Pi won't power up with screen connected, worked previously, help pls! [SOLVED]

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infinitLoop
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Re: Pi won't power up with screen connected, worked previously, help pls!

Post by infinitLoop » Mon May 20, 2019 12:59 pm

the spot you have the video connected to in the picture is a ground on the pi, so if you have both the video and the ground wires connected from the screen, to grounds at the pi, then that's why the pi is not booting. if you do like rodocop says and move the wire to the spot next to it (which, despite the confusing labeling, is actually the tv pin), it should work again. when you disconnect either of those two from grounds at the pi, your pi should boot, since it won't be shorting.

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Re: Pi won't power up with screen connected, worked previously, help pls!

Post by mrsippy » Mon May 20, 2019 1:28 pm

infinitLoop wrote:
Mon May 20, 2019 12:59 pm
the spot you have the video connected to in the picture is a ground on the pi, so if you have both the video and the ground wires connected from the screen, to grounds at the pi, then that's why the pi is not booting. if you do like rodocop says and move the wire to the spot next to it (which, despite the confusing labeling, is actually the tv pin), it should work again. when you disconnect either of those two from grounds at the pi, your pi should boot, since it won't be shorting.
Thank you infinitLoop, that makes sense (though it is odd that it was working previously), I shall try this shortly and report my results.

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Re: Pi won't power up with screen connected, worked previously, help pls!

Post by mrsippy » Mon May 20, 2019 3:10 pm

infinitLoop wrote:
Mon May 20, 2019 12:59 pm
the spot you have the video connected to in the picture is a ground on the pi, so if you have both the video and the ground wires connected from the screen, to grounds at the pi, then that's why the pi is not booting. if you do like rodocop says and move the wire to the spot next to it (which, despite the confusing labeling, is actually the tv pin), it should work again. when you disconnect either of those two from grounds at the pi, your pi should boot, since it won't be shorting.
This didn't work, but something interesting happened after I tried it... I put everything back how it was initially, plugged in the power, nothing. As I was reaching for the plug to pull the power, the black wire came away from the Pi (due to my sub-par soldering), the green light on the Pi lit up, and the display started flickering - only for a millisecond at a time, and very dimly, but enough that I could make it the boot sequence, and at one point I could see "AV1" in the top right corner. So the display still works! I'm not sure what to make of this exactly, but I plan next to completely replace the wires between the Pi and the display controller and see if that fixes it. That's a job for tomorrow though.

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Re: Pi won't power up with screen connected, worked previously, help pls!

Post by infinitLoop » Mon May 20, 2019 3:18 pm

mrsippy wrote:
Mon May 20, 2019 3:10 pm

This didn't work, but something interesting happened after I tried it... I put everything back how it was initially, plugged in the power, nothing. As I was reaching for the plug to pull the power, the black wire came away from the Pi (due to my sub-par soldering), the green light on the Pi lit up, and the display started flickering - only for a millisecond at a time, and very dimly, but enough that I could make it the boot sequence, and at one point I could see "AV1" in the top right corner. So the display still works! I'm not sure what to make of this exactly, but I plan next to completely replace the wires between the Pi and the display controller and see if that fixes it. That's a job for tomorrow though.
that sounds like a poor video connection now. make sure the video wire has a good solder connection, and also if you actually connect the ground that pad next to it, instead of on the gpio, that can help too (i usually twist those wires as well, to further increase the signal strength - the video signal isn't the strongest from the pi.)

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Re: Pi won't power up with screen connected, worked previously, help pls!

Post by rodocop » Mon May 20, 2019 6:24 pm

mrsippy wrote:
Mon May 20, 2019 1:28 pm
Thank you infinitLoop, that makes sense (though it is odd that it was working previously), I shall try this shortly and report my results.
Seems the reason it worked prior is because you had the green and yellow wires connected to those points. It would have been taking the video signal from the green wire, and just grounding the yellow.

In your later pictures you only have the yellow grounded and green not connected at all.

I agree that poor soldering may be an issue. Wires should not pull free when soldered.

You could also try the other AV (green wire instead of yellow). See if it performs any better.

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Re: Pi won't power up with screen connected, worked previously, help pls!

Post by mrsippy » Tue May 21, 2019 3:49 pm

I've just spent the last 2+ hours trying everything - I replaced the wires and re-attempted every suggestion in this thread. Nothing. No matter what, if the ground from the display controller was connected to the Pi, no matter where, the Pi would not power up. Remove the ground, Pi would power up, but no display. I was getting pretty fed up, had the ground connected, power plugged in, nothing happening, and I thought, "fuck it, I'm going to desolder the ground while the power's connected and see what happens". Guess what happened? The Pi started booting, and I got a flash of rainbow on the display, then it went black. Then I decided to resolder the ground while the Pi was booting, and it bloody worked! My display came to life and I watched the Pi boot sequence. I unplugged the power, plugged it back in, and it now works perfectly every time. What the actual fuck?

Thanks to all for your help, how do I mark this as resolved?

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Re: Pi won't power up with screen connected, worked previously, help pls!

Post by rodocop » Tue May 21, 2019 4:09 pm

mrsippy wrote:
Tue May 21, 2019 3:49 pm
I've just spent the last 2+ hours trying everything - I replaced the wires and re-attempted every suggestion in this thread. Nothing. No matter what, if the ground from the display controller was connected to the Pi, no matter where, the Pi would not power up. Remove the ground, Pi would power up, but no display. I was getting pretty fed up, had the ground connected, power plugged in, nothing happening, and I thought, "fuck it, I'm going to desolder the ground while the power's connected and see what happens". Guess what happened? The Pi started booting, and I got a flash of rainbow on the display, then it went black. Then I decided to resolder the ground while the Pi was booting, and it bloody worked! My display came to life and I watched the Pi boot sequence. I unplugged the power, plugged it back in, and it now works perfectly every time. What the actual fuck?

Thanks to all for your help, how do I mark this as resolved?
Just add [RESOLVED] or [SOLVED] to the title, maybe a mod will see it and move it to the resolved section. And that is very weird. Must have been something with the soldering I suspect. I don't recommend soldering with power running to the pi and the screen, but at least you were able to see instant results that way. I'm glad you got it working at least!

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Re: Pi won't power up with screen connected, worked previously, help pls!

Post by mrsippy » Tue May 21, 2019 4:14 pm

rodocop wrote:
Tue May 21, 2019 4:09 pm
mrsippy wrote:
Tue May 21, 2019 3:49 pm
I've just spent the last 2+ hours trying everything - I replaced the wires and re-attempted every suggestion in this thread. Nothing. No matter what, if the ground from the display controller was connected to the Pi, no matter where, the Pi would not power up. Remove the ground, Pi would power up, but no display. I was getting pretty fed up, had the ground connected, power plugged in, nothing happening, and I thought, "fuck it, I'm going to desolder the ground while the power's connected and see what happens". Guess what happened? The Pi started booting, and I got a flash of rainbow on the display, then it went black. Then I decided to resolder the ground while the Pi was booting, and it bloody worked! My display came to life and I watched the Pi boot sequence. I unplugged the power, plugged it back in, and it now works perfectly every time. What the actual fuck?

Thanks to all for your help, how do I mark this as resolved?
Just add [RESOLVED] or [SOLVED] to the title, maybe a mod will see it and move it to the resolved section. And that is very weird. Must have been something with the soldering I suspect. I don't recommend soldering with power running to the pi and the screen, but at least you were able to see instant results that way. I'm glad you got it working at least!
Yeah I figured it wasn't recommended, but, to be honest, I was about to completely give up and throw everything away anyways.

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