8x8 led matrices failure mode

Other Hardware LEDs and Multiplexing
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.