Charlieplex Issue

I have 4 16x9 charlieplex drivers and displays (all from adafruit). I assembled them all and tested them all with the example sketch.

I then soldered the the addresses, so that each one is different. And wired them in parallel VIN and GND are to 2A 5v source, SLC and SDA are to the A4 and A5 on an Arduino.

I then ran this code:

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_IS31FL3731.h>

Adafruit_IS31FL3731 quadMatrix[4] = Adafruit_IS31FL3731();

const byte Height = 9;
const byte Width = 16;

void setup() {
  Serial.println("Orion Mk2 Plex1");
  for(byte m = 0, i = 0x74; m < 4; m++, i++)
	if(! quadMatrix[m].begin(i)){
			Serial.print("No ");
			while (1);
	Serial.print("Yes ");

    for(byte q = 0; q < 4; q++) {
                quadMatrix[q].drawPixel(0, 0, 255);  

void loop() {

I get a yes for all four on the serial monitor, but I can’t get any pixels to light up. Am I missing something simple?

Did you try one of the example sketches that comes with the library? Set it for each of the 4 addresses in turn, to test each of the 4 displays separately. Do they all work?