Full VGA resolution (640x480) 3.5" display, composite in

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rodocop
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Re: Full VGA resolution (640x480) 3.5" display, composite in

Post by rodocop » Tue Jun 25, 2019 11:05 am

Rowi wrote:
Tue Jun 25, 2019 10:15 am
Hi old threat but seems the experts are all here.

I wired everything - screen black. Pi boots normal.
Wired the button board for screen on the vga board -> Led on but screen still black.
Tired to change source but the screen just does not power on. The VGA Board has 5V and on the Controller Board for the Screen the 3,3V are also there.

We tried everything but it just does not cause any reaction by the screen. Any ideas?
Did you test the screen before wiring this way? Did you test with 12V and 5V? I have not used this screen with a pi 3 before, so I am not sure the exact test pad to use for video. Make sure you are using the right one. Also, you need to have a properly imaged SD card for anything to display. I see an SD card in there so I assume it's good.

You'll also use 5v not 3.3v. And make sure the ribbon cable is inserted properly. If you did not test and confirm it was working before hand, we have no way to tell if it ever worked in the first place. It may just be a bad screen that did not work from the start.

Also, FYI, the buttons board is not required to turn on the screen, once it detects a signal it should turn on.

You can also change the yellow wire to CVBS2 and see if it makes a difference.

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Re: Full VGA resolution (640x480) 3.5" display, composite in

Post by Rowi » Tue Jun 25, 2019 11:09 am

Hi thanks for your answer!

Nope we could not test the screen before.
The 3,3 V are to the button board of the screen.
5V are on the VGA Board as shown on the board (attachment).
What do you mean with test pad?
The Image on Raspi works (tested with hdmi).
Also inserted display_mode=3 for testing in config.txt... But does not change anything
We pluged the ribbon cable more than once - but there is only one way it goes in (if you look at it) and should be ok.

Sorry totally newbie :)
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Re: Full VGA resolution (640x480) 3.5" display, composite in

Post by rodocop » Tue Jun 25, 2019 11:17 am

Rowi wrote:
Tue Jun 25, 2019 11:09 am
Hi thanks for your answer!

Nope we could not test the screen before.
The 3,3 V are to the button board of the screen.
5V are on the VGA Board as shown on the board (attachment).
What do you mean with test pad?
The Image on Raspi works (tested with hdmi).
Also inserted display_mode=3 for testing in config.txt... But does not change anything
We pluged the ribbon cable more than once - but there is only one way it goes in (if you look at it) and should be ok.

Sorry totally newbie :)
By test pad. I mean the solder point on the pi 3. You have the yellow wire soldered to the pi. Make sure that is the correct spot.

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Re: Full VGA resolution (640x480) 3.5" display, composite in

Post by rodocop » Tue Jun 25, 2019 11:25 am

It should be pp24. And from your picture it seems that is where you have it wired....hmmm....

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Re: Full VGA resolution (640x480) 3.5" display, composite in

Post by Rowi » Tue Jun 25, 2019 11:37 am

yes I did my research but think I give up.... and buy a hdmi screen or use my second screen with dpi from tinkerboy.. a pitty screen was 60 dollars with the board

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Re: Full VGA resolution (640x480) 3.5" display, composite in

Post by rodocop » Tue Jun 25, 2019 11:47 am

Rowi wrote:
Tue Jun 25, 2019 11:37 am
yes I did my research but think I give up.... and buy a hdmi screen or use my second screen with dpi from tinkerboy.. a pitty screen was 60 dollars with the board
I see now from your other thread you had issues with the purchase, where they send the wrong driver board originally, and you ordered another separate one? Also you note the the ribbon is much longer on the screen, which is true compared to the one I have. I wonder if there is something with that screen, maybe it is not compatible? What was the original screen and board you received?

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Re: Full VGA resolution (640x480) 3.5" display, composite in

Post by Rowi » Tue Jun 25, 2019 12:20 pm

Hi it from here:
https://de.aliexpress.com/item/32845064 ... 4c4dLiMrBv

also thought the ribbion is too long but in the other version da was an extention and i looks the same.
They sent me a board for a 7 inch screen with 12V first (a black one) - so I just ordered a board for the PD035VX2.

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Re: Full VGA resolution (640x480) 3.5" display, composite in

Post by rodocop » Tue Jun 25, 2019 12:32 pm

yeah, strange. You might just have got some bad luck and have a non working screen. Not much else I can do to help.

Have you tried CVBS2 instead of the CVBS1?

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Re: Full VGA resolution (640x480) 3.5" display, composite in

Post by Rowi » Tue Jun 25, 2019 1:16 pm

will be the last try tommorow but should not make a difference

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