Strange N800 problem. (is it the hardware?)
 

Hello! I've searched around but I haven't been able to find anyone else who has posted about this problem and I am desperate for some help.

I have an N800 that had worked fine. Now the touch screen stops responding unless the power button is pressed, and then it responds for 10-15 seconds before dying again. To clarify a bit more, I can turn the device on and navigate most the menus as long as I press the power button every 10-15 seconds to keep the screen active. One more issue that may be related is that the audio is also no longer functioning.

I've removed the SD cards, cleared the memory, restored the defaults, and have tried flashing the device to os2007, an older os 2008 and the most current release. The only thing that changed the problem was that with os2007, pressing the power button wouldn't reactivate the screen.

If the problem wasn't so strange I'd chalk it up to the hardware being fried and give up but I'm hoping someone else might have another suggestion. Any help is appreciated!

Re: Strange N800 problem. (is it the hardware?)
 

It might be a loose connector... Instead of pressing the power button try squeezing the case near the power button (front-back).
It has been a long time since I had to open-up my n800 to replace the power connector, but I recall that the screen has two connections - a large one in the upper right and a smaller one somewhere near the power button.

Re: Strange N800 problem. (is it the hardware?)
 

It sounds like hardware. I had similar (though not identical) problems with my N800; they eventually went away, and the only thing I could think of was that something got wet and dried out later. Unfortunately, your problem sounds worse.

Re: Strange N800 problem. (is it the hardware?)
 

Thanks for the ideas guys. Couldn't flex the case much and the farthest I was able to get on the inside was popping the silver cover off. I'm going to have to invest in a small enough hex wrench to open it up and take a proper look, hopefully the problem will be more obvious then!

Re: Strange N800 problem. (is it the hardware?)
 

It's not a hex wrench, you need a torx screwdriver t6.

Re: Strange N800 problem. (is it the hardware?)
 

I have a similar problem on occasion.

The touch screen stops responding for me, and it's usually after something was sitting on top of it for a long while.

If the touchscreen controller gets too long a stream of continuous input, I think it shuts down to save power.

I use the power button to bring up the menu, and the d-pad to select "Lock Screen".

After unlocking the screen, the touchscreen works fine again.

Re: Strange N800 problem. (is it the hardware?)
 

Thanks for the continued suggestions! I tried locking the screen but the entire device goes unresponsive save for holding the power button to turn it off.

One thing that I was surprised to have worked was if I start streaming an internet radio station the device works perfectly so long as the station is streaming. If the connection is lost though, the device goes unresponsive until switched off again. Does anyone know of a similar program that I could run to keep the screen responsive that doesn't require being online?

Thanks again!

Re: Strange N800 problem. (is it the hardware?)
 

If you are receiving internet radio, your audio must be working again. Your first post said that it wasn't functioning. What did you do just before it started again? Have you tried using the same media player to play music stored on the N800 or on a data card? Were you using the built-in Media Player or some other?

The thing that really puzzles me is that I have the opposite experience with the built-in Media Player. It is the most likely app to cause a freeze-up of my N800. Usually this happens when I try to select a menu item before the app is ready, such as when it is refreshing the menu. Have you tried slowing yourself down? (Pause briefly before making your next stab at the screen.)

The Images app is another one that sometimes freezes on me. It happens when I try to load or edit pictures faster than the N800 can handle. The Nokia 770 is much worse in this way - significantly, its processor is slower and less powerful than the N800's. It sounds to me as if you might be expecting your N800 to work faster than it is capable of doing. You might also have an overcrowded root file system (rootfs).

Do you have a lot of apps installed? Do you tend to open several at a time? Are you booting from the internal flash or from a media card partition? How much swap space do you have available? (Swap is also called virtual memory.) All of these could make a difference. So:

remove apps that you don't need;

activate more virtual memory, or create a large swap partition on one of your media cards;

limit yourself to having three or four windows open at a time;

and slow down a bit.

Depending on how you installed apps in the first place, the associated .deb files could be taking up a lot of space somewhere in the /var directory, even after you have uninstalled the apps. You could find out more about this by searching the forum.

Like you, I can usually close the offending app and regain responsiveness after pressing the power switch. I move up and down the resulting menu a couple of times, using the navigation button, and then select "Cancel". That usually does the trick. I don't have to do this very often, since learning to avoid the habits that make the device freeze.

If you haven't set up a bootable rootfs on a media card, that is something that can improve performance tremendously. If you search on "MMC boot", "SD boot" or "bootmenu", you should be able to find information about this. Bunanson has written some extremely helpful step-by-step guides.

I hope that some of this will help.

Re: Strange N800 problem. (is it the hardware?)
 

Well I have no idea how to solve your problem, but lets try to isolate it. When you say the screen is unresponsive - is the screen lit up ? does it light up ? does it make a click sound ? what do you see when you vnc into the tablet ?
you say no audio - both earphones and speakers ? what about bt earphons ?
I've heard reports where people had something fall between the bezel and the screen, causing false input. Maybe try to use it with the bezel off.
Streaming media "fixes" the problem. What about Transmission (torrents application) ?

Re: Strange N800 problem. (is it the hardware?)
 

Sounds like a damaged touch screen causing the dsp to work continuously. Streaming music causes the dsp to break away from the touch screen to process the music. Clean under the bezel and look for damage with a 20x loupe.

Re: Strange N800 problem. (is it the hardware?)
 

And what has the dsp to do with the touchscreen? Where did you get that information from?

Re: Strange N800 problem. (is it the hardware?)
 

I was under the impression that the dsp is used to filter the presses to determine stylus vs finger and to focus the X Y coordinate. Is the touchscreen driver open?

Re: Strange N800 problem. (is it the hardware?)
 

It's a kernel driver, look for tsc2301.c and tsc2500.c

Re: Strange N800 problem. (is it the hardware?)
 

Try re-flashing. Always works for me.