Tablet Computer Turns Itself 'on'

[MrAl]

Hello there,

I have a new problem with a tablet computer i purchased a while back. It is now turning on by itself. It did not appear to do this when new, but no new software was downloaded for it over the past say couple months yet it started about three weeks ago.

There are two ways to "shut it off", one way is to put it into 'sleep' mode, the other way is to do a full power down. In sleep mode, the cpu i think still runs at least now and then, and if you press the power button quickly the unit will turn on completely in less than a second. The other way is to do a full power down. When that is done, to turn it back on you have to push and hold the power button for about 2 seconds, and then it boots up. Booting takes about 10 to 15 seconds.
To do a full power down, you have to press the power button for 2 seconds rather than quickly, and then you get a message on screen that asks if you really want to power down, and you press "OK" to fully power down. It takes a few seconds, then turns off.

During the full power down, the CPU is off and there is little power consumed and the battery should last for months like this. During sleep, there is much more power consumed and the battery will run down in a week. So if the tablet is not to be used for a while, it is best to do a full power down.

This is where the problem starts. I do a full power down, which i have always done in the past, and after some time later like maybe 48 hours or so, the table is seen with it's screen fully lit up and running! No buttons pressed ever.

At first i thought maybe i bumped it and the power button got hit and so that is how it turned on and i didnt realize it. But recently i built a specially designed case that would house the tablet in such a way that the button could not be depressed even if the case was bumped or rattled or even dropped. That was easily done by using plastic tabs that stick out in places where the power button is not located so that if the tablet slides to the right the case itself will hit the tabs and therefore the button can not be depressed. I tested it several times in many different positions to make sure the button could not get pressed, and it is very very clear that it can not be pressed without removing the entire tablet from the case. The case has a snap shut lid that can not open without considerable force.

Also, the case is made of semi clear plastic so it is easy to see if the screen is lit up. If it is lit up, the device is turned on.

So what is happening is the device is turning on by itself now. There's no way anymore that the button can get pressed, so it has to be being turned on by an external signal or by some internal self generated signal. There's no other possibility now with the new case in effect.

So the question is, does anyone know what might cause this or did they ever see this before?

I have read that there is anther device that 'turns itself on' but i think that is when it is in 'sleep' mode not fully powered down, and that one is a Toshiba. The one i have is an iView Tablet.

Any ideas?

 

[kinarfi]

maybe it's like a computer and you can tell it what to allow it to use to wake up

 

[KeepItSimpleStupid]

Any Network settings like "Wake on LAN"?

 

[MrAl]

Hi guys,

Thanks for the replies here.

Well, there is nothing else connected to it like a keyboard, Lan, monitor, nothing. It's just the tablet itself. Also, i would expect it to be able to wake from sleep mode but not from total power down. The only external communication it can have without anything else plugged into it is WiFi. And that is not only turned off before power down, but i would think power down is supposed to turn it off for good until the users presses the power button for 2 seconds.

So i cant see it waking for any reason like WiFi either because it should be totally powered off. Does that sound right to you too?

This is actually a very big problem because if it turns on it runs the battery down in about 5 hours. You dont know it then because the screen goes dark. When you pick it up to use it two weeks later, it wont turn on until it gets an external charge for several minutes and then the battery is still extremely low.
I normally keep the battery between about 90 percent and 100 percent charged. One time i saw the screen lit up and it was around 25 percent drained already, another time it was 100 percent drained and would not turn on. This last time yesterday (which prompted this thread) it was down to 94 percent down from 96 percent which means it was only on for a little while before i caught it. But if you dont catch it, it can run down to 0 percent and then you cant use it when you need to.

 

[ericgibbs]

hi Al,
Whats the laptop model number/type etc.?

Eric

BTW: I think you may have invoked the wrath of the fictitious electron with your recent posts, its trying to tell you, I really exist.

 

[alec_t]

Also, i would expect it to be able to wake from sleep mode but not from total power down.

I suspect even 'total power down' isn't really total. The 'power on' button has to be sensed somehow and may just wake the cpu from very deep sleep so that the duration of the power button press can be determined.

