+
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Hi guys!!!
Several days and no sign of ghost touch!!! It is incredible as it was so simple and anybody found it sooner. Now I am able to use this laptop and not be afraid of moving it around. I hope all of you are able to use this solution and be as happy as I am.
:-DD
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I have been three weeks with no ghost touch. I think I found a permanent solution. I hope others can enjoy it too. :-+
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HELLO FARINELLO
THANKS VERY MUCH FOR YOUR CONTRIBUTION ,
COULD YOU EXPLAIN IN MORE DETAIL HOW TO ISOLATE THE AREA OF METAL SCREW TO AVOID THE GHOSTS TOUCHES ?
YOU SHOULD OPEN THE SCREEN?
TAKE OUT THE SCREW IMPROVED BUT SOMETIMES APPEARS
HOW WAS WITH TAPE FOR ISULATION ? IS STILL WORKING ?
THANKS
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Hi!!!
Since I used the electrical tape ghost touch just vanished. I did take the two front screws off, I opened the top screen, I got a black electrical take and I covered the metal square of metal on the right bottom (where the right screw fits), then I closed the top screen and put back both screws. After that ghost touch is gone. If any of you send a picture of the top screen opened I send it back with an arrow on the place you need to put the tape.
I hope all of you get what I got a good laptop with no ghost touch. Now I can use my laptop, I even installed win 8 and its working really smooth.
Any of you now if I can use the PCIe free slot to fit an sdd hdd? Does it work on this laptop?
Thank you and good look!!!
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HELLO FARINELLO
THANK YOU FOR YOUR CONTRIBUTIONS
AS YOU PROPOSED I SEND 3 PHOTOS SO YOU CAN INDICATE ME THE PLACE TO PUT ELECTRICAL TAPE.
QUESTIONS
1 – WAS THE SOLUTION 100% EFFECTIVE ? IT STILL WORKING ?
2- HOW MANY LAYERS OF ELECTRICAL TAPE SHOULD BE PLACED ?
3- THE TAPE MUST BE PUT OVER THE METAL PLATES BOTH RIGHT AND LEFT OR JUST OVER THE RIGHT ?
4-TAPE MUST BE PLACED IN ANY OTHER PLACE (AT SIDES OF THE LCD?
5-PUT PICTURES OF A VIDEO THAT I FOUND ON THE WEB AND I DO NOT ENCOURAGE EVEN OPEN THE SCREEN. IT IS VERY DIFFICULT ¿
I EXPECT THE ANSWERS
THANK YOU FOR YOUR KINDNESS AND CONTRIBUTIONS.