Monitor doesn't gets on

[ardilatif17]

Hi, whenever I turn on my CPU it starts beeping. It beeps 4 times after every 2 seconds. And the monitor doesn't gets any signal.
It's a custom built CPU and I've got no motherboard manual.

 

[mdd1963]

Do you know what kind of motherboard you have? The beep sequences of failure codes (3 beeps, 6 beeps, etc., can often be referenced in your MB's manual for info.....

However, some more info would be helpful (In fact, any info would be helpful)

Has this system ever worked before, or is it a new build, for instance?

 

[gingerrankin]

look at:

https://www.computerhope.com/beep.htm