After Cold Start, Corsair AX850 won’t turn on immediately

I have installed the Corsair AX850 850W on my computer. This is working good when I use that continuously but when I cold start my computer then it become problematic to start the system for a few minutes. If I disconnect the system from the power socket and keep that as it is for, ets say 1 hour. After that when I connect that back to the socket and try to boot the system then it failed to boot. I have to wait for 10 to 20 minutes in order to start the system. After about 20 minutes when I click on the power button on the PSU then it starts the system normally. It didn’t show any problem like this when I turn off the computer and start that immediately.

I think that the PSU that you are using is faulty and so it is showing you this weird behavior. To confirm this, just open the case so that you can observe the motherboard. Now connect the power and switch it on. Don’t turn on the computer. If the PSU is working well then you must get a green light on the motherboard and if you are not getting the green light on the motherboard then PSU is faulty. As you said that you can boot the system after 10 to 20 minutes then I am sure that you will get the green light after 20 minutes only.

There is one setting into the BIOS where it checks for the CPU temperature before it starts the system. This is known as the "Health Check". This is recommended setting but if you are facing problem with the setting then you can try by setting this to false. I hope you know how to get into the BIOS save the changes to it. Try and let us know if this was helpful to you or not.

When you updated your BIOS last time? If it’s too long that you updated your BIOS then it is outdated. Other than this, it might also be corrupted. Whatever the reason, but it is worth to try by updating the BIOS to the latest BIOS. You can visit the motherboard manufacturer site and from there you will be able to update the BIOS. In case, you have already updated the BIOS to the latest then you can try by flashing the BIOS. You must take the backup for the important data because there is always a chance of losing data when you flash the BIOS. I hope this will be helpful for you.

I am not very sure about this but if you want then you can also by clearing the CMOS. Below are the steps to do that.

1. First of all, you will have to detach the main AC power supply from the board so that there is no power supply to the system. After removing AC power supply, keep that as it is for about 3-5 minutes. This will ensure that all the capacitors and coils are discharged. If you want to discharge that immediately then you can also press the power button on your computer.
2. Now, you will have to shift the CMOS jumper on the clear position. You can read the manual of the motherboard you are using and you will get the way to do it from the manual.
3. After a few minutes the CMOS will be cleared. So after a few minutes , you have to put back the jumper into the original position. You can connect the power supply now.
4. Check, if that shows you the same problem.

The above mentioned steps are correct but for some users that is a bit confusing. I have a very simple method to do this which does not require anything especial to do. Just disconnect system from the power socket and let the capacitor and coils to be discharged as already mentioned in the above steps. After this, take-out the CMOS battery from the board and let it be out for at least half an hour. After that, insert that back into the board. See if it again takes long time to start the system when cold start. Other than this, if you have not changed the CMOS battery from a long time then it is also recommended to change the battery with a new one. Good Luck!!!

Have you installed any hardware to your computer recently after which you started with the issue? It is possible that the PSU that you are using is not able to handle that hardware as that might require more power to start. So, your PSU might be dying and this is the time to change that with a new one and make sure that it supplies sufficient power to handle the hardware attached to it.

Other than this, you must notice that if you are getting any beeping noise when your computer is not starting. Normally beeping noise from the motherboard indicates problem with RAM. That can be either with the RAM connection or RAM module itself. You can try by resetting the RAM modules and switching the RAM slots.

There could be many reasons for this behavior and some of them are already posted above. There are a few possible reasons for the problem that I am listing here. See if any of that is true in your case.

• You must also check that if the power for the switch header and hardware reset switch header are connected with the correct connector's.
• If you are having poor motherboard bios chip. So in that case, you must contact to the vendor they will replace the BIOS chip.