Nexus 7 turned off on its own, won't turn on - Nexus 7 General

Hi,
My 2 week old Nexus 7 shut off while charging - I didn't even notice! - and it won't turn back on, whether I connect it to AC power using its charger and cable or whether I connect it to my computer.
I tried holding down the power button and the power button + volume buttons, didn't work. What can I do?

I tried the volume down + power trick again and it worked. Weird. Is this a known problem? Running Android 4.2.2 here.

tehpea said:
Weird. Is this a known problem? Running Android 4.2.2 here.
Click to expand...
Click to collapse
There are a variety of different problems revolving around battery issues. What percent of N7 owners experience them is unknown, but a variety of different syndromes have been reported in these forums:
a) tablet mysteriously won't start (& battery is believed to be charged)
b) tablet shuts down spontaneously (battery charge < 40%, but > warning level ~ 14-16%)
c) % charge reading doesn't change / won't go to 100% on charger
d) attempt to start tablet results in "static screen" / "sparkling screen"
e) charge rate is extremely slow
Every time (d) is reported, it seems to be a case of a discharged battery, and afaik always resolves by putting the tab on the charger for a while.
All the other syndromes don't uniformly resolve with a single fix, but a lot of folks have reported finding (when they pop the back cover off) that the battery terminal plug was loose, or that unplugging their battery for a few minutes resolved their problems.
There are two chips in the N7 that relate to battery issues. One is the TI "fuel gauge" chip. It does nothing but observe the battery voltage and current, and use that to produce a "% charge" value. This is exactly the value reported by the OS. (It literally is read straight from hardware, there is no "battery calibration" software in the OS involved). This chip is directly connected across the battery terminals, and is essentially on 100% of the time - even when the tablet is turned off. The only way to "reset" it is to unplug the battery from the tablet for a little while.
The second is a chip made by SMB that understands USB device detection protocols, and it determines the battery charging current - both when the tablet is on and also when it is turned "off".
Both of those chips appear to be "stateful", and also have modes that are supposed to deal with dead batteries (not just low voltage, but seriously low voltage).
My suspicion is that some of the above problems are caused by a loose/intermittent battery connector plugs. A voltage drop-out of a few microseconds might not cause the tablet to crash (current is drawn from power-supply capacitors during the dropout), but can seriously screw up the statefulness of either the charging chip or the fuel gauge chip (the voltage droops a little, but the sense current goes nuts.)
So anyway, keep an eye on it and have a look at the numerous "battery problem" threads on here. If you continue to have problems, maybe pop off the back and see if you have a loose connector. Other than that - send the tablet back under a RMA.

Consider checking this sticky.
You'll probably find your answer.
-bk

Just exchange it!
Unless its been fine since. Cause occasionally, poop happens.
Sent from my cell phone telephone....

Related

Red Light of Death : Fix and theories

Without knowing what it was, I encountered the RLOD on my phone after leaving it on USB overnight. After reading the first two or three pages of two different threads I tried the little lucky "fixes" and found that none of them worked.
I have a backup phone and need my phone for work, so I put my SIM in that phone only to find it was dead. Went to my local AT&T store and they said the SIM is fried. They replaced the SIM and everything is working now.
I replaced the battery in my TyTN and now I'm recharging my original battery. The phone works without problems, or heating up, or shortened battery life.
So here is my theory:
The phone has a similar monitor as the offgrid solar system does. It's job is two-fold: don't let the battery overcharge -and- don't let the battery every discharge to 0.
I suspect that most problems may happen when the phone is connected to a laptop or desktop computer via the USB port and left on when the computer goes to sleep. At this point, the scenario is similar to a monitor on an offgrid solar home. The monitor decides when to pull from the batteries and when to fire up a generator. But if the monitor is set incorrectly, it constantly flicks between charge/generator and the end result is a huge draw on the batteries (rather than a charge going into the battery).
Now with the laptop asleep the trickle charge is way lower than normal. Activity on the phone may also actually flick the laptop in and out of sleep mode. The basic end result is the phone starts the same type of draw between battery and trickle charge, causing a higher than normal draw on batteries, and finally it heats up the chip on the SIM and fries it either partially or completely.
If you have "resuscitated" your phone, but still have problems, simply replacing the SIM should fix it. If you get the RLOD I'd say get the SIM replaced as it is fried. Once you get the SIM and any SDHC card out, very tentatively try to recharge the old battery on the wall charger. (In other words, don't take your hand off the charger when you plug it into the wall) If you get a yellow light, breath easy. If you get the red light, UNPLUG IMMEDIATELY and throw that battery away!
My research on offgrid solar has been going on for almost a year and I began this theory when I noticed a few things:
1) I saw posts from people with not just HTC phones getting a red light.
2) I saw a few posts where people mentioned they used the USB overnight.
3) I have seen firsthand what the constant toggling can do to a 24V 1500 kilowatt hour battery system and the heat it generates.
Except...
There is no USB power when a laptop is shut down except for a few newer models which are designed intentionally to do so. And USB activity does not wake the laptop, particularly not "in and out" of sleep mode. If it does, your laptop has problems.
Final point.. Hasn't it been ground in to use the supplied charger? Most people who report failures admit they were using third-party chargers.
That said, a USB cable should be a more reliable charge source than a cheap AC charger due to the fact that a laptop has to have clean power itself and cheap AC chargers can fail in many fashions and often result in excessive DC voltage or AC voltage winding up in the source.

