A new screen, any tips on 5v conversion?

[fcib]

I have the same board as seen here:
http://sudomod.com/forum/viewtopic.php? ... 420#p19050

Seems like this guy (and me) have no solution. It isn't on the screen wiki so I'm not sure how to convert it for 5v (if its even possible).

I got it from amazon, seller "GoodWill Sky" since they were the first one I found that shipped to Australia.

When hooked up by 5v (from my powerboost its ~5.12V according to multimeter) and with the video signal connected, the screen is on and displays the image, but the picture is barely visible and very dim.

Any advice?

[Justblair]

Got a multimeter?

I am going to guess (picture not clear that the three legged componnent marked U2 is a 3.3v voltage regulator. If you measure the voltage on the three pins smaller pins (with the screen powered), there is a good chance that one will measure 5v.

There are also unpopulated pins above C38 and R28. I would not be suprised to find out that one is gnd and the other either 3.3 or 5v.

[fcib]

The unpopulated pins are for the controller board which his doesn't have, mine does.

The regulator has a datasheet http://www.advanced-monolithic.com/pdf/ds1117.pdf

Could I just remove it altogether and wire pin 2 to pin 3? Vo to Vi, or is that not what I'm supposed to do?

Now that I look at the sheet again, it says that the AMS1117 comes in multiple packages, one of which looks like that 4 pin chip, but it could also be the 8 pin chip. i'll have to check the numbers printed on it tomorrow.

[fcib]

Well nothing with that regulator seems to help. Maybe somebody here has a suggestion that will work.

For now I just undid my changes and it's back to how it was before. Very dim, hard to see but working.

[chaosratt]

Ahh, I completely forgot that guy! Got that one as my first screen, promptly broke it too (dropped it )
I'll update the wiki when I get a moment, in the mean time, see pic:

[fcib]

Thanks for the tip. I already attempted that. The image was more stable (no flashing/cutting out/turning off), but still very dim. I think maybe the backlight is fried or I damaged it somehow because I found another source that suggests I do the same thing.

Meh, Ordered a new screen that should have a more common, easy to mod board.

[TimBer]

I also have this board and performed this modification.

The screen brightness and all is similar to all the BW screens, so indeed, perhaps something is fried

[mike_louisxvi]

Hey all, I am the guy from the initial post that was linked here. Thank you all for helping figure this screen out.

Being a total novice, as stated before, I am just sort of following directions as I see them (I can just barely understand some of this stuff ). That being said... so the only thing I would have to do to get this to work is take a wire (I am using 24 gauge, is that too thin?) and solder it onto the power wire connection and the other end to the third pin on that regulator?

Would I be able to test this connection by wiring up the power cable that came with the screen to a USB wire and then plug that into a 5V wall plug to see if this works once I solder the board? I can post pictures of what I'm talking about tomorrow if that works, and a better one of the board if anyone needs it.

Sorry, I'm certainly at the mercy of those of you that know this stuff really well! I really appreciate everybody's help!

[mike_louisxvi]

Okay, I have an update on my screen.

I wound up wiring a 22 gauge red jumper wire like in the picture. I used a more rigid, bendy copper wire than the other wires I was using, so hopefully that was the right choice. My soldering isn't the best, and it kind of lifted the initial red wire out of the contact point, but the solder is holding both of them in place, just a little higher up off of the board.

Here is a photo of this:

IMG_0480.JPG (2.5 MiB) Viewed 11186 times

Like I mentioned before, I wired up the power cable that came with the camera to a 99cent store USB, disregarding the two data wires:

IMG_0478.JPG (2.06 MiB) Viewed 11186 times

Which is plugged into a 5 volt (5.1 actually, i think) power block from a chomecast I had laying around.

IMG_0479.JPG (2.22 MiB) Viewed 11186 times

I then used a gamecube to plug the composites into the wires that were given with the screen, which is wired up to the board

IMG_0477.JPG (2.63 MiB) Viewed 11186 times

I got everything wired up and....the screen didn't turn on

I fiddled with the ribbon, which is held in by a clasp, and I started seeing something..a flicker. At this point, I'm stuck with this flickering screen, which I feel is a better sign than it not working, but I'm not sure where to go from here. It seems like it just probably need some simple modification. I used my multimeter (a tool I havent used before and need to learn more about), and when I set it to the "10V" setting then probed the ground and end of the jumper wire, it said ".58"

Heres a gif of the flicker. In reality, it looks much clearer, and the brightness seems good.



I appreciate everyones helpful comments. Any idea of where to go from here?

[fcib]

Not sure if the yellow and white cable are for the yellow and white wire, but you only need one when soldering to the pi.

It might be switching between av1/av2 constantly? Try just using one.