My monitor fade sometimes.What could be the problem?

Answer:

the monitor may be going discouraging, either that or the video card, but most expected the monitor
power supplier?

display card?

monitor?

motherboard?

all the reason above can cause
It could be voltage problem, loose contact beside electric socket or the diode/capacitor/transistor in the picture tube is not performing. Its a minor issue.
power supply is the proble. the voltage is low else ur monitor is destabilized
mab your crt's picture tube is malfunctioning
The problem comes due to the capacitors will get heated contained by the monitor that is the common sense it will fade some times and you can also some heat smell also at that time what you can do show it some of the monitor reparing service focal point.
THIS IS CAUSED BY A STRONG MAGNET COME NEAR TO UR MONITER.GO AND REPAIRED IN UR NEAREST SERVICE STATION.
your computer is very dated or your monitor.