Another brick in the Wall... :-( Needing help with Wizard

Shortly: I flashed a new rom (not so new... Mameli 2.0 with WM6.1) and the upgrade process stuck on 99%, computer saying "All Done"
No so... trying to reboot the Wizard gets up the bootloader screen... no problem, will you say BUT... I was in a hurry so I leave the USB cable connected and go away for a few hours (I suppose the USB cable may keep powered the device but now I guess no... )
So, when I came back, the Wizard was turned off.
First try was soft resetting the device with no success: screen remains black.
Then I try to connect the power supply and nothing happened...
Then I pull off the battery and keep it off for a few seconds... I was googling with the device in this state when the bootloader screen pops up for not more then 15 seconds then blank again...
No way to enter bootloader mode or to hard reset the device...
I suppose the battery goes almost flat... and I've not a cradle... is there any way to charge the battery? or a way to build up a cradle-substitute?
May be the issue due to battery flat?
Thanks, Pino
Try plugging in to the original charger, not a USB cable, with the power off.
After about a minute you should see the orange LED turn on.
At least that has worked for me when my battery has been dead.
Nothing... It was already done... I suppose the charging doesn't happen if the OS didn't load... even if I read about some stating that if the charger supplies 1.0A the charge happens...
Now I'm trying to charge the battery with "alternatives" methods...
Thank you for your interest
and so?!?!?
So much lurking... noone writing?
Ideas welcome....
I've done something similar to this too, i.e., where battery gets so low that phone cannot start charging cycle.
Here is what I have done. Take note on the battery of the positive and negative terminals (clearly marked on battery). Use a regular 9V battery and some wire (or 9V connector) and connect the 9V to the phone battery (+ to + and - to -). Allow the phone battery to recharge some from the 9V. I suggest connecting for about 1 minute or so and then disconnecting again for 1 minute or so, and repeat this cycle a dozen times or (or more) using this 50% duty cycle charging. (not sure about charging current, nor heating of battery and don't want to overheat or damage the phone battery).
After giving the phone battery some (re)charging, then try plugging phone in to see if charging cycle comes on. (try first without trying to turn on the phone. If no response then try turning phone on while plugged in to USB). Generally makes no difference whether using USB plugged into computer, original charger or after market, ... phone does not, nor cannot discriminate between different 5V 'USB' sources.
If this doesn't work then the next step is to carefully touch the 9 V to the battery while in the phone and connected to USB (and to play this safe use charger, and not computer USB ... don't want to risk damage to computer). I would only try this if you feel extremely comfortable with electronics and voltages (albeit this is very low voltage) and as a last resort. KEEP IN MIND YOU WILL BE DOING THIS AT YOUR OWN RISK, and I don't want to be blamed for anything that may go wrong with the phone or otherwise by you trying this. This has worked for me on several occassions, but I am an engineer who has experimented with electronic ciruits off and on for 16 + years and so feel comfortable doing stuff like this. (again remember + to + and - to -, battery to battery).
Good Luck
First of all... Thanks for replying...
The problem isn't due to battery too much empty (it's a frequent issue, with mobile phones too...)
I suppose the Wizard needs be correctly initialized to start charging the battery and mine was in bootloader mode.
Sometimes I am able to power up the system for a little while and the bootloader screen appears but the battery doesn't charges so I cannot disconnect the power supply... this is why I suppose I'd get better times if I got a cradle.
Now I'm trying to arrange a flying connection between the battery and my kaiser's desktop charger to give the battery a bit of charge and verify my ipotesys (uh-oh... it's correctly spelled? sorry for my bad english....)
OK, wish me luck
stay tuned...
OK, no more bricked
The issue, as I supposed, was due to a flat battery!!!
I tried unsuccessfully to charge it back using the external charger for my Kaiser, probably the unsuccess was due to difficult to obtain a stable contact between charger pins and battery leads...
After that I remembered I had another battery. It wasn't used for a bit of months (I use the wizard just as backup, when the Kaiser is out of order) but luckily I stored it full charged so the battery was able to make my wizard power up (strange thing, I needed to keep the power button pressed as the device powers down as soon as I release the button!!!)
I tried to update the rom again but it failed at 99% so now I reverted to an old rom but the device is still alive...
Maybe I'll try again the update but not before having fully charged both batteries
See You and thanks to everyone tried to help...
Pino