 

[MrAl]

Hi again,

Eric:
It's an iView 754 TCP

Alec:
Well the power down cycle means you've got to totally reboot the system once you turn back on. I could look into this further, but i tried to cover this in the first post. "Sleep" mode is different and it does not power down, but a full power down means it uses very little power. Not sure electrically how it achieves this, but it should not turn on and run the battery down in any case. In sleep mode it uses more power so the battery drain would be expected, but it should turn off nearly completely during power down and i doubt the processor is running unless it has a sleep mode of it's own like a uC chip where it wakes up every couple seconds to very quickly check key state. So maybe it's detecting an erroneous key state, but this is all guess work.

 

[alec_t]

i doubt the processor is running unless it has a sleep mode of it's own like a uC chip where it wakes up every couple seconds to very quickly check key state.

I suspect its's doing exactly that intermittent key state check. So electrical interference might be mistaken for a key press signal ?

 

[MrAl]

Hi alec,

Yes that's a good guess i think. I dread having to trouble shoot this thing as it's pretty small with components packed together closely. I dont know if i can even get to the switch terminals to measure anything there. I have to do something though because i cant have this thing turning on whenever it feels like it and draining down the battery.

I was thinking maybe i can look for a power "OFF" timer in the software to see if i can get it to turn off automatically after say 10 minutes. If i remember right is has that function somewhere in the software. At least that way if it turns on by itself it will at least automatically go into sleep mode after 10 minutes and save power. I'd still have to check it once a week though to make sure it did not turn on and go to sleep, but at least it wont be dead when i go to turn it on. What a pain.

I wonder if Google can activate it when it thinks it should do so.

I found the setting. I can get it to go to 'sleep' after 1 minute of inactivity. That's still not that great though because if i dont know it turned on and then went to sleep the battery will still run down in a week or two. So three weeks later i would not be able to turn it on without charging. Still a pain.

 

[RCinFLA]

Another possibility if it has a multi-pin connector for docking port is there has accumulated 'crud' creating some degree of leakage across the port pins. The wake up enable on some of these ports only takes a small amount of current to activate them.

Try taking a small brush on the port while holding the unit with the port pointing downward. Then follow it up with a brush dipped in alcohol, again with port pointing downward to minimize any of the alcohol leaking down into unit. Let it dry off and maybe it will behave.

 

[ericgibbs]

There are two ways to "shut it off", one way is to put it into 'sleep' mode, the other way is to do a full power down. In sleep mode, the cpu i think still runs at least now and then, and if you press the power button quickly the unit will turn on completely in less than a second. The other way is to do a full power down. When that is done, to turn it back on you have to push and hold the power button for about 2 seconds, and then it boots up. Booting takes about 10 to 15 seconds.
To do a full power down, you have to press the power button for 2 seconds rather than quickly, and then you get a message on screen that asks if you really want to power down, and you press "OK" to fully power down. It takes a few seconds, then turns off.

hi Al,

I downloaded the user manual, on Page #2, it says hold the Power button down for about 5 Seconds and the Power Off option will be displayed.

Click OK and it will be completely powered down.

Eric

 

[alec_t]

A relative of mine had a similar problem with the radio in his car. That would turn itself on, annoyingly, at random. His solution (until he gave up and replaced the radio) was to pull the fuse. No such option with a tablet though . Looks as though the days of real switches are over; all we get now are 'soft' switches.

@Eric
I get the same power off option with my tablet (and always use it), but still don't believe it completely powers down

 

[MrAl]

RCinFLA:
Thanks, but this does not have that kind of port Has USB that's about it.
It does have WiFi though.

