One of the primary color is absent

If your LCD TV or monitor has stopped working, or is displaying one of the following symptoms, then it's a candidate for some new capacitors
- Flickering screen
- Screen image disappears after several seconds
- Dim screen
- Slow start
- Power LED on, but no picture
- Unusual colors and/or lines
The primary cause of LCD TV and monitor failure is caused by faulty capacitors. You can examine the capacitors in your LCD TV or monitor and actually see if they are bad.
If they appear bulged on top, then they need to be replaced.
New capacitors will solve a host of problems in LCD monitors and TV's and will extend the life of your monitor or TV by several years.
Check the cables, connectors and connections.
Take it to a repair shop.
https://www.youtube.com/watch?v=TR2iWN6b-LY
LCD TV Repair No Power Power Supply Common Symptoms Solutions How to...

The red "gun" of your CRT monitor is going bad. You will need to get a new monitor, and you should seriously consider an LCD flat screen. It will save you allot in electricity.

A CRT monitor is a very cool piece of technology inside... even though they are going obsolete with the advent of modern LCD displays.

In every CRT (Cathode Ray Tube) monitor, there is a trio of "Electron Guns"- they fire electrons at the front of the screen, hitting it with billions upon billions of electrons... the "bullets". Each gun is aimed at a set of colored targets, called "pixels"... one gun hits red ones, one for green, and one for blue. Combinations of these colors make up everything we can see.

When the red "gun" cannot fire enough electron "bullets" at the screen, the blue and green together make the picture appear yellowish.

If you want to learn more, look up "cathode ray tube" on wikipedia for starters!

A word of warning- the technology is very cool (I used to teach how CRT screens worked as part of my job teaching Missile fire control radar for the Navy), BUT:

THERE ARE VERY HIGH VOLTAGES INSIDE A CRT MONITOR THAT CAN KILL!!! DO NOT OPEN
THE CASE!!!!

Remember- the electron "guns" inside are shooting billions and billions of electrons at the front of the screen. They are being collected from the screen by a high voltage "supply". Most CRT's operate with anywhere from 15 to 45 THOUSAND VOLTS!

problem with the monitor Display cable. it is damaged.

Normally monitor will receive 3 colors red, green, Blue signals from CPU. If one cable i.e Red wire connection is missing in display cable which is connected to monitor, Red color image on monitor wil be replaced with other fade color.
So, need the replace the display cable or display connector!

This usually means the red or green or both primary color module is bad. Monitors come with 3 primary color module controllers and they use them in various combinations to make the other colors. The primary colors are blue, green, and red.

CRTs use 3 "guns" to mix the 3 "primary" colours (RED, BLUE, GREEN). One of the other guns has stopped working, leaving the RED gun as the "dominant" colour.

Spend $30, and buy a pre-owned 15" LCD monitor.
Or, spend $100, and buy a new 17" LCD monitor.

Possibilities:
1. video-card gone bad;
2. video-cable gone bad;
3. video-cable not tightly-connected to CRT;
4. video-cable not tightly-connected to video-card;
5. "red" gun inside CRT gone bad.

Disconnect the video-cable from the computer, and try again to adjust the "red". If red-free, then it's time to responsibly recycle the CRT.

Reconnect & wiggle the video-cable, to see if that induces any "red" onto the CRT.

Connect the CRT to the VGA-output port on a notebook computer, to see if that video-card generates "red" as one of the primary colours.

Give the CRT a strong "whack" on the side, to see if "red" makes an appearance.

One or two of your color guns are failing. On a CRT, there are three color guns, Red, Green, Blue. They work together to produce all colors in the spectrum. If the monitor goes all one color, it generally means at least one color gun is failing. The cost to repair far exceeds the value of the monitor or the price of a new LCD panel.

Red color gun has failed, which will make the picture over saturated with the other two colors(blue,green) the bad news is the three color guns need to be replace in a set(all at the same time) because if you only replace the red it will over saturate the older blue, green guns then your picture will be mostly red.Unfortunently in most cases it's not worth the investment, better off to purchase a new tv. Good luck !

Your monitor has a menu system that will allow you to access the color guns so you can adjust the red, blue, green guns that create the color picture.

The blue tint may indicate that you need to adjust teh reg and green to offset OR it may indicate that you have lost the red gun all together.

If this is an older monitor and you are considering repair... cost points say it is cheaper to buy a monitor ~$60 bucks

it is very simple, by default in monitor circuit RGB (Red, Green, Blue) tube is installed. and in combination of both of three colors we are able to view colorful image. due to non functionalty of Red color u r not able to view red color in screen, either you replace picture tube or purchase new monitor. coz cost of this tube is equal to monitor.