Question PC not booting, just a buzzing sound from the motherboard ?

[thegreatbergo]

So I recently built a new gaming PC. A mITX. I am definitely not an expert when it comes to building PCs.
Everything was working perfectly fine until I decided to disconnect and unplug everything, to do a few adjustments and cable management and try out the new 4080 card.

I have now tried everything I can think of. Disconnect and reconnect cables (The front panel connectors always makes me doubt my abilities lol). Go back to the original GPU. Changing some of the cables from the PSU (I don’t have many extra). But the PC won’t boot or start up.
- No fans spinning
- No lights nothing
- Just a buzzing sound (barely audible!) from the motherboard when I turn on the PSU

I do a have a multimeter on hand, lack of PC(building) experience, but please help. Thanks!

Specs:
NR200p case
RTX 3070 aorus master
Cooler Master V850 SFX Gold PSU
Intel Core i7-12700K
ASUS ROG STRIX B660-I (LGA 1700, mITX, DDR5)

DDR5 16GB memory
M.2 PCIe 4.0 SSD

 

[Ralston18]

This PSU?

V850 PSU

Modular - did you swap in cables from any other PSUs or sources?

Use only the cables that came with the PSU.

 

[thegreatbergo]

This PSU?

V850 PSU

Modular - did you swap in cables from any other PSUs or sources?

Use only the cables that came with the PSU.

That is correct!

I did swap in a PCIe 5.0 12VPWR power cable for the GPU at one point. But now I’m pretty sure that I’m only using the standard cables.

 

[thegreatbergo]

That is correct!

I did swap in a PCIe 5.0 12VPWR power cable for the GPU at one point. But now I’m pretty sure that I’m only using the standard cables.

Just to clarify/details;
The buzz sound comes as soon as I turn on the PSU, but barely audible (“like you can hear some electricity to the board”). It continues until I turn off the PSU again. The power switch or any other buttons on the case doesn’t work.

the fan on the PSU doesn’t spin either..
and yes I have plugged in the main power cable..

 

[DaleH]

Just to clarify/details;
The buzz sound comes as soon as I turn on the PSU, but barely audible (“like you can hear some electricity to the board”). It continues until I turn off the PSU again. The power switch or any other buttons on the case doesn’t work.

the fan on the PSU doesn’t spin either..
and yes I have plugged in the main power cable..

Since you say you have a multimeter, you might find this site useful in troubleshooting the power supply: https://www.smpspowersupply.com/connectors-pinouts.html . However, the best test is to temporarily replace it with a known good one, if available.

 

[Ralston18]

Where is the buzz sound located?

You may be able to pinpoint the location by using a cardboard tube or rolled up sheet of paper to carefully "listen around" inside the computer case.

Find the source of the buzz.

Refer to the motherboard's User Guide/Manual for component locations - sort of map to describe where the sound originates.

And while you are at it, refer to the motherboard manual and the case manual to double check all of those case connections. They can be confusing so check all of them.

 

[thegreatbergo]

Since you say you have a multimeter, you might find this site useful in troubleshooting the power supply: https://www.smpspowersupply.com/connectors-pinouts.html . However, the best test is to temporarily replace it with a known good one, if available.

Thanks! I’ll give it a try! I don’t have a new one on the hand atm, but should be an relatively easy fix.
I do have some experience when it comes other electronics and somewhat a hobby electrician, but I’ll definitely check out some off the guides and be 100% sure before I even dare to poke around

 

[thegreatbergo]

Where is the buzz sound located?

You may be able to pinpoint the location by using a cardboard tube or rolled up sheet of paper to carefully "listen around" inside the computer case.

Find the source of the buzz.

Refer to the motherboard's User Guide/Manual for component locations - sort of map to describe where the sound originates.

And while you are at it, refer to the motherboard manual and the case manual to double check all of those case connections. They can be confusing so check all of them.

Thanks! I’ll try to locate the sound or the source.

Ive checked the manual multiple times, it’s lacking details to be honest.
I will keep trying

 

[thegreatbergo]

Is it safe to jump start newer power supplies these days? And would that really give me any indications?