I've lost my original charger 2 months ago. For about 2 months the Iconia A700 tablet was switched off. And when I got my new original charger, I plugged it in, but the screen began to flicker for some time. I switched it off, then plugged it in again, then after getting charged I turned it on after about 2 hours of charging. The screen was still flickering.
Today I turned my device on, but nothing happened, just vibration at the beginning. Then I connected it to my PC via USB cable and saw the picture. It was still flickering. After plugging it off the usb the screen turned off again. It now shows the picture only through connected charger or usb.
You won't get much help here, I know the login page promises that theses forums connect you to "product experts and users just like you" but the product experts are scarce as hen's teeth ( or non-existant)
But here's your problem.
If this was a Microsoft Windows PC (or just about any PC really) I'd first update the graphic card's drivers.
or roll them back to a previous known good version.
If this didn't work I'd either go for an Operating System reinstall or I'd start suspecting a hardware failure.
Acer won't give you a copy of the Android operating system (that they got for free - Android is open source), it's their view, wrongly, that a factory reset is the same as a reinstallation.
All the reset does is to remove all your private details, if the software is corrupted it will remain corrupted.
so if you're out of warranty you're pretty well up the creek, Acer will ask you to send the tablet back to them, this might take quite some time and if it's a hardware issue the cost of repair might make it cheaper to buy another tablet.
Good luck though, try a reset, it might work
Try emailing Acer this will take a few weeks to get any sensible dialogue from them.
Look on eBay for a used ASUS - they have great service staff
The problem isn't in the PC as I've installed everything needed to make it work with the tablet.
The PC still can't recognize it. Can it be because once I charged the tablet via a non-original charger which had the same characteristics (12V, 1.5A, 18W) before my original charger arrived? Now the display is turned on only if the tablet is connected to PC or to the charger and it flickers if the battery is under 90%.
Is it because of the USB plug or maybe the battery? What would you think?
I can't answer all of the questions but related to the charger .. there is one other characteristic .. the polarity. If the polarity is different there ccould be a problem. When you had it plugged in did the power indicator function as with the original? If it did then all should be okay. If it did not then it may have damaged the battery or charging system.
A trick that has cured a multitude of problems is to pull the battery if possible and press power switch for a minute. If you can't pull the battery let it run down till dead, press and hold the power switch, charge it and try it.
You might try a return to factory in settings. You will loose all data however.
If the polarity is wrong it will totally discharge and attempt to charge the wrong way in some cases. There may be safety features in the unit to protect from that also so I don't know whether there was damage or not. Most current stuff should have safety features.