[Q] Plugging in charger has no/almost no effect on current flowing through battery

I'm having a problem charging my _new_ Nexus One. In two words - doesn't charge. Tried two batteries and two wall chargers + USB; same result - it charges VERY slowly when the phone is off - like, 1% per hour, and not-fast-enough-to-stay-alive when the phone is on.
So I've been googling for quite a while today, read several dozen threads and it seems that the issue is rather popular. However, there are a few problems:
a) No solution was advised
b) The ones advised didn't work
I've read that I'd better measure the current that's going through my battery and if it's too small, then I have a problem. I've installed an app - Battery Monitor Widget it's called, I think, and saw what's happening. I didn't know what they meant by "small" current, but my case was easy: the current is NEGATIVE even when "charging". In fact, the app doesn't see the difference between an unplugged current and plugged current. This isn't the problem with the app - reversing mA only helps with the app, but all other applications also show that the batter is draining. Note that the LED is ON, that is, the device does detect that the charger is plugged in, it even heats up like usually (I've had nexus one before).
So I thought that was a software problem with 2.3.6 kernel, so I've sacrificed my warranty (the seller p***ed me off - even if the phone turns out to be defective, I'm not bothering to send it back). I've installed Cyanogenmod 7.1 - kernel 2.3.7, but the problem persists.
So I really have no idea what may be causing this or what the fix might be.
Any ideas?

Xperia SP wont respond (no flashing problem or root problem)

