DmxSimple > MAX485 > DMX LIght Not Working

Have an Arduino Uno with DmxSimple library, digital pin 1 to a Max485 to a DMX light.

MAX485 is on a protoboard about 2" from the Uno and is powered from the Uno's 5V pin. MAX485 power pin has 10uF and 0.1uF caps to Gnd. Twisted pair (~2") from digital pin 1 to MAX input pin 4. Twisted pair (~2") from MAX output pins 5, 6, 7 to DMX XLR connector. Followed the XLR pin numbering per the circuit below. 25' DMX cable from connector to DMX light. DMX light has terminator installed. DMX light address set to "1" and configured tor 3CHAN operation.

Used the following circuit:

http://playground.arduino.cc//DMX/DMXShield

and this code:

void setup() {
    /* Do init stuff here */
  Serial.begin(9600); // Initialize the connection to Serial Monitor
//  randomSeed(analogRead(0)); // Pick a random seed
  
  // DMX output on digital pin 1 (Tx).
//  pinMode(1, OUTPUT);
  DmxSimple.usePin(1); 
  DmxSimple.maxChannel(3); // Max channel for a single PiX Mini is 18
}

void loop() {
    
 int mode;   

//     DmxSimple.write(1, 255);    // red
//       Serial.println("Setting color to RED" );
//     delay(100);
     DmxSimple.write(2, 255);  // green
       Serial.println("Setting color to GREEN" );
     delay(100);
//     DmxSimple.write(3, 255);   // blue
//       Serial.println("Setting color to BLUE" ); 
//     delay(100);
  
} // End Loop

Commented "pin mode" since didn't seem to matter and I'm guessing the DMX library sets the pin mode.

I get nothing from the light other than a few flickers and solid red only when I first plug in the Uno to USB. I do see the serial print messages in Serial Monitor. Commented red and blue hoping to just get green. On a scope the signals look as I'd expect. The "signal" pin is 0-5V pulses and the "signal inv" is 5-0V. Saw some other DMX circuits with terminating resistors so added a 120 Ohm across pins 6 and 7 but no change.

A few things I plan to try... Set all 512 channels so I can better see the waveforms on the scope. Add a separate 5V regulator instead of using Uno 5V. Switch the wiring polarity of "signal" and "signal inv" (The light's troubleshooting section suggests this.)

I know the lights respond to DMX signals because I slaved one to the other and it output the same pattern as the master. Even if signal quality from the MAX485 is not ideal should I at least get something from the light?

  Serial.begin(9600); // Initialize the connection to Serial Monitor
  DmxSimple.usePin(1);

The serial interface uses pin 1 as it's TX pin. You cannot use that pin for your serial debugging and for the DMX communication.

Exactly correct! I forgot that the Serial.print was using that port also. Changed DMX output pins and works great now!