Problem with 32x64 matrix (using RPi and HAT)

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GreenRay
 
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Problem with 32x64 matrix (using RPi and HAT)

Post by GreenRay »

Hello!

I just bought a 32x64 rgb led matrix and a HAT to my Raspberry Pi B+. When I am running the test program, there is an problem...

Colum 48 to 64 is slightly darker, and it's blinking.

I tried to search the Internet, but did not find any solution. So, do some of you know anyting that can help?

Image

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adafruit_support_rick
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by adafruit_support_rick »

Please post clear pictures of your wiring and soldering.

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GreenRay
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by GreenRay »

The Matrix is powered through the matrix HAT, and the flat cable is connected between the JIN1 and the HUB75 connection on the HAT.

The Pi gets power from the micro usb, and the HAT is connected to an 5v, 4A power supply (everything, exept the Pi, is bought from you, AdaFruit :)

Have note connected any battery to the RTC.

Image

Image
Can't see any problem here?

I took a look on the back side of the matrix, and found an "open" connection. The paint vas scratcht away, and I could see the copper. Could this be an bad connection?

The "wire" is connected to the U2 and U5 chip.

Image

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adafruit_support_rick
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by adafruit_support_rick »

Is that trace broken? It looks that way in the picture.

Please email [email protected] with a link to this thread for a replacement matrix.

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GreenRay
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by GreenRay »

I can't see if its broken or not. It also looks like the C102 has been broken off (don't know if it should be a component there or not)

Is it possible to get a drawing of the wiring? And a component list?

Have sent an email. Thank's for the help!

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pburgess
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by pburgess »

Regarding C102: are the solder pads smooth, or do they look jagged like a component was sheared off there?

These panels come in several sizes and unfortunately I don't have that particular one on-hand. It's normal for some spots to be unpopulated depending on the specific production run...but I can't say if that's a "normal" unpopulated spot or an "oops" spot. It'd be handy to know for the future in case others encounter the same symptoms. Thanks!

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GreenRay
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by GreenRay »

The solder pads looks a bit jagged, not so smooth like the other empty pads.

Thanks for the comment :)

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pburgess
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by pburgess »

Other question: is the B+ being overclocked at all? If so, what settings exactly? Thanks.

Noticing a rash of these problems lately and it might turn out to be just software related.

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GreenRay
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by GreenRay »

Hello again!

The B+ is straight from the store, and I did not overclocke it.

AND I got the new panel today. This one have the c102 component :) But, still have the same problem... Colum 48 to 64 is slightly darker, and it's blinking.

What now? Could it be any problem with the Pi HAT? Or maby the Pi?

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pburgess
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by pburgess »

In at least one prior situation, dark columns like that were the result of a poor ground connection (there's several on the socket connector, and apparently it does make a difference whether they're all connected, even though you'd think they all go the same place). Two things to try:

1. If you swapped out just the panel but kept the old ribbon cable...swap out the cable as well. It's possible for these to get pressed wrong, where one or more wires don't make a connection.

2. Possibly a cold solder joint on the Pi HAT. It's hard to tell in a photo, sometimes they just catch the light funny, but a few looked suspect. For good measure, I'd go over ALL the header pins and re-heat them, making sure the solder flows onto the pads. Ditto with the header that plugs into the Pi.
cold-joints.jpg
cold-joints.jpg (53.89 KiB) Viewed 624 times

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GreenRay
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by GreenRay »

Still have the same problem...

BTW: Where can I buy a longer flat cable?

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pburgess
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by pburgess »

Strange. Let's replace the Matrix HAT then. Email [email protected] with a link to this post.

If that doesn't resolve it, I might ask for a matrix and HAT to be shipped back for forensics.

For special ribbon cables, usually I press my own, with IDC connectors from DigiKey or other such parts suppliers. There's a special crimping tool for this (got mine from Radio Shack like 4,000 years ago, don't know if they still sell this), but a bench vise can work in a pinch.

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eponymic
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by eponymic »

I am having a very similar issue. I have used 2 different RPi 2s and 2 different hats and 2 different led panels. I also had someone else, who was more experienced in soldering build the second hat board. No matter what combination I used the result was the same. The last dozen or more columns do not light when using the demos or my own python scripts. Does someone know of another library we could try? At this point it has to be software I would guess.

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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by adafruit_support_rick »

Please post clear, detailed pictures of both sides of the hat, showing your soldering and wiring to the matrix.

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eponymic
 
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Re: Problem with 32x64 matrix (using RPi and HAT)

Post by eponymic »

Thanks for he quick response. Here are some pics. Today I also checked out a fresh copy of the code with subversion.
Attachments
Bottom.jpg
Bottom.jpg (99.54 KiB) Viewed 565 times
Top_Solders.jpg
Top_Solders.jpg (130.47 KiB) Viewed 565 times
Wiring.jpg
Wiring.jpg (97.05 KiB) Viewed 565 times

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