My monitor is gettig off after flikring,means brightnes becomes less and then is goes off???? and when it is run only on power suply it runs normal!!! wat is the problem

wow a real computers question
but no PC stated. make nor model.
desktop or laptop
what OS do you run.
if a laptop,(why must I guess?)
ALL or most laptops dime for these reasons. (all)
1: the room is dark and the auto dim is turned on.
2: the laptop battery is bad or weak and it auto dims the screen to extend the run time, dim uses less power.
3: the LCD is dimmed in the control panel ."brightness wrong"
4: the LCD back lamps on all PC <=2010 all are dim now.
both monitors and laptops that old or older, are doomed.
<= means less than or equal to....

this souinde like your power suply switch is turned off. if you look on the back of your computer were the power cord goes into the computer thats your power suply. if you look closly there is a switch on there this switch proble got shut off. you wanna make sure it is turned on.

Alternator
When the battery light is on the truck is running off the battery when the battery looses juice the truck will shut off

Hope this helps, it it does please leave feedback Thank You and Good Luck

CHECK FOR DAMAGED RESISTORS ON BOARD NEAR HIGH VOLTAGE AND ALSO ON CRT SOCKET, ITS A COMPONENT PROBLEM, RECTIFY IT..CHANGE THE DAMAGED COMPONENT, ALSO CAPACITORS IF POSSIBLE..

what happend is your monitor cought the brown out and the power supply capcitors are not defective and what that means is the monitor needs to be repaired there is no quick fix please rate accordenly thanks.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/edwy_1a56970cf1ea4620

I flashes brightly over and over? Sounds like the Power Supply is gone or on the way out. This is caused by the Power Switch Transistor being too loosly clamped to heatsink allowing it to become too hot, or one of the capacitors responsible for filtering or frequency of oscillation is drying up and changing value. A good tech can fix either. Most likely the filter cap and AC (60hz) is getting thru. This is a $3.00 part

Or the inverter in the LCD is biting the bullet. If you turn down the brightness, does it stop or do it less often? THAT would be the invverter. Inverters take 5, 12 or 24v from the mainboard and run the itty-***** pencil-sized florescent lamps that light up your screen. Lamps are $8.00 and inverters can be $50-80, but ebay has them for alot less

Hopes that helps

maybe your cpu is faulty or ... maybe power suply ??

Hi, sandjkroll, this kind of problem could be because of ur monitor or even because of the on board display  card on ur motherboard. To check ur monitor, u unplg display cable which goes to ur cpu and the power cable which goes to ur cpu. 
Them connect the power plug to mains, so no cable from the monitor should go to the CPU. Then u swithch on the the poower suply, and on the monitor. I
If ur monitor displays elongated screen still, and shows signal not found,and no display comes that means ur monitor needs to be send for service. and if there are no elongated screen and says no signal found, ur monitors fine, ur motherboad has a problem

From
Deepak

From the mains?

You mean power?

If you have to uninstall the display controller , that means that your video drivers are bad, and you are running the native video drivers.
Get new updated drivers and keep us posted.

as your power supply is ok check hor. section if it becomes ok you will get voltage on g1 &g2.