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Voltage regulation issue? Flickering on LED matrix
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Voltage regulation issue? Flickering on LED matrix

by BeeHD on Wed Nov 18, 2020 11:33 pm

I ordered a 64x32 Flexible RGB LED Matrix - 5mm Pitch and matrix portal. I followed a super great installation guide to make a live metro sign: https://github.com/metro-sign/dc-metro

I am pretty new to this stuff, but everything went fine during the setup and use of the portal and LED screen. That is with exception to one area of the matrix which has non stop flickering around the text. See video of the issue: https://youtu.be/1iw-PxnscyQ

Because the flickering is confined to one specific area of the matrix (upper left) and that it is randomly cycling through green and red around the text itself, I am inclined to believe that this is a voltage regulation issue and that one of the controllers on the back of the matrix is busted. When I reset/reinstall the matrix portal, the circuit python logo also has this same issue. After doing a bit of research, I don't think this is a refresh or PWM width issue. The text is lit up solid and looks fine, it is the LEDs around the text that is sporadic and flickering non-stop.

I have tried different power sources and I have reset and reinstalled cpython on the matrix. I know in the video I have the screen slightly propped up but the flickering remains even if it isn't propped up. As I said, I am fairly certain it is a hardware issue. The display arrived today and is brand new.

Any thoughts?

BeeHD
 
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Re: Voltage regulation issue? Flickering on LED matrix

by BeeHD on Thu Nov 19, 2020 5:34 pm

Also my invoice number is :2404905

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Re: Voltage regulation issue? Flickering on LED matrix

by BeeHD on Mon Nov 23, 2020 5:05 pm

I can get the flickering to stop on one portion of the board if I put my finger on one of the ICs. The screen is defective.

here is me putting my finger on the IC and stopping the flickering: https://youtu.be/ktH6NOSEV8k

BeeHD
 
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Re: Voltage regulation issue? Flickering on LED matrix

by mikeysklar on Tue Nov 24, 2020 6:43 pm

@BeeHD,

Go ahead and drop in e-mail to support@adafruit.com and link them to this forum thread. This sounds like a defective screen and should be replaced.

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Re: Voltage regulation issue? Flickering on LED matrix

by BeeHD on Mon Nov 30, 2020 9:04 am

I received a replacement screen and unfortunately they both screens exhibit the same issue. The erratic flickering in the same area of the screen. I daisy chained both screens to the same Matrix Portal and you can clearly see that the issue persists. https://youtu.be/2duPV4MJ0ew I tired new projects and the issue remains no matter what.

So now I think that it is actually the matrix hardware that is broken?? Is this something that you have seen before? anything I can do? As I mentioned, I have tried 4 different power supplies.

If I could get a new portal I would gladly return the replacement screen that is probably functional. This has turned into quite a debacle for me... I just want it to work correctly.

BeeHD
 
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Re: Voltage regulation issue? Flickering on LED matrix

by mikeysklar on Mon Nov 30, 2020 6:21 pm

Can you post a picture of which chip that you put your finger on stabilizes the screen image?

We'll swap the matrix hardware next since that appears to be necessary, but I want to better understand if the chip is not full soldered, seated or if there is a related connection that is loose.

Thanks for the video. That helps with showing the image noise.

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Re: Voltage regulation issue? Flickering on LED matrix

by BeeHD on Tue Dec 01, 2020 12:11 pm

See the attached picture:

image0 (1).jpeg
image0 (1).jpeg (610.34 KiB) Viewed 43 times


When placing my finger over the left side of the IC the flickering stops. it is not like I am forcing the IC into the board, I am just gently bridging the left contacts (as in the picture). It is important to note that the the flickering only stops about 6 pixels (LEDS) down but still will continue further down the upper left portion of the screen (See the video a few posts above of me demoing this). If I hold my finger over other ICs where the flickering remains, I get weird colors and it doesn't solve anything. This is the same on both screens.

I am quite stumped by this. I think the matrix portal controller must be the source of this issue and needs a replacement because the issue was exactly the same on both screens.

BeeHD
 
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Re: Voltage regulation issue? Flickering on LED matrix

by BeeHD on Tue Dec 01, 2020 12:28 pm

Another development:I was playing with the screen a bit more, feeling around the back and if I put my finger here I get even more of a response on the screen:

image0 (2).jpeg
image0 (2).jpeg (590.73 KiB) Viewed 43 times


Here is a video of what it does: https://youtu.be/PpsUCKtqDQo

It stops the flickering in the top 6 leds just like when I put my finger on the IC but it also shifts everything over. I am really not pushing very hard into the screen to make it happen. and as you can see in the image my finger isnt even on an IC for it to happen. Now I am back to thinking that the screens are possibly defective.... ahahah

It might be worth trying this with some of the 64x32 flex screens you have in the shop to see if you can replicate this issue. Bizarre

BeeHD
 
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Re: Voltage regulation issue? Flickering on LED matrix

by mikeysklar on Tue Dec 01, 2020 7:35 pm

BeeHD,

Can you take a closeup photo of the UR4 IC your finger is near. I wanted to see if there was any compromised solder points on that IC.

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Re: Voltage regulation issue? Flickering on LED matrix

by BeeHD on Wed Dec 02, 2020 9:56 am

Both screens have the same issue and both of the ICS look fine visually See attached photos of both of them:

1.jpeg
1.jpeg (699.22 KiB) Viewed 21 times


2.jpeg
2.jpeg (586.42 KiB) Viewed 21 times


4.jpeg
4.jpeg (368.58 KiB) Viewed 21 times


All the hardware looks fine but has the issue. I will post a pic of the matrix portal, which also looks fine. What should I do? Can you test this on your screen? do you think the matrix portal is the issue, because I am seeing this on both screens?

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Re: Voltage regulation issue? Flickering on LED matrix

by BeeHD on Wed Dec 02, 2020 9:57 am

Matrix portal looks fine:

3.jpeg
3.jpeg (646.25 KiB) Viewed 21 times

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Re: Voltage regulation issue? Flickering on LED matrix

by mikeysklar on Wed Dec 02, 2020 3:21 pm

Thank you for the excellent photos.

I don't have a Matrix display, but it sure looks to me like the entire right side of the UR4 component is not soldered. If that is the case there could be a bad batch that went out.

I will pass this onto engineering to look into and get back to you shortly.

What were the dates you received each unit (approximately)?

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Re: Voltage regulation issue? Flickering on LED matrix

by BeeHD on Wed Dec 02, 2020 3:39 pm

Very keen eye. I totally see what you are talking about. Many of the ICs are not fully soldered here is another good picture:

5.jpeg
5.jpeg (545.68 KiB) Viewed 16 times


First screen arrived Nov 18th the second replacement arrived Nov 27th. Both defective. Let me know if I can provide anymore information. Like I mentioned, I just want a working matrix screen ahaha

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Please be positive and constructive with your questions and comments.