Hello my Xperia Sp just run out of battery and shut down.I pluged it in saw the sony logo and when i tried to turn it on it would not respond.
The only thing it did was kept the red light on (indicating charging).I tried pressing the off button for over 30 seconds with no results. Not it is stuck and i cant do anything about that.
Help please.
Nevermind the problem got fixed by itself.
The battery (about 2 % run out and the phone kinda reseted itself.It opened just fine.
So if anyone else gets this problem just let your battery drain itself.
jackaros said:
Hello my Xperia Sp just run out of battery and shut down.I pluged it in saw the sony logo and when i tried to turn it on it would not respond.
The only thing it did was kept the red light on (indicating charging).I tried pressing the off button for over 30 seconds with no results. Not it is stuck and i cant do anything about that.
Help please.
Click to expand...
Click to collapse
Just to confirm you plugged it into a mains supply? USB from your computer to phone charging is not enough to kick start a totally dead battery.
If you have plugged it in to a wall socket and it still doesn't work, give it some time.
I think the battery and the phone's software combine to stop the phone operating at unsafe voltages, the safe operating range for a standard lithium ion batteries is 3.2-4.2 volts (though android may be different). They spend most of their time at 3.7 volts though and this is why they are described as such when you buy them separately.
If, for some reason your phone's software thinks your battery is at 3.1 volts, it won't do anything until it thinks it's at 3.2. Similarly if a protected battery is taken below 3.2 volts it won't provide any power until it hits its minimum voltage. In theory your phone should have cut out before the protection cut in, but bad stuff happens to good people.
Sometimes a protected battery gets drained so much that the tiny flow of electricty required to power the protection circuit stops and as the ultimate failsafe, protected batteries stop working when this circuit is not functioning.
(I'm talking about standard batteries here, not necessarily phone ones)
Sometimes cheap basic chargers won't be able to get such batteries working, but better chargers are able to send tiny trickles to a battery to start the protection circuit and make such batteries charge again. I'd be very surprised if android didn't take this into account and have some way of ensuring over-discharged batteries with a tripped protection circuit can be charged. That said I'm not sure whether the protection is all software on mobile phones?
Like I say give it some time - getting that first .1 of a volt can take a while when the battery is totally flat. If it hasn't changed after at least 2 hours then I'd worry.
Parkside said:
Just to confirm you plugged it into a mains supply? USB from your computer to phone charging is not enough to kick start a totally dead battery.
If you have plugged it in to a wall socket and it still doesn't work, give it some time.
I think the battery and the phone's software combine to stop the phone operating at unsafe voltages, the safe operating range for a standard lithium ion batteries is 3.2-4.2 volts (though android may be different). They spend most of their time at 3.7 volts though and this is why they are described as such when you buy them separately.
If, for some reason your phone's software thinks your battery is at 3.1 volts, it won't do anything until it thinks it's at 3.2. Similarly if a protected battery is taken below 3.2 volts it won't provide any power until it hits its minimum voltage. In theory your phone should have cut out before the protection cut in, but bad stuff happens to good people.
Sometimes a protected battery gets drained so much that the tiny flow of electricty required to power the protection circuit stops and as the ultimate failsafe, protected batteries stop working when this circuit is not functioning.
(I'm talking about standard batteries here, not necessarily phone ones)
Sometimes cheap basic chargers won't be able to get such batteries working, but better chargers are able to send tiny trickles to a battery to start the protection circuit and make such batteries charge again. I'd be very surprised if android didn't take this into account and have some way of ensuring over-discharged batteries with a tripped protection circuit can be charged. That said I'm not sure whether the protection is all software on mobile phones?
Like I say give it some time - getting that first .1 of a volt can take a while when the battery is totally flat. If it hasn't changed after at least 2 hours then I'd worry.
Click to expand...
Click to collapse
The phone was pluged in the wall socket.After this i tried to turn it on (while pluged) nothing happened so i unpluged it to press the off button (i upluged it because i could not reach the button because i had the case on) but the red light ( at the bottom of the device indicating charging) did not turn of.So i tried to reset the device by pressing the off button but i waited for almost 30 seconds (while pressing it) and nothing ... not even a vibration.So i left the phone away with the light stick on till the 1 % left was drained and the phone shut down due to lack of power.
So then i pluged it back in to the wall socket and it started charging again and so i turned the device on.This time it responed and opened up .Now nothing is wrong
It happened again.... i dont know the problem but the solution was the same...
jackaros said:
The phone was pluged in the wall socket.After this i tried to turn it on (while pluged) nothing happened so i unpluged it to press the off button (i upluged it because i could not reach the button because i had the case on) but the red light ( at the bottom of the device indicating charging) did not turn of.So i tried to reset the device by pressing the off button but i waited for almost 30 seconds (while pressing it) and nothing ... not even a vibration.So i left the phone away with the light stick on till the 1 % left was drained and the phone shut down due to lack of power.
So then i pluged it back in to the wall socket and it started charging again and so i turned the device on.This time it responed and opened up .Now nothing is wrong
Click to expand...
Click to collapse
You left the phone in the charger to drain or not? If i put the charger off then red light isn't opened..
Also, how many hours did you wait?
billaras481 said:
You left the phone in the charger to drain or not? If i put the charger off then red light isn't opened..
Also, how many hours did you wait?
Click to expand...
Click to collapse
It took about half an hour because of the battery level being low.
Guys im having the same problem.. anyone who can help will be appreciated.

Teclast x98 air The still ongoing problems (and an ongoing hardware investigation)

