Iconia W3-810-27602G03nsw non responsive power button

Diode23

After a full shutdown from the OS the power button does not turn the device back on. 

The device does succesfully charge, showing the orange led light at the power button whilst charging and changing its color to blue when fully charged.

Using the factory rest option with the power button and volume button does not work either. 

We've tried removing any USB device attached as well as removing the SD card. 

Is there any option we could try ? before we open the tablet to see the solder on the power button. 

billsey

First try a forced power off by pressing and holding the power button by itself for 30 seconds. Wait a couple of seconds then try turning it on. If that fails you are likely right in that it's a mechanical problem with the button.

Diode23

billsey said:

First try a forced power off by pressing and holding the power button by itself for 30 seconds. Wait a couple of seconds then try turning it on. If that fails you are likely right in that it's a mechanical problem with the button.

Hi Billsey, 
Thank you for taking the time to write a comment for our issue. 
We've tried the 30 second solution with just the power button as well as a combination with the nearest volume button. However the device did not powered back on. 
The issue is the device not powering on, rather than not / or shutting down. 
Since we do not see the camera its light go on and the battery charging normally we excluded the possibility of a dead screen / battery. 

We'll keep an eye on this topic for some days in hopes someone else is kind enough to comment with any plausible solutions, as you were too. 
Thanks Billsey!

billsey

On the W3-810 there is a separate board that has the power in jack. It also holds the status LED, the battery connector, the home key button and the speaker wires. It's possible that the wiring that connects it to the motherboard has come loose or broken, leaving no way to power the main system up. Are you still in warranty?

Diode23

billsey said:

On the W3-810 there is a separate board that has the power in jack. It also holds the status LED, the battery connector, the home key button and the speaker wires. It's possible that the wiring that connects it to the motherboard has come loose or broken, leaving no way to power the main system up. Are you still in warranty?

Thank you for replying Billsey. Our warrenty expired.

We've opened the tablet and took a picture attached below. 
Using a breadbord cable I've tried making contact between the connector its solder attachments. It did not start up the device however. After doing so I've tried the same approach to numerous transitors on the board it self. The power LED indicator does light up when the charger is plugged in. Strangly enough the battery wants to charge even though it was fully charger before. We're currently leaving it charge for some hours. 

We've also tried the cable approach onto the battery its connector on the board and found out we could manualy let the board think its fully charged, indicating theres power flowing threw the circuit. We've also managed to get the power LED indicator Blinking orange, of which we don't know what it means. We've repeated this approach with an 850mah lipo from a toy of which we know its good.

After doing so we've tried the push button located near the SD card holder, since a user claimed this is a reset function. We're not sure of that, but pushing it does result in the same orange blinking on the power led indicator.

At one time the powerled indicator showed us a red light, which is likely to indacte my breadbord cable was in a very bad place haha. 

We're waiting to see if the powerled indicator shows blue again, since we've excluded a failure from the power button. Also we're under the assumption the screen isn't the failure since the camera its LED light won't show up and we've also make sure the device did not appeared on our network list. 

Image url to imgur showing the opened device
https://imgur.com/cak57cM

billsey

Yeah, I don't see anything obviously wrong in the picture, the two red and two black wires should be power and ground off the charger. I don't know what the blue wire is for, I surmise it's a return sense wire telling the charger to back off once a full charge is done. The ferrite bead in the middle of the cable is just to reduce EMI radiation and should affect the charger current. Try disconnecting the cable and ohm out each end, it should have very little resistance through it and obviously not cross connect. Do the same with the wire between the battery and motherboard and if all else fails pull the motherboard to inspect the solder joints for both of those power connectors. Something in that circuit isn't getting to the logic side of the motherboard...

Diode23

Hey Billsey, again thanks for taking some time to look into our issue. 

Today I've brought a multimeter to test some of the circuit its part. Its power button changes the voltage running threw, so its safe to assume its still working. 

The battery did managed to charge up again although it took some hours todo, over 6 hours.
The voltages from both red wires were in the expected 4.2 range, so again here I'm guessing this battery is functioning. It should at least be enough to show the booting screen. 
the blue white yellow and green wires all have a lower voltage running threw them of 3.2v. 

After hunting the net a bit for these wires I;m guessing either the white or blue wire is for an NTC resitor. So indeed a thermal sensor preventing the battery from over charging. I've read that these NTC commonly opererate with a resistance of 10KOhm so this weekend I'll try to see if I can find one of those at home. Today I've tried an 7Kohm ones, since I had no resistors to use. 

The charger its voltage seems to be correct. 

If all fails, I'll try to check the monitor / touchscreen by trying to connect it to an raspberry pi , no idea if that's even possible, would be nice ifso to salvage it. 

What the yellow and green wire are is a mystery for me, it might be a clock or just the secundairy NTC for the secondairy cell in the battery. 

We'd like to thank you for the time you've spend on helping us with the details you wrote us about. Should we like the all the post in your benefit??? cause of your help you've given ?

billsey

Sure, it's always nice to have likes and solutions, but not needed really. I do this because I enjoy it not because of the numbers.