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left half of 64x64 RGB LED matrix - ghosting and unintention
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left half of 64x64 RGB LED matrix - ghosting and unintention

by hilljmd on Tue Oct 20, 2020 12:58 pm

Components:
* 64x64 RGB LED Matrix - 2.5mm Pitch - 1/32 Scan: https://www.adafruit.com/product/3649
* RGB Matrix Bonnet for Raspberry Pi: https://www.adafruit.com/product/3211
* 5V 10A switching power supply: https://www.adafruit.com/product/658

Info:
* I soldered the jumper on the bonnet to support the 64x64 matrix as instructed here: https://learn.adafruit.com/adafruit-rgb ... g-matrices
* I have used the bonnet and matrix with a RPi 4, 3B+ and 2, and it behaves exactly the same way.

For direction purposes, the data input is at the bottom, and the LED matrix is face up.

When I run any of the demos the left half of the matrix displays correctly. The upper right half has a lot of ghosting green pixels in the columns with intentionally lit pixels, and the bottom right half has ghosting pixels and unintentionally lit pixels in the columns with intentionally lit pixels.

I've followed all of the troubleshooting steps with the different command line arguments and none of them improve the situation.

Is this a problem with the 64x64 matrix, or the RGB Matrix bonnet? Or is there some other troubleshooting I should try?
Attachments
64x64-led-matrix-issues.jpg
64x64-led-matrix-issues.jpg (693.57 KiB) Viewed 196 times

hilljmd
 
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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by adafruit_support_carter on Tue Oct 20, 2020 5:41 pm

Please post a photo of both sides of the HAT so we can check for any possible soldering or other hardware issues with the HAT itself.

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by hilljmd on Wed Oct 21, 2020 2:16 pm

Posting top and bottom photos of the RGB Matrix Bonnet
Attachments
RGB Matrix Bonnet - Bottom.jpg
RGB Matrix Bonnet - Bottom.jpg (480.72 KiB) Viewed 181 times
RGB Matrix Bonnet - Top.jpg
RGB Matrix Bonnet - Top.jpg (550.15 KiB) Viewed 181 times

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by adafruit_support_carter on Wed Oct 21, 2020 5:57 pm

Thanks for the excellent photos.

Is it possible the solder jumper is shorting to 16 as well? Looks like there might be a little bit of a solder bridge?
jumper.jpg
jumper.jpg (17.28 KiB) Viewed 176 times

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by hilljmd on Wed Oct 21, 2020 10:26 pm

That's just a reflection of the light off some flux or melted lacquer from the board, there wasn't any solder bridging the gap. But, just to be sure it wasn't establishing a connection, I scraped the gap between the two pads with an X-acto knife. See new "scraped bonnet" picture. Still no improvement in the LED matrix ghosting issue.

I took a look at the back of the matrix itself - see the "back of led matrix" picture. I noticed there's a marker for a large capacitor that isn't populated (drew a little box around it in the image). When I look at the back of the matrix on the catalog page (https://www.adafruit.com/product/3649) I see that all of the large capacitor markers have been populated. The missing capacitor is on the side of the display that is malfunctioning. If that's indeed the problem, can I get a replacement matrix?
Attachments
back-of-led-matrix.png
back-of-led-matrix.png (931.61 KiB) Viewed 171 times
scraped-bonnet.jpg
scraped-bonnet.jpg (632.36 KiB) Viewed 171 times

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by adafruit_support_carter on Thu Oct 22, 2020 11:39 am

Thanks for the additional photos. The soldering on the bonnet jumper does look fine. I think those footprints on the matrix are normal. There can be variation relative to the product photo (something we can't control).

For direction purposes, the data input is at the bottom, and the LED matrix is face up.

You are connecting to this input?
input.jpg
input.jpg (120.46 KiB) Viewed 164 times


I've followed all of the troubleshooting steps with the different command line arguments and none of them improve the situation.

That included trying various --led-slowdown= options?

There's a chance this is still something software related as well. The Pi has a few gotchas that can happen. When you ran the install script, did you select the "quality" or "convenience" option? What operating system image are you working from?

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by hilljmd on Thu Oct 22, 2020 12:41 pm

Yes, that's where I'm plugging in the ribbon cable.

Yes, I ran through all permissible values for the "--led-slowdown-gpio=" flag. On all three rpi devices.

In the installation script I selected the "convenience" option

Installed OS:
On the rpi4: Raspian GNU/Linux 10 (buster)
On the rpi3B+: Raspian GNU/Linux 9 (stretch)
On the rpi2: Raspian GNU/Linux 7 (wheezy)

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by hilljmd on Thu Oct 22, 2020 1:20 pm

I installed a jumper from 4 to 18 and reinstalled the software with the "quality" option. Confirmed audio system is off. On rpi 2, 3B+, and 4.

No change to the issue.

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by adafruit_support_carter on Thu Oct 22, 2020 2:00 pm

Hmmm. OK. Thanks for all the checks and verification. We can try a replacement matrix and see what happens. Send an email to support@adafruit.com with a link to this thread and your order number and they can send you a replacement matrix.

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by hilljmd on Thu Oct 29, 2020 10:14 pm

I bought a second 64x64 LED MATRIX and a second BONNET. I set up the 2nd bonnet for high-quality mode (soldered the jumper pads, and jumped pins 4 and 18). I replaced the 1st bonnet, leaving everything else the same. The first LED matrix works fine on the 2nd bonnet, as does the 2nd LED matrix.

On the 1st bonnet I removed the solder from the jumper pads and re-soldered it, just in case I wasn't getting a good connection. Tried the 1st bonnet with the 1st and 2nd matrix, and the issue happened on both of them.

I'm pretty confident there's a problem with the 1st bonnet. If there's any more troubleshooting to be done, please let me know and I'll give it a try. Otherwise, perhaps a replacement?

Separate note: I did process the RMA request for the 1st matrix, and one has been shipped to me. I'll send a note to support to figure out how to send it back after it arrives.

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by adafruit_support_carter on Fri Oct 30, 2020 3:04 pm

Ugh. OK. That does seem to point to the Bonnet now. So let's replace that.

Send *another* email to support and point again to this thread. This time they can send you a replacement Matrix Bonnet.

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by hdmoore on Wed Nov 11, 2020 7:27 pm

I believe I have the same issue, configured the same, but assumed it was a software problem. Glad to hear that this is bonnet and not a matrix issue. I will reach out to support as well.

ghost.png
ghost.png (365.5 KiB) Viewed 53 times

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Re: left half of 64x64 RGB LED matrix - ghosting and uninten

by adafruit_support_carter on Wed Nov 11, 2020 7:29 pm

@hdmoore Please start a new thread for your issue. If you email support, they will just send you back here to the forums to attempt technical troubleshooting first.

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Please be positive and constructive with your questions and comments.