I decided to clean out my CPU fan as it was clogged, when I assembled everything again it won’t turn on 🙁
It’s an old desktop PC. There are no lights glowing on the motherboard at all, though there is none specifically labelled “power”. Just CPU, RAM, BOOT. None of these light up, not even a flash when it starts.
I have reseated the RAM, CPU, power cables. Removed the GPU to check.
The cord leading in to the PSU works but I don’t have a way to test the PSU itself or the out cables, but I have reseated them at each end.
This PC was working fine before. But with no lights on the motherboard I suspect either the mobo or PSU?
Mobo is asrock x570 PSU is silverstone 650w strider gold S series
Any help appreciated!
Did you use compressed air to clean out the fans?
It’s possible to fry circuitry if you artificially rotate the fans too fast, as this generates an electric field more powerful than the fans and their attached components are rated for.
Probably rare to cause damage with modern computers but an old PC might be more susceptible to this type of damage.
Not compressed air from an air compressor, just the canned stuff. I don’t think I spun any fans too fast. Plus the PC is only 5 years old.
I joked the dust was what was keeping the PC running when this happened to me. But your explanation makes more sense. Dang
Have you tried turning it off and on ag- oh.
In all seriousness, maybe a blown capacitor of any kind? You describe the PC working fine ‘before.’ When was ‘before?’
There is no obvious damage on the motherboard, capacitors look fine.
“Before” was immediately before I turned it off and opened it up to clean out the dust. It was being actively used as a server.
You haven’t followed the proper tech troubleshooting ritual:
- Yell at it
- Ask nicely
- Blood sacrifice
- Lament
- Instigate violence (hit it)
- Completely disassemble and rebuild it
- It inexplicably works fine
- ( ◡̀_◡́)
- Is the PSU switch on
Well I got up to step 6, not sure how to get to the next step…
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Have you tries unpluging it and plugging it in?
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Is the power switch on the PSU flipped on? Are the front panel wires seated in the right places on the motherboard?
Those are the two that get me when reassembling. I used to have an asrock 320m that had absolutely no grip on the front panel wires and it was easy to unseat one when blowing air into the case.
I’ve flipped the PSU switch both positions, doesn’t really work either way.
I’ve reseated the case power switch cable but it didn’t help. I also tried shorting with a screwdriver in case it was the switch, but nothing 🙁
You mentioned a buzzing in another reply. That sounds like a grounding issue to me. Any chance you blew something under the board that is causing a short? At this point it would be wise to do a full tear down.
I’m almost at my train stop, so one final question before disappearing for the day: when resocketing the CPU did you put it in correctly and was there damage when you removed it initially?
Yeah I will probably do an out of case, mobo, RAM, CPU, PSU only at some stage tonight to test.
Yes on the CPU damage, some bent pins on a corner, but I straightened them and it went back in fine. I had assumed the CPU light would be glowing (or not glowing) if that were the issue, but I’m no expert. Maybe it is the CPU. Expensive to buy one just to test though!
Edit: oh and the buzzing is from the PSU, when off, and not connected to the PC at all.
These lights and beep sequences aren’t 100% reliable. So I wouln’t take it for granted. But it’s a bit suspicious in my eyes that none of the LEDs light up. Maybe it’s the PSU, then? I mean it could be anything. And in my experiences it’s most likely a cable that got unseated accidentally by the vacuum… But you mentioned it’s a server… And I’ve had PSUs fail after being online 24/7 for years, and then one day you turn off the power and they won’t ever come back. And with the bent CPU pins I’m not sure. Most of the times straightening them works, but sometimes they break off after doing that.
These kinds of diagnostics are next to impossible without some spare parts, to swap one at a time and see which is at fault. If you don’t figure it out by chance, you’d need to borrow some.
I’ve done a paperclip test, PSU fan starts up, but doesn’t when plugged into the mobo.
I have now done an out of case test, with CPU, RAM, mobo, PSU, and no luck.
