Just modded

A project log for RGB LED Backlit Mod

Willing to make better color gamut?

Thomas Chanon WangtriratThomas Chanon Wangtrirat 12/07/2015 at 18:340 Comments

Hi! guys. Some long time before initial modification of my beloved NEC Multisync 2090uxi. As you know this monitor is sRGB monitor in color critical section. The panel is extremely good opposed to the age of it from year 2006.

Last time I testing the High-Voltage driven RGB-LED strings which rated nearly 280V so I drive it with Opple 9W LED Driver which drive just that same High-Voltage array of White-LED.

Rated at 9W is enough for all purposed here!!! Runs cool and great.

I made some platform for assemble the LEDs chip together by using 2 rulers and some electrical tape as adhesive when in sit on matte cut sheet. After arranging LED in series together I put some flux on it to prevent solder lead being melt stick together. I have to did it 2 times per string. So 8 times of this string made.

The control circuit is straight forward. If you connecting Red LED to Blue and Green it will draw all current to it because it have lower voltage. So I drive PWM to MOSFET (in this case I chose IRF840) via opto-coupler and signal from Arduino running RGB Control.

The code is somewhat vary easy.

#define GREEN 9

#define BLUE 10

#define RED 8

void setup() {


pinMode(BLUE, OUTPUT);

pinMode(RED, OUTPUT);

digitalWrite(GREEN, HIGH);

digitalWrite(BLUE, HIGH);

digitalWrite(RED, HIGH);


int redVal;

int blueVal;

int greenVal;

void loop() {

int redVal = 0;

int blueVal = 0;

int greenVal = 0;

analogWrite( RED, 255);

analogWrite( GREEN, 58);

analogWrite( BLUE, 86);


The values vary from how it will be drive in most case.

The NEC Multisync 2090UXi used 3 CCFLs per side of Light guide. the width of it can be fitted with 2 strings of RGB-LED snuggled.

The result from it is Stunning!!!! I select Native Color profile and adjust RGB value to matched 6500K

Of course when use wide-gamut monitor you have to calibrate it. If you don't but just for fun just loaded Samsung XL20 ICC profile here Samsung SyncMaster XL20 to make it display sRGB content nearly correctly and it's extremely Wide-Gamut even 5K iMac P3 gamut can't be matched.