Computer not starting

[Groog]

Hi, I'm hoping someone might be able to give me some advice for what my next debug steps are...
My (quite old) computer was working this morning (playing games etc). However, turning it on this afternoon and it does not start:

• Press power button
• Fans turns on
• Motherboard CPU_LED turns on (not sure if this is normal or not), motherboard manual does not give any detail on what this means. But I'm guessing it could be a CPU issue which in turn could be a motherboard/power supply issue?
• Graphics card RGB flashes yellow twice (not sure if this is normal or not) and then goes to its RGB breathing mode
• No output to display, so I can't get to the BIOS
• After a 5-10 seconds the computer turns off
• After another few seconds it turns on again with the same behaviour
• This loops a number of times and then it just turns off for good

I have tried removing the graphics card and connecting my monitor to the motherboard. Still not display output.
I have tried replacing the CMOS battery. No effect.

My gut tells me that I have a dead motherboard/CPU, but it could also be a faulty power supply.

From these symptoms can anyone recommend what is most likely faulty, or if there is anything else I can try?


Specs:
i7 6700k
Asus Pro Gaming Z170 motherboard
16 GB RAM
500 GB NVMe SSD
500 GB SATA SSD
Zotac RTX 4070 (the only upgrade I've done)
750 W EVA power supply

 

[wookiee87]

if you take the 4070 out and try to power on what happens?, how old is the power supply?

 

[Groog]

Same thing happens with the 4070 removed. Power supply is probably 6-7 years old.

 

[wookiee87]

I would say the psu is the problem, if it worked before putting in the new card then the power the 4070 has pulled has probally damaged something.
do you have a spare psu you could try without the 4070 just to make sure the pc will power up before buying a replacment unit?

 

[IntMD]

The CPU led staying on would indicate a CPU problem... unfortunately, it still could easily be either of the other 2 causing that problem. Would be pretty cheap to check the CPU, you can get a Pentium G4400T for £2 from the store named like sex which should be supported by your motherboard and assuming you dont have access to anything else that would work in your system.

 

[Tetras]

• After a 5-10 seconds the computer turns off
• After another few seconds it turns on again with the same behaviour
• This loops a number of times and then it just turns off for good

It could be a memory problem.

What is your CPU cooler?

 

[Groog]

Would I not at least get a POST if it was a memory issue?
Cooler is a beQuiet Dark Rock Pro 3. So annoyingly the RAM is underneath the cooler.

I did just try removing the cooler/CPU and putting it back together (simple to do, but long shot), no change.

Good idea on trying a cheap CPU to debug, I might give that a go.

I've not got a spare power supply, but there is a computer shop down the road I might be able to work something out with (closed for the weekend now).


Thanks for the ideas!

 

[Groog]

A wee update.

I borrowed a PSU from a friend. Tried it in my computer and got the same issue.
I bought the £2 CPU that @IntMD suggested and it the same issue.
I tried popping out each of my RAM sticks one at a time to see if they were causing the issue (as per @Tetras suggestion) and got the same issue.
So I think that leaves me with having a dead motherboard and a 6700K that probably works, but I have no easy/cheap way to tell.

I had been stalling on upgrading for a while, so my solution was to bite the bullet and I got a 7800X3D, motherboard, RAM, and new cooler and now have a really quite up to date machine!
I used my existing boot NVMe SSD and had a really annoying issue with Asus motherboard drivers clashing between my old motherboard and new motherboard, but managed to resolve that in a couple of hours.

Now that I have backed up all my files that I had been too lazy to actually back up properly... next step is probably to do a clean install and move to Windows 11 at the same time.

So thanks all for the help. And if anyone wants a 6700K plus cooler just let me know

 

[wookiee87]

definitely look at a re-install, moving from a intel build to a amd is a must, the amount of driver conflicts if you dont will be massive and will lead to multiple issues.
though if you had moved to a upto date intel build 12th gen or highter i would still sugest a re-install as drivers from 6th gen would still cause all kinds of weird things to happen.

7800x3d with a 4070 is a very good build and you'll see a huge diffrence in games once everything software wise is sorted out.

 

[Gray2233]

Tbh, I find W10-11 to be pretty forgiving when it comes to hardware changes compared to older o/s's. That said, it can be problematic, I'd recommend cutting off a smaller partition for your Windows install so that it's easy to format/reinstall when necessary.

That way you'll not lose much other than Windows and a handful of APPS when/if it becomes necessary.

 

[Groog]

7800x3d with a 4070 is a very good build and you'll see a huge diffrence in games once everything software wise is sorted out.

I was able to play most games at 4K, 60ish FPS on (very) low settings.

Now can easily get 90+ on 4K ultra. The biggest improvement is the 1/0.1% FPS lows. Everything is consistently smoother. Not a surprise, but very welcome!

The only problem I've had so far without a Windows reinstall turned out to be a BF2042 new kernal anti-cheat issue with Asus motherboards. Have worked around that until they patch it. Nothing to do with driver compatibility.
Regardless, I don't keep a lot of applications/games installed on my boot drive right now, nor do I customise the OS much. So a reinstall should be fairly painless.

 

[boabs]

deffo wouldna use 6/7 old psu on 4070

 

[Groog]

Aside from general aging, is there a specific concern with an older PSU?
I remember reading that some PSUs can't handle the peak power draws newer RTX cards. But if that was an issue I'd have seen it already.

 

[Tetras]

Aside from general aging, is there a specific concern with an older PSU?
I remember reading that some PSUs can't handle the peak power draws newer RTX cards. But if that was an issue I'd have seen it already.

Yeah, older Seasonics would trip with some of the newer cards due to the power spikes, it was most common with the Focus Plus models that were replaced by the Focus GX.

Group regulated PSUs are also not designed for these cards, but they're only available in budget PSUs now.