Monitor displays "no signal" when powered on.

you may try this came from manual.
Power Management" "countdown 20 sec
INPUT SIGNAL OUT OF RANGE
This OSD may appear to inform you that the signal being sent to the display is not within its frequency range. In this case, you would need to check the resolution and refresh rate you have your video card set to, and adjust to be within the range of the display

Check signal cable means that your monitor wire is not connected properly.
So remove your cable connect it tightly once again.
Tightly connect with cpu and power supply.
Thanks for using fixya

it sounds like a problem with the firmware.

Monitor is not getting a signal from the computer. Ensure the cable connections are correct. If the monitor has a input select option, ensure it is set for the cable option selected.
If tower is a Dell, ensure the power LED on the Tower is Green/Blue If flashing Amber, power supply may have failed, solid amber, motherboard or a device connected to it may have failed.
http://www.fixya.com/support/r4282412-find_no_post_diagnostic_information_dell

disconnect the signal cable and power on then see the massege on monitors screen "NO SIGNAL CHECK THE SIGNAL CABLE"if it appears then monitor is ok if not then monitor is faulty check the signal cable and replace it if faulty problem will be solved

This indicates either a problem with the monitor cable(ie shorted) or the display adapter. Try plugging the monitor into a different computer and if it works you will need to install a new display adapter in your computer. If it doewn't work on the new one either you can try a different monitor cable if yours isn't permanently connected. Hope this helps

yes please take the power on self test means disconnect signal cable and monitor will give
display without cpu if display appears then monitor ok fault is in cpu if not then fault is in monitor move signal cable and look display changes or not if changes then cable faulty replace it

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

Most monitors will say "Power save mode" when they can tell through residual voltage that the signal lead is plugged into a machine, but there's no picture being transmitted. The four states of a monitor are:

* Off entirely.
* Switched on, plugged into a computer but no video signal being received - usually displays "analog power save mode" or "digital power save mode" for a few seconds, then blanks. Comes back to life the moment a video signal is received. This state is the default in full power saving mode.
* Switched on, not plugged into a computer. Some monitors don't display anything, some go into power saving mode, some fly "CHECK SIGNAL CABLE" or a similar message around the screen. Picture is restored when the signal cable is plugged back into the computer
* On fully, receiving an image, and displaying.

Hope this helps.

I think is a power supply problem,,