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: https://www.ebay.com/itm/263524861449
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:
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.