Hi,
On 17-10-15 15:13, Benjamin Henrion wrote:
On Fri, Oct 16, 2015 at 8:52 AM, Hans de Goede <hdego...@redhat.com> wrote:
Hi,
On 15-10-15 16:58, Benjamin Henrion wrote:
Hi,
I got Q88 tablet with a broken screen from the flea market for 4EUR.
Soldered the pins on the back for the serial port, got the console
working by powering the device from the USB port AND from the 5V DC
with a Nokia plug:
Hi I've bought a couple of q8 tablets the same way :)
So you say pins on the back, so I assume that this is an A13 device ?
Yes, there is some speaker glued on the main A13 chip.
A number of things:
1) Try building the latest upstream u-botot (from git master) with
the q8_a13_tablet_defconfig, and write that to an sdcard using:
sudo dd if=u-boot-sunxi-with-spl.bin of=/dev/sdc bs=1024 seek=8
Adjust /dev/sdc to point to your sdcard !
2) You say nokia plug, are you using a nokia charger ? The A13 based
boards will draw up to 2A when charging, and most nokia chargers
cannot deal with this, this also likely explains why you also need
to hookup usb too. Make sure you've a decent 5v 2A power-supply
hooked up to the power-barrel
I cut a Nokia connector, and soldered the 2 wires on a USB 5V 2A charger.
3) The output you're seeing on the serial console is from the
part of the firmware which manages charging, if the battery is
too empty / your charger not powerful enough it will never get
past that. What you can do is:
a) insert microsd with u-boot from step 1.
b) press the power button for 12 seconds, this forces the board to go really
off.
c) press the power button for 4 seconds
The power button is broken, I have to see how to repair it, or just
make a contact between the 2 pins on the PCB.
Now you should see u-boot from the sd booting, and assuming only
the digitizer is broken and not the lcd you will also see a tux
on the lcd :)
If the lcd works, you can order a new digitizer here:
http://www.aliexpress.com/item/7-inch-Black-Touch-Screen-Digitizer-Glass-Touch-Panel-Allwinner-A13-Q8-tablet-pc-replacements-free/32213685488.html
This will cost you another 4 euro :)
But before doing so, measure the black bezel of the
digitizer on the top (camera) and bottom sides. On most tablets
it is 9 (top) / 10 (bottom) mm but on some it is only 7 / 8 mm,
the replacement digitizers by default are 9/10 and loosing 2 mm
of the screen on the top / bottom is quite annoying since that is
where status icons / start menu / etc. typically are.
If you've one of the 7 / 8 mm tablets, look at the part number
on the wire coming out of the digitizer and search for that
on ali express, likely you need this one:
http://www.aliexpress.com/item/Free-shipping-to-send-7-inches-100-original-brand-new-tablet-touchscreen-CZY6075E-FPC/32291760888.html
Note that the part-number is not only in the "subject" of the
advertisement but also in the "Model Number" entry in "item specifics"
this is important, otherwise you will still get the wrong digitizer.
Also note that this one is twice as expensive as the more standard one.
If the lcd is broken I would not bother with repairing the tablet,
if you want to replace the lcd you must also replace the battery
as their glue-ed together and forcibly removing the battery
will bend it, rendering it unusable (using bend lipo batteries
is a fire-hazard).
I hope this helps.
There is no way to boot a kernel without the need of the LCD or the
digittiser? Plain serial is fine for me.
Mainline u-boot and kernel will work fine without the lcd-panel / digitizer,
The lcd panel will be used regardless if it is there, if it is not
connected it will ofcourse not show anything, but u-boot / the kernel
will still think it is there, as all communication is one way only.
Regards,
Hans
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