So... like most of you, i have at least one problem with my teclast x98 air tablet, version C9J8, running only windows (8.1 pro/10 preview).
At this time i've constantly encountered the following problems:
- not turning on after being shut down. Pressing the power button doesn't do nothing. Sometimes it does this while charging, at the end of the charge, othertimes it... simply won't power on.
- huge battery drain in stand by. I've flashed ALL (yes... all) dual boot/single boot air/air 2 BIOS files i could get, in all versions. If it's got a .bin extension... yes, i've flashed that too. No change AT ALL!
- huge batterty drain... when powered off !?!?! Yes, that's the next level of awsomeness. You know your tablet is special when it sometimes discharges faster when turned off compared with it turned on. (@XDA, guys .. can you please add some facepalm smiley/emoji.. i wanted to use it about 30 times since i got this tablet)
- sudden shutdowns. Like when you use your tablet it simply dies in your hands with no apparent reason.
- battery meter stuck at 7% and only 1 cell reported. NOT fixed by the methods already known (flashing BIOS and letting it discharge then recharge with tablet turned off).
So.. i'm pissed off. I've disassembled the damn thing in search for some answers. I'll by posting some photos with the guts of this thing (c9j8 version).
First of all, I wanted to check the power draw directly from the battery, so i've desoldered the positive wire from the battery and inserted an amps meter to check the current flow.
For example, the stock charger will supply around 1.5-1.9 amps to the battery when charging (tablet off). For comparison a small 5V 1A, samsung charger supplied 1.1 amps in the same setup. Some other interesting facts, when on and booted to windows - the tablet draws about 1.1-2.2 amps (mostly depending on screen brigtness and cpu load). That's a total of 4-11 watts. If you lower the brigtness from full to low (bottom third of the slider) you effectively half the power consumption. As usual the display consumes more then 50% of the total power being drawn. Those who complain about huge power drain on standby will be surprised to know that the tablet draws 0.3-0.8 amps (it fluctuates) in standby. That’s HUGE. It should be 0.03-0.05 amps at MAXIMUM. 0.3 amps multiplied to a 3.8volts cell is 1.14Watts draw per hour at minimum in my case.
Leaving that aside, let's return to the above problems. The battery is connected to the motherboard by using a 3 wire connection (positive, ground and data bus/i2c or similar). The motherboard itself doesn't feature ANY protection/power management chip aside from a single ROHM controller located under a metal shield. Even if some data is passed between the battery and motherboard, you can simply decouple the battery and power the tablet with regular 18650 lithium cells or 3 AA alkaline batteries in series. The tablet is stupid enough not to notice any difference.
Let's go more deep in the start-up sequence.
When you press the power button, a half a second 500mA ramping to 800mA load is registered. The power management chip measures the voltage drop under that load and if it deems it to be "acceptable" it passes power to the rest of the motherboard. BIOS/firmware takes over from there but does a measurement of its own. If it results in an "ok" the boot sequence can the follow. If not, the BIOS would then power off the tablet. Here lies the first problem. The power management chip and BIOS thresholds for a "low voltage" battery are different. Very different. The chip itself considers the battery voltage to be ok if it's above about 3.45-3.5 volts and not dropping lower then 3.3v under a 500-800mA load. The BIOS/firmware (or whatever software part does this) won't accept a measurement below 3.65v. volts. So, when you pass the BIOS stage and boot to windows, the data you get when checking your battery comes from the power management chip. If you fully discharge the battery in windows (down to 2-3% or similar) and you are able to shutdown the tablet by yourself (it doesn’t cut power by itself) you could find that it cannot power back again because even if the power management ic gives the go ahead, the bios/firmware side refuses to go any further. The battery must be charged for some time before the bios will allow for booting.
The problem is that both power management IC and BIOS readings should be taken in same way and be of similar value. They are not. It’s not that Teclast couldn’t do this, but for whatever reason they decided to write the BIOS in that way. The 7% problem could originate in the fact that a what the BIOS considers a dead battery (0%) is actually charged to a degree and is different from 0% measured at the power management chip level. Overall the power readings are inconsistent in both measurement and reporting. It doesn’t seem to be a hardware problem.
Another problem is how „dumb” is the battery management hardware. In any modern portable computer (laptops, tablets, even phones – excluding some chinese products) you cannot simply disconect the data bus from the battery and simply feed some random 3-4 volts to power the thing. It’s like you would remove the battery from your laptop, check the label on it for the voltage rating and stick a bunch of wires on the contacts (2 of them) and expect the thing to boot. It won’t. Firstly because IT’S NOT SAFE. The battery or motherboard can’t report one to another if a fault is occuring and can’t accurately measure voltage/current consumption.
