Question PC died --> Installed new parts --> still dead ?

[Sushi VII]

My PC suddenly decided to not start up the night after I shut it off. Prior to that night there was a storm that took out the power, and when the power came back I was still able to power up and run my PC for the rest of that day.

The next day I tried turning on my PC and nothing happens. No sounds or mobo lights, just completely dead.

I've tried power cycles, trying different outlets, then I figured either the PSU or MOBO was dead, or both. I ordered a new PSU, MOBO, and thermal paste to reconnect everything with new cables, made sure the CPU was seated correctly and finished putting it together. I did test the new PSU and it works, but after I switched it on and tried pressing the power button on my PC, the same problem persisted with no lights or anything turning on.

I rechecked all the wiring, reseated the battery on the MOBO and it all seems to me that there should be no problems and I'm just at a loss now.

Specs off the top of my head:

MOBO: Gigabyte X570S Aorus Elite AX
CPU: Ryzen 9 3900
PSU: EVGA 750BQ Bronze
MEMORY: Corsair Vengeance Pro RGB 8GB (X4)
GPU: Gigabyte RTX 3060
STORAGE: M.2 NVMe Samsung 980 SSD 1TB
STORAGE: SSD 1TB (x2) connected by cable to MOBO
FAN: 3 Front Fans 120mm
COOLING: Water Cooling with Rear Fan
OS: Windows 10

 

[Misgar]

Over the years, I've had two lightning strikes near my house. On both occasions, there was a very loud bang when lightning struck tall trees close by.

During the strikes, conducted surges into my house along AC mains wiring, coaxial cables and telephone lines, destroyed my broadband modem, hardware firewall, Ethernet switches, telphone answering machine and other small items.

by the time the lightning strikes had finished destroying three series-connected devices, one after the other, the energy levels had dissipated sufficiently and my computers survived. I was lucky. Other people in the neighbourhood had wiring blasted out of interior walls and glass TV screens cracked.

The most sensitive parts in a computer to overvoltage/current surges during a storm are the mobo, CPU, RAM and GPU. Many circuits operate at very low voltages, down below 1 Volt. The highest input is the nominal +12V EPS rail. Surges of hundreds or thousands of Volts result from lightning strikes.

To a certain extent, the ATX PSU is more robust, because it's designed to work on the vagaries of an AC mains supply, up to a nominal 240V (plus 6% and transients). However, the PSU is often the first item in the chain during a conducted lightning strike and can die suddenly too.

You've already changed your mobo and PSU, but it's possible the CPU and GPU have died too. I'm not discounting faulty RAM either, but if your Ryzen 3900 is still working, I'd expect some signs of life in the new mobo.

Obtain/buy a cheap Ryzen CPU (anything supported by your BIOS will do). Fit this CPU into the mobo and attach the cooler. The idea is to try a different CPU in your new mobo.

Test your RTX 3060 in another computer to see if it's OK. If you cannot do this, obtain another working GPU. Anything will do, e.g. an old GT 630, GT 710, GTX 1030, etc.

With a known working GPU and replacement CPU in the new mobo, remove the RAM and power on the system. If there are signs of life with the new CPU, your 3900 has died.

Fit the RAM and see if the system POSTs. If it looks good, run MemTest86+ from USB to check the RAM has survived intact.

You should now know which components have died.

I've installed industrial spec lightning surge arrestors in all my coaxial antenna leads and RJ45 surge arrestors in critical Ethernet cables. I now have fibre-to-the-premises broadband internet, so that's one less line of weakness, compared to ADSL or cable broadband.

My main system is powered from a 1500VA APC UPS to provide a modicum of protection against mains surges. The UPS will probably die in a big lightning strike, but better it fails than a number of expensive PCs. I still expect to lose equipment in the next big lightning strike near my house.

Do not expect a single cheap mains surge protector strip to provide 100% protection. It can cost thousands of dollars to install adequate lightning protection.

Of course, your system failure might have nothing to do with the storm. It could be nothing more than a coincidence.

 

[Sushi VII]

Well I've tried replacing the CPU and RAM with new ones and it still didn't turn on, then figured it must be something to do with the circuit board that the power button is on. It was just that. I had to plug in a USB into one of the slots and press the restart button for it to somewhat jump it and everything turned on.

So looks like it's the front panel circuit board that's bad.

 

[Misgar]

If the switch or the cable have died, you could remove the front panel and replace the whole cable assembly.

This front panel kit includes:

Power switch
Reset switch
HDD LED
Power LED

https://www.ebay.com/itm/2713985332...soQ/UslvbPN7UCRaklAM+avFo=|tkp:Bk9SR5rzuPi5Yg



Alternatively, you could just buy the Power switch cable assembly on its own. Make sure the switch size/shape looks compatible with your front panel before buying.

https://www.ebay.com/itm/2817164917...39LSTL5nGwZnOlo59sJdRhhRA=|tkp:Bk9SR5rzuPi5Yg

Or, if you have a Reset switch on the front panel, just connect it to the Power ON pins on the motherboard. Many computer cases are not equipped with a Reset button, so I've got used to it not being available.