8x8 led matrices failure mode

Other Hardware LEDs and Multiplexing
1

Hi,

I was working with a display made up with 4 8x8 led matrices (MAX7219), out of nowhere the last (counting from the wire input) started acting up, it didn't initialize when the mcu was reset and stay all off or all on, if I pressed it (gently) while reseting the mcu it started ok and worked for some time, this time started getting shorter, from days working ok to a few seconds.

Like this one: MAX7219 Dot LED Matrix MCU Control 4-in-1 LED Display Module for Arduino AU for sale online | eBay

As the matrices were in sockets I assumed that it could be a bad contact, I removed the sockets and soldered the matrices directly on the board (unfortunately ripping one pad on one of the modules, it was not easy to unsolder the sockets), more, I removed the jumpers connecting each board to the next and soldered a wire across each pin.
Unfortunately, this did not solve the problem, the matrix in the 4th board (not the same matrix module) still have show the same problem, and still works for a few seconds if I press it while reseting the mcu.

The mcu is a ESP01-S module and the lib is md_max72xx + md_parola.
The matrices are powered from a breaboard power supply at 3.3V, not from the ESP01-S. The ESP module is being powered from the programmer/breadboard adapter (GNDs are connected between the matrices and the ESP).

The programmer/breadboard adapter is this one:

https://www.ebay.com/itm/323127795519

Any idea what could be causing this ? I can understand if it works or not, this "getting worst" (I mean, works for less and less time) makes me mad, bad contacts are rolled out, I even re-flowed the contacts in each MAX7219 chip.
I could understand if the ESP01-S did not have the "power" to "reach" the 4th module, but once again it should work or not and not start working for less and less time.

I'll not be using this board any more, but I'd like to know if this is something to be expected from the Chinese boards and/or MAX7219 and/or led matrices.

2

A few things to try:

  1. Make sure you have the latest libraries for MD_Parola and MD_MAX72xx as there were some issues with multi-zone displays a few months ago.
  2. Try a different library (like LEDControl) and see if the displays work (even if the are displaying backwards or upside down).
  3. Check the wires between the MCU and the display. These are often the problem.
  4. Try using a different set of matrices (looks like this is happening).
  5. Try using a different MCU, something like an Uno.

If any of these things make a difference then the thing that was eliminated from the original setup was part of the cause for the failure.

It could also be a dud set of matrices, although that is rare in my experience.

3

Libs,, MD_Parola is 2.7.4 is up to date and MD_MAX72xx is 2.10.0 witch is not the last version, I don't know why Arduino IDE is not detecting 2.11.1.

Got it working.
Instead of feeding the matrices 3.3V I'm now feeding 5V and it's working... so far.
I'm wandering if I need a level converter between the ESP-01 and the leds.