Yet another problem is that the same power circuitry does not compensate for large voltage/current swings. A simple experiment for you folks to try. Get a aa battery (a battery in general) measure it’s voltage as it’s sitting still then connect a small lightbulb/motor/led/whatever load runs on that battery and measure the voltage WHILE the battery suplies current to the load. You will find a voltage drop at the battery level. It’s normal, is how these things run. A complex electronic device must take that into account in it’s design. At idle/browsing web/viewing picture, the tablet draws about 1.1 amps from a battery that’s registering 3.87volts (at that test’s time in my case). Running a benchmark/video game produced a series of spikes to 2 – 2.1 amps and an aditional voltage drop to around 3.61 volts. Remember that some power rails require exact voltages (cpu core, main bus, 5volt usb bus etc). The power circuitry must provide those exact voltages regarding the input voltage swing. Noup... and that’s the main problem untill now. THEY DONT! I was shocked to see how the chinese engineers are pushing it right on the edge. If you desolder one battery pin and insert an ampere meter in series, that’s enough to induce the little voltage drop needed for the tablet to freeze under load or shut down alltogether. The ampere meter leads were rated to withstand 10 amps under load – and they do, yet the simple fact you inserted a piece of wire along the track is enough to disturb an already delicate balance. The thing is only barely capable of whitstanding it’s own battery voltage swing. In my opinion you can try to reduce the load by disabling turbo modes on cpu/gpu or whatever (and teclast tried with some bios/models of the x98 air) but you cannot fix this by firmware. It’s just bad hardware design. They cut costs on the power management side.
Those are my finds untill now. I’m thinking of adding some capacitance over the power rails to take the load over from the batteries when a large amount of current is drawn (spikes that occur under load). Other then that, there is not much to do about this.
Even so, i don’t know why the tablet still draws power while turned off. I wasn’t able to make it do that while measuring. Aditionally i don’t know why only one cell is reported in windows. More tests are required.
This is still an ongoing "project". Some of my conclusion could be wrong at this stage. Like i've said it's still a work in progress. It would be quite a thing if anyone with some knoledge about the BIOS code (or how it runs on this tablet) could step in and direct me to the right hardware to examine.
here are some photos with the guts of this tablet
As you can see, the C9J8 at least has some metal shield above the cpu area and some crappy thermal compound over it. Some older models lacked the metal shield.
Next we have the battery wires and their link to the motherboard. As you can see, left to the 3 wires there are 4 brown devices, mounted in parallel. Those are capacitors. Like i've said above I'm thinking of adding some aditional capacitance to further help the motherboard compensate for the voltage drops registered on high load scenarios. The chinese guys thought of that, added the 4 caps but deemed them enough. Noup, that's just barely doing it. In fact the whole design is made to a price point, that's to be expected.
For easier probing, I've disconnected the red positive wire, and added a piece of wire of my own, one end to the battery red wire the other to it's coresponding pad on the motherboard. At the end of my wire, i'm probing in series with an ampere meter.
And for the sake of it, here's a photo with the registered power consumption with the tablet on. 1.11 amps x 3.8 volts = 4.21W total power being drawn. Actually that's pretty good. I remember the days i was probing a htc hd2 for some cpu related problems. While doing a benchmark at full brightness that device draw a maximum of 5.5 W. Due to the recent advancements, now we see a tablet drawing only 4.2W (admited, it's not on full load, but the screen is also much larger).
Anyway let's get back to our problems.
1. The high power drain when the tablet was off can be solved in the same way as fixing the reported battery capacity. Like previous guides made, you need to fully discharge the battery and then charge for 8 hours with the tablet OFF (don't turn it on). I had to do this 2 times to get the thing to work.
2. 7% battery and 1 cell reported. Like i've said in my first post, i've tried to let the battery discharge and then recharge while turned off. It never work. However, after desoldering the battery wires from the motherboard and then soldering them back (power was cut off from the motherboard during that time) now after my first attempt to discharge/recharge the battery, the capacity and number of cells are reported correctly for the first time since i've had this tablet. I now have to discharge the tablet again to see if it will get stuck at 7% again but at least i get the capacity reported like it should.
2. The shutdown/freeze under load. This thing ocured to me several times in the past but for whatever reason the tablet doesn't do that anymore. Arghhh.... Anyway, if anyone has this problem and knows how to reproduce it in windows (i'm only running windows now) please do tell me in order to test some solutions to it. My first try is to add some capacitors over the main power rail. If this will work, i'll then design a capacitance multiplier circuit using some transistors since there is not enough space in the tablet to simply add capacitors.
