Question What is the most likely cause of no beep during boot phase?

[jttraverse]

I'm debugging a system with an Asrock x399 Phantom Gaming 6 motherboard and an AMD Threadripper x1950 CPU. As of a few days ago, even though the lights and fans turn on as expected, it never 'beeps' or shows anything during POST, and the monitor acts as if it gets no video signal (black screen).

I've tried unplugging everything there is to unplug to see if I could get any difference when powering on. So far nothing. There is power coming from the PSU, at least the fans and lights all come on and I can tell the CPU begins to warm up. Past experience would make me think that even with no RAM installed it should still at least POST/beep. The same with having no drives installed. (Some of the things I have and haven't yet tried are down below.)

So I'm curious what the most likely culprit would be if you don't even get the beep during the POST phase??
Would that usually indicate the MB is at fault?
Would a bad CPU effect the BIOS post/beep?
Even if the CPU is bad, with a known good graphics card wouldn't you still see something on screen even if just error codes?

Any ideas will be appreciated,
JT

So far...
**I've verified that the graphics card and is working. That said, I've read that the CPU communicates with the GPU, so if the CPU is dead would the MB not even see the graphics card during POST?
(This MB apparently requires the CPU to be installed and screwed down to even power on, so I can't leave the CPU out and test the MB alone.)
**I intend to try a different PSU asap on the chance something is wrong with the power voltages, etc.
**I don't have an extra CPU or motherboard to test with just yet, and haven't been able to check the RAM yet either (32gb Corsair)

 

[kanewolf]

I'm debugging a system with an Asrock x399 Phantom Gaming 6 motherboard and an AMD Threadripper x1950 CPU. As of a few days ago, even though the lights and fans turn on as expected, it never 'beeps' or shows anything during POST, and the monitor acts as if it gets no video signal (black screen).

I've tried unplugging everything there is to unplug to see if I could get any difference when powering on. So far nothing. There is power coming from the PSU, at least the fans and lights all come on and I can tell the CPU begins to warm up. Past experience would make me think that even with no RAM installed it should still at least POST/beep. The same with having no drives installed. (Some of the things I have and haven't yet tried are down below.)

So I'm curious what the most likely culprit would be if you don't even get the beep during the POST phase??
Would that usually indicate the MB is at fault?
Would a bad CPU effect the BIOS post/beep?
Even if the CPU is bad, with a known good graphics card wouldn't you still see something on screen even if just error codes?

Any ideas will be appreciated,
JT

So far...
**I've verified that the graphics card and is working. That said, I've read that the CPU communicates with the GPU, so if the CPU is dead would the MB not even see the graphics card during POST?
(This MB apparently requires the CPU to be installed and screwed down to even power on, so I can't leave the CPU out and test the MB alone.)
**I intend to try a different PSU asap on the chance something is wrong with the power voltages, etc.
**I don't have an extra CPU or motherboard to test with just yet, and haven't been able to check the RAM yet either (32gb Corsair)

First thing is that most cases don't have a speaker to connect to the motherboard.

 

[jttraverse]

Ha..fair enough and I should have said so. I do have the small two-wire speaker plugged in (and it's always worked in the past..fwiw)

 

[drea.drechsler]

Ha..fair enough and I should have said so. I do have the small two-wire speaker plugged in (and it's always worked in the past..fwiw)

That does complicate things since a CPU or GPU failing in POST should result in the system generating some BEEP codes through the system speaker you have installed.

Does your motherboard have any trouble shooting LED's? They usually leave only one lit if something fails in POST. Check your manual to see what it means.

When you start up is the drive LED(s) blinking as though the OS is booting? It's possible to set up many BIOS for a no-display configuration. So no beeps or trouble shooting LED's will be lit even if something's wrong in the GPU.

Your motherboard has more than one PCIe x 16 slot...try plugging the GPU in a different one. The top slot is doubtless connected to the CPU with the lower ones are probably connected to the chipset. So if something's wrong with the CPU data feed to the GPU this might bypass that.

Try re-setting CMOS.

And lastly: check your monitor. Those things can also fail.