Question My 10-year old PC won't boot ?

[Ancipital]

Hi.
Some weeks ago, my beloved 10 years old PC went belly up 😥.

When I press the power button, the video card cooler start spinning, but I hear no POST beep and I see no image on the screen.
The CPU gets mildly warm, but it might overheat if let running more than a few minutes without radiator so I let the radiator on it (no fan).
There is no chip overheating - I "fingered" all of them , I looked also through a cheap thermal camera.
Not a single LED lights up.

Power supply
I measured the power on all pins. It is all fine except the negative 12V rail, which is 11.18V (but this is still well within its 10% margin).
At least the main board answers to the power button. I can start the computer, and if I keep the power btn pressed for 4 seconds, it also turns off the power supply PC.
The pin 8 (PowerGood) is +4.1V - I don't know if this is its good value...

BIOS/CMOS
Trying to clear CMOS, also nothing. The second BIOS won't kick in.
I heard there is a trick you could force the backup BIOS chip kick in. Something like keeping the reset and pwr buttons pressed for 10 seconds while turning on the power supply.

Any ideas? Any hints?
Please help a sad guy....

 

[rgd1101]

full system spec? include brand and model of the psu

 

[Ancipital]

full system spec? include brand and model of the psu

The system is (was):
GA-990FXA-UD3 (rev. 3.0) DualBios https://www.gigabyte.com/Motherboard/GA-990FXA-UD3-rev-30/support#support-dl-bios
AMD FX-8350 4GHz
32GB RAM
PSU Antec 750W
All capacitors are ok. None look swollen.
__
I tried to force the backup BIOS to kick in:
Keeping the reset and pwr buttons pressed for 10 seconds while turning on the power supply.
Keeping the power btn pressed to 10 seconds.
Keeping the power btn pressed while turning on the power supply and then imediatelly shutting it down.

 

[Ancipital]

I changed the battery.
Nothing changed.

 

[DSzymborski]

What's the model of Antec? Antec is the brand, 750W is the wattage.

I would suspect the motherboard has given up the ghost, but if it's a lower quality Antec, it might be the PSU still.

 

[Ancipital]

but if it's a lower quality Antec, it might be the PSU still.

But all voltages are there. I measured them one by one.

 

[rgd1101]

if it is not the psu. then get another motherboard for testing

 

[DSzymborski]

But all voltages are there. I measured them one by one.

That's not how it works. You're measuring with no load on it. Those PSU testers can only verify basic functionality. The cheapest garbage can get within the +12V ATX spec with nothing running on it. There's a good reason proper load testers costs in the thousands while you can get a PSU tester or a multimeter for $15.

We still don't know if your PSU is working or even what your PSU is. Without this information, there's nowhere farther to go.

 

[Ancipital]

I measured the clock on pin 6 on the BIOS chip. It is 0V. It looks like the clock generator is dead.

PS: after the first mainboard died, I purchased a used one (pretty expensive). It died 1 year later in the exactly same way.
So, I am somehow afraid to reuse the PSU. Maybe it killed the mobo?

 

[lava2]

bad RAM. In this case

 

[ex_bubblehead]

bad RAM. In this case

And how do you know this?

 

[JohnBonhamsGhost]

I am somehow afraid to reuse the PSU. Maybe it killed the mobo?

Antec has distributed a wide range of units.
some good quality, some very bad quality.

without the specific model, no one can gauge the probability of it possibly damaging connected components.

if you don't have a backup PSU to test, or available to borrow for testing, contact a local shop and have them diagnose your system.

 

[DaleH]

I measured the clock on pin 6 on the BIOS chip. It is 0V. It looks like the clock generator is dead.

PS: after the first mainboard died, I purchased a used one (pretty expensive). It died 1 year later in the exactly same way.
So, I am somehow afraid to reuse the PSU. Maybe it killed the mobo?

How did you measure the clock? If this is the clock signal, one would have to use an oscilloscope for measurement.

 

[Flayed]

Some weeks ago, my beloved 10 years old PC went belly up 😥.

At least you got your money's worth out of it. Time for a new romance?

 

[Ancipital]

How did you measure the clock? If this is the clock signal, one would have to use an oscilloscope for measurement.

Not really. The clock is an (interrupted) DC signal. Can be measured with the cheapest voltmeter (but I have a good one). You need an oscilloscope only if you want to check signal frequency/quality.

ANYWAY

Good news! I fixed the mainboard!​

"Mechanical" problem!
On the BadCaps forum somebody mentioned that it wanted to recover the heat sinks from the mainboard. When he tried to removed them he heard a click. Then he tested the board and it worked. I tried the same. I bent the board and I heard a click. I connected only the two power cable and guess what! The buzzer beeped!
Now the PC is running, right from where it left.
Initially it didn't recognized the USB devices. It asked me for USB drivers, for the USB3 chip..... strange....

Now everything is fine.


I know, the board is not to be trusted anymore and might die any day.
It might work another 10 years, it might die in a few months.
Probably the bad IC needs to be identified and re-soldered.

I will prepare to build a new PC...


PS: This is the second mobo (identical) that dies on me, this way. Maybe the first board can be repaired the same way....
But I just installed all cables. I don't want to open the computer again, to try it.