3. High standby drain. In my best scenario, the tablet draws 0.3 to 0.5 amps in standby and that's huge. I've tried disconnecting various devices on the motherboard but all that power goes into the cpu area. It has to do with the cpu core voltage and stand by states. The cpu is simply not sleeping deep enough. However that should be fixable with a bios update if teclast should decide to bother with that. One problem though, it seems not all tablets have this problem. But since it's located in the cpu area, if it should be a hardware fault there is no practical diy fix for that.
Just to confirm, you have tried the 2.02 BIOS that was released with the Lollipop beta a few weeks ago? Several people have reported that this BIOS solved the Windows standby battery issues. I've avoided flashing it myself because many people have also bricked their tablets.
Edited post..
I did tried that, no change. I'm close to fixing my particular problem. I'm now at about 1% per hour.
I'll keep testing meanwhile.
this seems allot like my issues with a C5J6, mostly unstable while charging or shortly after charging, also restart/shutdown is a hit and miss, most of the times I need to hold the power button for 10 seconds after I do reboot/shutdown and start the tablet again.
I'm trying to contact the seller (got it from banggood) but they want a video, should not be that hard but I dunno what they can do about obvious design flaws.
Do you think you can ever get the tablet stable yourself? (I'm not completely sure it's part Windows issues or not)
btw, I only use Windows as I was not interested in another android tablet.
I also just picked up a X98 Air 3G from GearBest, it's the C5J6 version. I just ran into the battery charge stuck at 7% in windows. I'm going to try clearing hibernation data, turning off hibernate while low (powercfg -setdcvalueindex SCHEME_CURRENT SUB_BATTERY BATACTIONCRIT 0) and then fully draining (manual) and letting it charge while off overnight.
I'm very interested in what you have been finding, I would be more than willing to help out if you need any assistance. I have a mutli-meter, soldering iron and a desire to get this thing working like it should. It bugs the hell out of me that it has these silly problems. My Bios version is 5.6.5 with a BIOS build date of 1-16-2015.
Could this have something to do with the Intel Power Managment drivers? Does this 7% problem still continue under Android? I suppose I need to do more testing myself.
HWINFO shows 14432 Designed Capacity (half) current capacity is 1007 mWh (7.0%) current voltage 3.784 V
It's been working fine under Windows for the last week, I dont really use Android much though I will likely try RemixOS sometime soon. I was considering blowing out all the partitions (BTW is there a map of all the partitions and their functions/contents?) and going with straight Windows 10 Pro when its full final version is out.
Is there a list of all hardware revisions and their release date and changes/logs? C5JG,C9J8, wtc......) the naming convention seems to have no real correlation to revision date huh?
PS: I also have been getting forced hibernation under heavy load/heat. I wonder if switching to another version of Windows will change anything? Anyone have the 7% issue and shutdowns under Win7?
Hello liquidmass. The 7% problem happens for me in both windows and android. I haven't figured out what to blame but the hardware side "knows" how to measure the actual charge level, it's just that the reporting part is all wrong or the software is poorly written (BIOS, mostly).
Funny though, all my initial problems seem to have vanished. I cannot figure out why since i can't make the tablet to do those bugs again. The single most probable thing it could have made any difference was the fact that i desoldered the battery wires and short circuited the pads on the motherboard (all 3 of them together) during some initial testing. Since I cannot make the tablet to shutdown under load I can't test a capacitance multiplier circuit over the power rail in order to check for improvements. The damn thing just works now.
Yet, the battery gauge still is broken and since i don't know the software side of these things i cannot figure out why. I can let it discharge completely and it would work fine for some time but it will occur again and so i would have to do it again and so on. I guess i can live with that...
motoi_bogdan said:
Hello liquidmass. The 7% problem happens for me in both windows and android. I haven't figured out what to blame but the hardware side "knows" how to measure the actual charge level, it's just that the reporting part is all wrong or the software is poorly written (BIOS, mostly).
Funny though, all my initial problems seem to have vanished. I cannot figure out why since i can't make the tablet to do those bugs again. The single most probable thing it could have made any difference was the fact that i desoldered the battery wires and short circuited the pads on the motherboard (all 3 of them together) during some initial testing. Since I cannot make the tablet to shutdown under load I can't test a capacitance multiplier circuit over the power rail in order to check for improvements. The damn thing just works now.
Yet, the battery gauge still is broken and since i don't know the software side of these things i cannot figure out why. I can let it discharge completely and it would work fine for some time but it will occur again and so i would have to do it again and so on. I guess i can live with that...
