Keep breaking LED displays after minutes to hours of running

#1

I am using the SmartMatrix SD shield v3 with my teensy 3.1 and I have broke three separate LED displays (2 32x32 and one 32x64) from Adafruit. Each display seems to work fine at first, but before too long, one or more quadrants goes bad. I will loose individual one or more colors to a complete 16x16 part of the screen. The rest of the screen seems to keep functioning. I am powering the display using an adjustable bench supply set to 5V. Here are some pictures of the first two boards. https://forums.adafruit.com/viewtopic.php?f=47&t=79397&p=404366&hilit=SmartMAtrix#p404366

I have no idea what could be causing these issues. The supply seems stable 5v (though maybe its spiking at random moments when I am not checking it). Could it be the SmartMatrix Shield? Should I be running it at 3.3V?

Seeing many are using these same LED displays here, I am hoping someone might have insight or similar experiences. Any help would be greatly appreciated!

#2

Sorry, this is the first I’ve heard of this problem. Three times is more than a coincidence, it has to be the power supply or shield. The panels are designed to run at 5V for both power and logic, so driving them at 3.3V shouldn’t be necessary.

By any chance does the display break when the SmartMatrix FeatureDemo example is on the brightness test? That drives almost all the LEDs on and at up 100% brightness so that’s a bit of a stress test on the power supply and panel. These panels can draw up to 3.5A (not 2A like Adafruit’s product description says). What is your power supply rated for, and do you have a current limit set on the supply?

Did you cut the VUSB trace on the Teensy before soldering? Did you verify it was cut with a meter?

Can you post pictures of the SmartMatrix Shield, both sides, on Adafruit? I’ve subscribed so I’ll get an email when it’s updated.

#3

Thanks for taking the time Louis.

  • The power supply is rated for 20 amps and I have it limit set at 5 amps right now.
  • I did cut the VUSB, but did not verify with a meter. Its difficult to verify with the meter soldered in. I was satisfied when the Teensy wont boot off USB power, only when powered externally. Is that enough of a test?
#4

Yeah, that’s a good test, I should probably update my documentation to say that’s sufficient.

#5

Thanks for all your help so far, in response to the Adafruit forums, I would be grateful for the additional help in verifying the board if I where to shipping it to you. Can you do private messages on this forum?

#6

Yes, I just sent you a private message, and you can click on any avatar and see a “message” button if you’re signed in.