i press and hold vol- and power button but i dont can see any bird .
The birds are a ViewSonic-specific splash screen. It might be something else entirely on your LuvPad. Anyway, since your screen isn't displaying anything except white, looking for the boot splash screen is not useful.
in addition when i connect tablet to pc , i can see Tegra label in Device manager
even i test backlight sensor ,it work perfect then i think my issue is software.
Also led wifi is on
All of those point to a HW problem (cables, connector, LCD panel) rather than a SW one. The screen will go white when there is no video signal coming into the LCD panel. Then, only the backlight (white) will be displayed. (This is the reverse of what happens on a CRT monitor which displays black when it isn't receiving any signals.)
I would check those cable(s) and connectors again. Pull out all the cables going into the LCD panel
at both ends, and
inspect them carefully for breaks as
this thread recommends, then plug the cable(s) back in firmly.
Software checks are these.
1. Check bootloader.
Get the nvflash program (the ones used on this board might work too) and the bootloader.bin
for the LuvPad AD100 from one of the official firmware update files. Install the nvflash program (and, on Windows, its USB drivers) and then run this command (both the nvflash executable and bootloader.bin should be sitting in the same directory) in a CMD.exe window
after you've put the LuvPad into APX mode (on the gTablet, you have to power off, then press both the Vol [-] and the Power buttons--it might be some other button combination on the LuvPad):
Code:
C:\SOME\PATH> [B].\nvflash --bl bootloader.bin --getpartitiontable part.txt[/B]
If the command completes and the
part.txt file looks OK, then your LuvPad is running the bootloader just fine.
2. Check Recovery.
Power off the LuvPad, then try putting it into Recovery mode by pressing the Vol [+] and Power buttons at the same time. (Again, those keys work on the gTablet; it might be something else on the LuvPad). After a few seconds, see if you can get into an ADB shell (install ADB first if you need to, or just
use Linux). If you have CWM, or some other kind of custom recovery installed, then you will get a shell. The stock recovery may or may not give you a shell.
Code:
C:\SOME\PATH> [B]adb shell[/B]
3. Check ROM.
Power off the LuvPad, then run this adb command and power on the LuvPad. If you've enabled ADB debugging in the ROM (or, it comes enabled by default) and the ROM doesn't have problems booting, then you should see the system logs scrolling by.
Code:
C:\SOME\PATH> [B]adb logcat -v time[/B]
Also, in both the ROM and in recovery mode, if when you connect and disconnect the USB cable, Windows detects the device connection/disconnection, then the HW and ROM/recover are most probably OK, and you may be able to look at the logs to troubleshoot this further. (When you connect the cable in the ROM, a new removable drive may even appear, even though it may show no data in it--I don't use Windows, so I don't know precisely what should happen there.)