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White screen

Posted: Sun Aug 12, 2018 11:46 am
by Marty33
Hello all.

I use Kedei HDMI screen.

For the 5V and GND, i soldered it on GPIO 2 and 6.

However, the screen stays white continuously.

The simple "hdmi" or "kedei" word do not appear... :?

any idea what the problem is?

Big thanks

Re: White screen

Posted: Sun Aug 12, 2018 12:18 pm
by ABH
Any pictures?
Check the screen ribbon cable maybe isn't seated properly.

Re: White screen

Posted: Sun Aug 12, 2018 12:23 pm
by VeteranGamer
Marty33 wrote:
Sun Aug 12, 2018 11:46 am
Hello all.

I use Kedei HDMI screen.

For the 5V and GND, i soldered it on GPIO 2 and 6.

However, the screen stays white continuously.

The simple "hdmi" or "kedei" word do not appear... :?

any idea what the problem is?

Big thanks


it will be either of these things.....

Firstly....
check that the ribbon cable is properly seated in the connector (for the HDMI screen and board)

Secondly.....
Check that your got proper power going to the screen (personally i'm not a fan of connecting it to the Pi, power it on its own)

Thirdly....
Where are you connecting the power of the screen to....
if its via the USB port, i would suggest to try this (also make sure you use a decent gauge wire, it trying this out)

Image




.

Re: White screen

Posted: Sun Aug 12, 2018 12:27 pm
by snoek09
I had the same problem with a Kedei screen and the third option fixed it for me back then.

Re: White screen

Posted: Sun Aug 12, 2018 3:47 pm
by Marty33
fourthly.... :lol:

Check if you remove polarizing filter.

On my white screen, the screen has glass aspect. Very shiny.

I test a second screen, i don't like the more satin aspect. I test it, COOL, it's working.

I remove this plastic, i put it all back together, happy, I test, no more image :shock: :shock: :shock:

I place this plastic on front and...... the image is revealed :shock: :shock:

The moral of the story : i kill 2 screens... :cry:

------------------

But it's strange, my old Kedei screen (on old GBZ), i don't have polarizing filter (and many resistor). And it work...

On top the new screen, bottom, the old :
Image

Re: White screen

Posted: Sun Aug 12, 2018 5:20 pm
by McGyver
Same for me: previous bought Kedai screens came with shiny glass, newer are with matt taped layer.

Re: White screen

Posted: Sun Aug 12, 2018 5:43 pm
by Marty33
Difference with quality ?
For me, a shiny screen is better. But I could be wrong...

I didn't know there were several versions :-(

I have an other screen, no resistors and no polarizing filter but without her original motherboard.
I test and he doesn't work with my actual motherboard (white screen but no image with polarizing filter).

I'm totaly lost...

Re: White screen

Posted: Mon Aug 13, 2018 1:11 am
by snoek09
You have no control of which version you'll get. Screenshots of the product don't mean a lot in this case.
If you can I would start using an SPI screen which are a lot cheaper.

Re: White screen

Posted: Mon Aug 13, 2018 6:17 am
by Marty33
I always had Kedei HDMI screens.

Do SPI screens have such good image quality?