Eric:
Thanks for looking that up. That is just what i have been doing, and i want to stress that if i dont do that but rather just touch the button quickly it does into "sleep" mode, and that does not display a message asking to confirm power down. The message that asks to confirm power down is very visible and impossible to miss. So it is very impossible to mistake sleep mode for power down mode because power down mode requires a second human action, pressing the "OK" button while the sleep mode does not require that.
But what else is interesting is even in "Sleep" mode the screen stays *off* so it conserves power. So even in sleep mode the screen would not be on. This problem involves the screen being on constantly just as if i rebooted by holding the power button in for several seconds. It's quite nutty that this happens.
As i said previously i did find the auto sleep mode which helps a little, but that's not the solution. It should be able to power down and stay powered down.
Yes, the electrons are mad at me because i called them 'fake'. But if they are not nice to me i'll have to start to replace them with holes and see how they like that

Alec:
Yes that's a good point about the 'soft' switch. I hate that. Somebody please give me a 'real' switch for a change. We have to wonder how they are polling that switch now, with the CPU or with some secondary watch dog ic chip that just wakes up briefly to check the state of the switch. Whatever it is it could be making a mistake about the state, but strangely enough it would have to make that mistake for a full 2 or 3 seconds because that is what is really required to turn the tablet back on normally. The button can not be just briefly touched, it has to be pushed in and held for 2 or three seconds before it will start to reboot and come up to full operation with the screen on. If i just briefly press the button, nothing happens. So it has to somehow think that the button had been pressed for a full 2 or more seconds, which is even stranger, because that doesnt seem like noise then.
The tablet is not very old yet either and the switch is not dirty or anything like that.

Other strange things:
I noticed that "Google Services" and "Google Play Store" want to start up every time i reboot. Those two apps start automatically. They slow down the browser quite noticeably too so they have to be turned off before browsing. When i see something like that i just have to wonder if Google isnt interfering with the normal operation of the tablet in other ways too.

 

[alec_t]

Those two apps start automatically.

It seems an increasing trend with all operating systems (or at least with all new computers/tablets with pre-installed software) that, by default, they want to auto-start various apps/services and the apps and/or OS are constantly 'phoning home' to try and update themselves. It can take ages setting user preferences to prevent this happening. This default behaviour may be ok for noobies or for users with unlimited fast broadband, but for more experienced users or those not so lucky with their broadband service it can be infuriating.

 

[MrAl]

Hi again alec,

Well the internet connection is pretty fast, but the tablet itself is only 1GHz single core, which by today's standards is ancient
So i cant have any apps running in the background while surfing or else it appears very very slow to load pages.
I meant to find out more about those Google apps, but i dont need to use the tablet that much it was meant to be used as a backup for online business if the main system went down. I think it can be uninstalled, but then you loose the play store too.

 

[alec_t]

Have you tried a system restore to the OEM software? Might fix the flakiness, but you'd probably lose any apps you've downloaded, and any OS updates.

 

[MrAl]

Hi alec,

Well i dont want to try that option because there are risks involved. That's an idea to keep in mind though, thanks.

 

[Menticol]

I have an idea, but I don't know to which extent you can be implement it. Leave the tablet on a visible place and keep note of the approximate times it turns on. If the times are consistent that means that the software is "intelligently" commanding the turn on. In that case a radical solution like Alec's would be required.

If the turn on times are random I guess there's some dirt on the power button tracks, keeping the button on a "limbo" state were is never fully opened. Well, maybe!

 

[MrAl]

Hi Menticol,

Yes that's an idea. I've also thought about noise reaching the power switch too. If there was interference from another device somewhere it might trigger the watchdog poller to think the switch is depressed. But it is strange that it would have to think it was depressed for a full 2 seconds or so, because that's what it takes to do a cold boot up.

Also, suposedly there is no software running because it is "shut down" just like a PC would be. So it demands more careful analysis to find out the root cause but i havent gotten around to playing with it more yet. I did check it yesterday and it was still completely OFF, so we'll see how it goes. I might have to get the scope out for this one.

Any ideas about a web site turning it on somehow via WiFi, although that should be off too.

 

[MrAl]

Hello again,

This is an update on the progress.

After turning off all the Google apps, the tablet did not turn on by itself now for the past three days. So far it looks like it turned itself on after about two days before this, so i am hopeful that this fix did the trick. I wont take any bets yet though until after another few days or maybe two weeks. But so far it looks like it was turned on by an app that has the ability to take the tablet out of a full power down mode into full operation!

This is just nuts and goes to show what this world has come to. But i'll wait a few more days or a week or two to be sure. But at least now i am keeping a close watch on it so it can not run the dang battery down without me knowing it. What kind of dingbats would allow this to happen.