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Display white (not working)
Posted: Thu Sep 17, 2015 5:18 pm
by DerberMohikaner
Hi,
I have just received my eagerly awaited official pi display. I assembled as shown in the video. Unfortunately my screen turns only white during boot up.
The display is attached to a Raspberry Pi 2 Modell B. Both units are powered by individual power supplies.
After reading in the forum I have done so far:
sudo apt-get update
sudo apt-get upgrade
sudo reboot
sudo rpi-update
Help would be much appreciated.
Thanks
Ben
Re: Display white (not working)
Posted: Thu Sep 17, 2015 7:11 pm
by JimmyN
Check the ribbon cable connection from the display to the interface board, the cable is probably not seated all the way into the connector. It will be the connecter underneath the interface that you can't see when it's fastened in place, you'll have to remove it to have a look.
Re: Display white (not working)
Posted: Thu Sep 17, 2015 7:19 pm
by gsh
If it turns white, that means that it has been detected by the Raspberry Pi firmware, this means that the DSI communication between the Pi and the display board is good. But the data isn't correctly getting through to the display. So as JimmyN says it's likely to be the big DPI connector that's the problem...
I'd suggest unscrewing everything and make sure it is seated properly, it doesn't need lots of force to get the FPC (flexible printed circuit) into the connector, so a good jiggle should get it home properly
Gordon
Re: Display white (not working)
Posted: Thu Sep 17, 2015 7:31 pm
by JimmyN
gsh wrote:FPC (flexible printed circuit)Gordon
Ahhhh, an FPC, I'll have to remember that. I figured there was probably a specific name for it, but not knowing I've always just called them ribbon cables.
Re: Display white (not working)
Posted: Fri Sep 18, 2015 7:26 am
by DerberMohikaner
Thanks to both of you!
I have by now assambled and disassembled and reassambled numerous times. Unfortunately to no avail. My display is not willing to show something of interest. At startup it's black and during bootup it just turns bright white.
What could be the reason for this strange behaviour?
Thanks for interest and help.
Ben
Re: Display white (not working)
Posted: Fri Sep 18, 2015 7:50 am
by gsh
What does lsmod give you?
Also try:
sudo apt-get install evtest
evtest
(select the events from rpi-ft5406)
Touch the screen, does that work?
Gordon
Re: Display white (not working)
Posted: Fri Sep 18, 2015 8:36 am
by DerberMohikaner
What does lsmod give you?
What is ismod?
sudo apt-get install evtest
evtest
(select the events from rpi-ft5406)
Touch the screen, does that work?
I will try and report.
Thank you
Re: Display white (not working)
Posted: Fri Sep 18, 2015 8:39 am
by fruitoftheloom
DerberMohikaner wrote:What does lsmod give you?
What is ismod?
http://linux.die.net/man/8/lsmod
Re: Display white (not working)
Posted: Fri Sep 18, 2015 8:58 am
by DerberMohikaner
After installing evtest:
No device specified, trying to scan all of /dev/input/event*
Not running as root, no devices may be available.
Available devices:
/dev/input/event0: Logitech USB Receiver
/dev/input/event1: Logitech USB Receiver
Select the device event number [0-1]: quit
USAGE:
Grab mode:
evtest /dev/input/eventX
Query mode: (check exit code)
evtest --query /dev/input/eventX <type> <value>
<type> is one of: EV_KEY, EV_SW, EV_LED, EV_SND
<value> can either be a numerical value, or the textual name of the
key/switch/LED/sound being queried (e.g. SW_DOCK).
How to better this? (as is obvious: I'm an absolut beginner)
Thanks for help
Ben
Re: Display white (not working)
Posted: Fri Sep 18, 2015 9:03 am
by scotty101
One (or more) of your cables is loose.
Re: Display white (not working)
Posted: Fri Sep 18, 2015 10:05 am
by DerberMohikaner
Thank you.
I have 3 different Pi's at my disposal. None is displaying anything on this display.
For me it's hard to believe that a faulty inserted cable could be the source for this trouble.
I will ask a friend to assemble one.
Re: Display white (not working)
Posted: Fri Sep 18, 2015 11:03 am
by tvjon
No idea if it'll help you, but I notice that when I shutdown the RPi (via the Raspbian menu option) I have to also manually switch off the display power (currently that's on its own 3.3 volt psu) otherwise the RPi appears to boot ok, but nothing on the LCD.
Switching off, then on, the display, then RPi, & booting occurs normally.
Re: Display white (not working)
Posted: Fri Sep 18, 2015 11:48 am
by Pi_Fanatic
Two power supplies is overkill unless you are powering several devices from your Pi USB ports. Connect the two GPIO cables that are included (not all four) from the Pi (5V and GND GPIO) to to the display board (5V and GND Pins) and power your Pi with a 2A fixed cord power supply (not a cell phone power supply with a USB cable). There is no need to power both boards separately unless you have a unqiue setup that requires that.
Pi_Fanatic
Re: Display white (not working)
Posted: Fri Sep 18, 2015 12:16 pm
by fruitoftheloom
Pi_Fanatic wrote:Two power supplies is overkill unless you are powering several devices from your Pi USB ports. Connect the two GPIO cables that are included (not all four) from the Pi (5V and GND GPIO) to to the display board (5V and GND Pins) and power your Pi with a 2A fixed cord power supply (not a cell phone power supply with a USB cable). There is no need to power both boards separately unless you have a unqiue setup that requires that.
Pi_Fanatic
Yes for completeness see:
http://www.element14.com/community/docs ... OUCHSCREEN
Re: Display white (not working)
Posted: Fri Sep 18, 2015 4:52 pm
by MegaGumbo
Same thing here, got my LCD Touchscreen today, followed the instructions and all i get is a white screen. Checked the connections of all wires twice. It's a Raspberry Pi2 I got connected here.
EDIT: nevermind. The display ribbon cable got loose both times after I fixed the controller board to the display. The clamp on the controler board got loose on one side. It's now working (yippie!
) but if you also encounter that white screen effect, the guys above are right:
check your cable connections. And
be careful while fixing the controller board to the back of the display. Otherwise the display ribbon cable may come loose again.
Re: Display white (not working)
Posted: Sat Sep 19, 2015 11:05 pm
by jzkmath
I have the same problem, except that after spending a constant 3 hours of adjusting the ribbon cable, got me nowhere!
I'm rather upset because I've literally tried everything.
Re: Display white (not working)
Posted: Tue Oct 13, 2015 6:56 pm
by DerberMohikaner
Hi,
the proper solution was to sent back the display for further scrutiny by the proper experts which resulted in a complete refund.
So, case is closed. Unfortunately, I have to wait quite a long while for the new display.
Case closed. Thanks to all contributars.
Ben