Portable Pi - Display weirdness... colecago?

Hey there!

I am inching closer and closer to completion of my portable pi!

I've run into some weirdness though.

When I power up the display, (add the 7.4v and ground to the header) The screen lights up all white. Even if there is no video source. This is a contridiction to what usually happens when the display is powered, as it waits for video signal.

Also, adding the video signal doesn't seem to actually turn the display on or do anything. Do you think it's an issue physically with the display? Any thing I'm missing?

I assumed that the red and black were 12v (we are using 7.4 and ground) and yellow was video signal, (White audio) Was this a good assumption?

--Josh

@colecago

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colecago over 13 years ago

Does it not light up on 12V with no video? It's been awhile since I've played with the project, I don't remember if our lighted up before it had video or not at 7.4V. I do remember though, if below 6.5ishV it would be lit up and not show anything if there was good video or not, some undervoltage thing with the display. I would check what voltage your batteries are at to see if this is the issue.
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bikr over 13 years ago in reply to colecago

Out of the box, It doesn't light without video signal It stays dark until signal is on. For some reason at 7.4v this is lighting up like a xmas tree but not showing anything from signal. It could be a source issue, but the display lighting up alerted me.
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colecago over 13 years ago in reply to bikr

Check the voltage of the batteries while loaded, could be the undervoltage issue similar to what we saw.
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bikr over 13 years ago in reply to colecago

Batteries are putting out 7.94v to the display. Still just white screen nada.

I'm going to pull another screen apart and test some stuff... But Anything off the top of your head?

I also just ordered a Bench Supply to help narrow down if the new lcd board has higher requirements.
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colecago over 13 years ago in reply to bikr

That's a good idea. When we design the next board we will have it somewhat adjustable (solder jumpers) on what the screen voltage should be. It will be more universal then.
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e14 Contributor over 12 years ago in reply to colecago

try unplugging audio from the white. that is usually used for a 2nd camera
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colecago over 12 years ago in reply to e14 Contributor

Actually I think the white is a signal from the reverse or something to signal the screen to turn on, if you leave it floating it usually works fine, but I wouldn't put audio in it.

*Edit, it is a second video source, I think it overrides the main video when a signal is present for reversing*
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colecago over 12 years ago in reply to e14 Contributor

Actually I think the white is a signal from the reverse or something to signal the screen to turn on, if you leave it floating it usually works fine, but I wouldn't put audio in it.

*Edit, it is a second video source, I think it overrides the main video when a signal is present for reversing*
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