Problem with the led matrix

Official Hardware Classic UNO R4 WiFi
1

Hi,
one of my Arduino Uno R4 Wifi does not light up two leds of the matrix.

Using the following sketch I found that the LEDs (5,5) and (5,6) do not work correctly. The first value is the row, the second parameter is the column. I thought that the leds are faulty.

void allPixelsOn() {
  const uint32_t frame[] = {
    0xffffffff,
    0xffffffff,
    0xffffffff
  };
  matrix.loadFrame(frame);
}

void setup() {
  allPixelsOn();
}

Testing another sketch I found that in some cases more than only one led lights up. This must be wrong because the sketch controls only one of them.

void blinkPixel(int row, int col, int millisec) {
  uint8_t frame[8][12] = {
    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
  };
  frame[row][col] = 1;  // led on
  matrix.renderBitmap(frame, 8, 12);
  delay(millisec); 
  frame[row][col] = 0;  // led off
  matrix.renderBitmap(frame, 8, 12);
  delay(5);
 }

void loop() {
  // put your main code here, to run repeatedly:
  for (int r = 0; r < 8; r++) {
    for (int c = 0; c < 12; c++) {
      blinkPixel(r, c, 100);
    }
  }
  delay(1000);

  for (int c = 0; c < 12; c++) {
    for (int r = 0; r < 8; r++) {
      blinkPixel(r, c, 100);
    }
  }
  delay(1000);
}

Is there a firmware that controls the matrix? Could it be that this firmware must get a new version?

2

*first, physically examine the two LEDs for solder bridges or backwards installation.

NEXT, Use a multimeter in "diode" setting and test the two LEDs in both directions. One direction should light the LEDs. Compare results to a few "good" LEDs.

3

Post an annotated schematic of your project, I cannot see a thing. Show all connections, power sources and links to technical information on hardware items. I am fairly sure it is a hardware problem. Also list the LED colors.