The computer does not start (no signal on the monitor)?

Question

Do it yourself

I bought a new motherboard (H81M-s1), and a new video card.
I assembled the computer, and oops, it shows no signs of life. began to sin on the power button (the old processor, RAM and other "peripherals" workers) went to Google, they told me to close the contacts on the motherboard
reset switch (res + and res-). The computer showed no signs of life. but then it turned out that when the res- and pw + contacts are closed, the computer starts to do something, or rather, the coolers on the motherboard and video card make noise. The monitor also wrote "Check Signal cable" (no signal). put the old video card, the result is the same. There was advice on the Internet for a similar problem - resetting the BIOS by pulling out the battery - it did not help.
The power supply is also new, the monitor is working, the cord to the monitor is working

Answer 1

Look for the POST card for diagnostics.
Connect the speaker.
Is the processor correct? Exactly compatible with the board?
Memory pulled out / changed?
Is the power supply pulling?

Answer 2

What does this board have in the BIOS about video priority? Maybe it works on the built-in card? If there is such an option, put the first external video. Here:
Peripherals - Initial Display Output - PCIe
Although it is written that this should be the default ...
Well, anyway, without an external video card, first check the board.

Answer 3

If the power went to the mother - the coolers were noisy - and the video did not appear, there is an option that the percent did not start. This may be due to the following reasons:
- defective processor
- processor is installed incorrectly
- when installing the mother, there is a short circuit to the case somewhere
- the power cables to the mother are connected incorrectly or one of them is not connected
Take out the memory and try to start it - the speaker should beep. If not, remove the cooler and run it for a few seconds by touching it with your finger. If it does not start to warm up, the percent is probably faulty. Two or three seconds will not burn the percent.

Answer 4

I've had something similar over and over again. It is solved like this:
1. Table test. The motherboard is removed from the case and placed on an insulating surface (wooden, for example).
2. All cables are disconnected, except for the minimum required: Power, CPU Power, Display.
3. All devices are turned off, except for the minimum necessary ones (that is, remove the vidyuhu).
4. Optional: You can also turn off the front panel and turn it on by contact closure.
Well, further on the situation to increase the complexity.