Question My motherboard doesn't work: it doesn't even beep at startup

[rd1066_2]

Hello folk,
My PC has a GIGABYTE GA-MA770T-UD3P motherboard and a AMD Sempron 145 CPU
4gb of RAM
Graphic card: Rx470

It just stopped working all of a sudden...

I removed the graphic card and all other peripherals (keyboards, mouse etc..). The goal was to diagnose
throught the beeps


So this is the problem:
when I turn on the PC, these things happen:

-The CPU cooler fan start running but nothing else seems to work
-the motherboard doesn't beep at all... instead the speaker (after some seconds) makes a brief strange damped
"noise" that could be simply caused by the fact that the speaker get "powered on" .... This strange sound is
like a damped short very soft noisy "beep" almost imperceptible and may be nothing strange but simply
caused by powering on the speaker (it is similar to the sound you hear when you turn on a radio).. so it
may be totally normal.... but it is the only sound I can hear from the speaker...

These are some things that I have noticed:

-When the PC is turned off, the USB ports are correctely powered on (devices attached to USB ports can be charged)
this is normal behaviour so it proves that motherboard isn't completely fried

-the power led works.
-the CPU cooler fan start spinning as soon as I turn on the PC
-If I keep pressed the POWER button for 5 seconds when the PC is turned on, nothing happens (on the contrary
when PC was working, keeping pressed the power button for 5 seconds would have turned it off instantly..)

these are further behaviours that may be useful to diagnose the problem:

-If I remove the RAM modules.... nothing changes.... If the PC was healthy it should have given some "memory error" beeps... but nothing is beeping....
so my idea is that there's something serious happening before the motherboard start checking the RAM

-If I remove the CMOS battery.. nothing changes...

-if I remove the CPU.... the speaker doesn't do that strange damped noise anymore... (all rest remain the same..
CPU cooler fan still spinning.. etc..).. this is quite interesting: it shows that CPU may work properly....


Other things I have tried:
-I tried using a different PSU.... nothing changes (so I think the problem is not the PSU)....


Does anyone have an idea of what could be the problem?

Thank you very much

 

[thx1138v2]

Ensure your speaker is connected to the F_Panel connector properly. If it is and you still don't get beeps, it's likely the motherboard is toast. You can probably get another one from eBay relatively cheap or it will be time for a new build.

If you do get beeps, follow the diagnostics to fix your problem.

 

[rd1066_2]

I tried connecting a different speaker (that I'm 100% sure is working).....
and the behaviour is the same as always: you can hear just a sort of "click" on the speaker few seconds after the system starts up,
but no beeps at all.......

 

[rd1066_2]

As a side note, I'd like to add the fact that the CPU cooler fan spins at an unusually "slow" speed... the PSU fan doesn't even start at all...
I have this "feeling" that there may be some sort of power issue, like the motherboard doesn't get properly powered in some way...
Again, I'm sure it is not a a PSU fault (I've tested the motherboard with a different working PSU and the result is the same)
Also the hypothesis of an undervoltage problem could explain why the speaker emits just a weak "click" noise instead of beeping...

 

[rd1066_2]

I removed the RAM and tried again: nothing changed... still no clear "beep" at startup

 

[rd1066_2]

Absolutely good news!! The motherboard is working again!
I dismantled everything and took the motheboard out of the pc case: I put it on a glass surface... reconnected everything and.. it JFWed !!!
I 'm having now a real hard time figuring out what the heck was going wrong....
Maybe some short circuit with the case somewhere? Maybe some faulty connection caused by dust? Who knows.....

So my problem is solved, thanks everyone for your help!