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Problem with BW3,5 Screen

Posted: Sat Jun 23, 2018 4:53 pm
by Ludaris
Hey,

I bought the BW 3.5 screen from Amazon and got the Variant "'InnoLux' Ebay screen"
(Found in the Sudomod Wiki. Link:https://www.sudomod.com/wiki/index.php/GBZ_Screen).
The display works so far perfectly with 12V. As soon as I connect 5V to it, the screen starts flickering, which was also predictable, since the whole screen is designed for 12V.

So I did the modification as in the picture of variant "'InnoLux' Ebay screen" shown and tested it.
Now to the problem:
As long as the Raspberry Pi Zero is running and I'm doing the modification while the PI is still running, everything works as it should.
But if I solder the wire like the picture is showing, and then start the PI, it wont boot anymore.
Only when im removing the wire, starting the PI to boot up and then connect the wire back it will work perfectly.
I also have the cable lengths already cut to the minimum, without success.

Anymore ideas?
The IC on which the modification was performed is called "rzc2013" and the pin is called "SW".


Thanks in advance for any tips.

~Ludaris

P.S.: I attach some picture of my actual screen maybe it is different to the Variant "'InnoLux' Ebay screen" but i dont think so.
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20180615_171700-min.jpg (1.34 MiB) Viewed 2374 times

Re: Problem with BW3,5 Screen

Posted: Sun Jun 24, 2018 1:07 pm
by Ludaris
Hey,

I have found the solution for my problem now.

For those of you who are interested in the solution and have the same screen control board as me (see the pictures in the first post) here is a possible solution which worked just fine for me:

The "rzc2013" IC is a buck converter which downgrades the input voltage from 12V to 5V.
Since we do not need this buck converter, I have completely desoldered it.
Then I have soldered the 5V input voltage of the Raspberry PI (PP1) directly to PIN 3 (SW) to the pad where formerly the IC was soldered to.
The ground and the TV signal (yellow wire) I left them there as it was before.
And lo and behold, everything works as it should. The Raspberry PI boots up normally and the screen does not flicker anymore.


Here are some pictures for an easier understandment:
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~Ludaris