Click to expand...
Click to collapse
I'm trying to figure out the 7% bug as well but I don't think it has anything to do with software. I might try and open it up to de-solder the battery wires and short the mainboard pins (if anyone else does this, make sure you do disconnect the battery and don't short the wires of the battery!!)
The shutdown under load might be my issues as well, but the most annoying thing probably is that reboot or shutdown don't work most of the time, it will just hang in a state that requires me to press the power button for 10 seconds and start it up again (with shutdown this isn't always obvious until you try and turn it on again)
I kinda hope things get a bit more stable with windows 10, else it's quite an expensive paperweight to be honest.
Hello,
I have several months a X98 Air 3G with id: C5J6. After two weeks I try install thunderbird and windows 10 collapse. I send several mails at Teclast with very little result. Such things as brushing in the language Chinese. After a while I try to reinstall windows via the UBS. After that my tablet has a black screen. I try to send the tablet back to china but that’s no option. I have experience that its never come back. With the USB flasher CH341A and a flash cable I flash the WINBOND 25Q64FW on board after disconnecting the battery. When I read it is flashed. So far so good? After loading with 5 volt and connecting the battery my tablet stays black. Now I put it in the box and put it far a way and buy something else. Never again in china.
My x98 is been stuck at 0% battery it wont turn on or charge...
I've disassembled the tablet and charged the battery externally, still not working. Any sugestion?
Hello, we have encountered similar problems with the Teclast Air III not turning on. Did you conclude anything?
Larterptx said:
My x98 is been stuck at 0% battery it wont turn on or charge...
I've disassembled the tablet and charged the battery externally, still not working. Any sugestion?
Click to expand...
Click to collapse
u should cut the red wire in the battery.. wait 5 minutes to reset then again solder the wire..
I encountered the same problem and above solution worked for me
I turned my tablet off last night and plugged the charger in. The tablet already had maybe 60 or 70 percent charge. This morning it wouldn't turn on or charge. I tried the above and desoldered battery etc but no luck. The charger is putting out 5v. The battery only read 0.05v. And when on charge it reads 0.38v. It's my battery dead and needs replacing it is It another problem.
Same problem not turning on after battery fully drained in win8, please help
The advice I found somewhere to check power management on drivers seems to have stopped power drain in standby (windows 10). in particular Sound controller>realtek I2S Audio Codec>Power management>untick "allow device to wake computer"
Now the thing doesn't drain too badly. Before the rapid drain also lead me to the power on issue which I can now 'solve' by getting a charge in before it drains.
Alos, needs at least 2.1amps charger to fire up after draining.
Still get that uncertain feeling as to whether it will turn on or not!, but the last week or so has been fine.
I can confirm the power drain issues. Our Chinese friends made no effort in stabilizing the power line.
I'm using my AIR 3 as a home automation / wall tablet. Because it was unstable as hell I disconnected the the battery-print from the battery, and connected a laptop charger (4.62a) with buck down converter to it. With some tinkering I made Android believe the battery was 100% full and always charging. This made it much stabler, but still every 2 days, it just dies on me. Keep in mind this is a wall tablet, the screen goes off, only wifi is at full-performance wake-lock. So it's doing absolutely nothing, ice-cold to the touch, and still dies in the middle of the night. It's not logging errors anywhere, so I suspect a hardware problem.
Pondering what to do because the tablet is already flush mounted and I would need a different tablet with the exact screen dimensions.
Absolutely no more Teclast for me...
Has anyone modded the Teclast X98 to work without battery. Plugging a cable directly to the battery connection inside?
I see someone used a laptop charger, but I dont have one. Is it possible to use a regular USB charger?
I just bought a new battery and even with it the drain is absurd. This tablet has become unusuable.
Sadly Teclast is absolute garbage
Dear friends....Be careful with this company....their items is totally un- trustworthy..After sales support is terrible, they dont respond to emails messages etc and generally they dont care about their customers....this is not only my opinion, read the XDA forum about teclast products...Too bad for this company. Try to find what you looking for to another brand.....https://forum.xda-developers.com/x98-air/general/teclast-warning-buy-t3161767
I have air 3g model C5J8, It is working quite well, but with 2.5 A power charger when working with both OS's on it, batery is draining, It means that it is impossible to work with tablet longer than 7-8 hrs even with power charger connected, Is it normal in this model?
I tried using the tablet without battery with a 3.1 amp usb charger, but the Air III powerpeaks are to much for it to handle.
Now with a laptop charger of 4.62 amps, it's mich stabler, but it still dies on me...
Teclast = crap. Don't waste your money on it.

Categories

Resources