I guess that means mobo or CPU is the issue. I would think if it were RAM the symptoms would be different.
I took the CPU out yet again, all the pins look fine. They didn’t get munched being inserted the last time, so it seems they straightened OK. But at this point it has to be CPU or mobo, surely.
Agreed. And I’d say the mobo is more likely, as it has more different components like capacitors and whatnot. So just by volume.
As a final test you could rip out RAM, GPU etc disconnect all unnecessary cables and run just mobo + CPU + PSU. See if it beeps/lights up or changes anything. That’ll rule out a short in some other component being the issue.
I mean we’re not 100% sure, but looks like you’re in for a new mobo (+CPU).
I already removed all cables and extras when I did the out of case test, didn’t think to try without the RAM. I will give that a go tomorrow, I’ve had enough for tonight,
It looks like I can still get a mobo that supports the socket, so in theory I should be able to just swap the mobo. But then if it doesn’t work I’ll have to get a new CPU next and then I’ll wish I didn’t get the mobo because I’ll probably get a more recent CPU. Hard choices!
For the moment, I have requisitioned a laptop and booted from the server hard drive, and things are back up and running. So I don’t have to rush, I’ll try some more tomorrow, have a think about what I’d like. Maybe I’ll just get something new, and auction off the mobo, CPU, RAM online $1 reserve and someone else can work out what does or doesn’t work . 😆
It does seem like that.
(Be sure to thank the kit for its years of service)And if you triggered any failsafes they would have reset by now.
The mobo button battery can rarely make seem the mobo dead, but usually still does at least something.
(I’m not saying it’s likely, just that it’s the last thing I can think of)It wasn’t that many years, I checked and I got the whole setup in 2019. A little over 5 years. It hasn’t been running as a server for that long, perhaps only 6 months. Seems like a premature failure. I probably messed it up by doing something wrong when cleaning. Static maybe? There isn’t anything obvious on the board that l can see, no burn marks, no ozone smell. I guess I’ll look at ordering a new mobo and then new CPU if the mobo doesn’t work. Annoying though, because if I have to get a new CPU I probably want an upgrade, but if it’s just the mobo probably not.
Thanks for the help 🙂
Did you maybe unseat the tiny power switch/activity led front panel cables?
I’ve tried just directly shorting the power switch on the mobo to rule out issues with the case switch, but that didn’t help.
Well, reading this and the rest of this thread, I can’t think of anything else. Since you ruled out pretty much everything else, I would now put my money on one of the parts shorted during cleaning… anecdotally I’ve heard parts dying by shorting them with your fingers, but it never happened to me, so that would be pretty unlucky.
Last time I did a cleaning of a particularly dusty system, a dustbunny flew in the PCI-e port without us noticing (it was dark and circumstances were not ideal). With the GPU Re-inserted, that was enough for the system to behave similarly to yours, but you re-seated everything so… That would eliminate this as a possibility.
You could share a photo of the current situation, a top down of the mobo? Eliminate chances you are missing something by secondary means(as opposed to just text)?
One thing that was only mentioned briefly by someone else is the physical button turning on the computer.
Similar to the paperclip test figure out where the power button goes into the mainboardw and bridge that with a short cable. Is possible that by moving the case the old button lost a cable.
This is just one more thing to test though, it’s really trial and error as you know :)
One of the first things I tested 🙂. I’m almost ready to give up, buy a new mobo/CPU/RAM and then auction the old stuff off online for someone else to work out what does or doesn’t work 😆
How does everyone have spare parts to try, it seems almost every generation you have a new CPU socket and new RAM type so you can’t use the old stuff!
I’ll probably be asking for hardware recommendations soon haha
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It’s an old desktop PC
One (or more) of the electrolytic capacitors in your PSU has died.
Remove the power cord, wait for 2 hours, open the PSU and look carefully for the candidate(s) with the domed head. Healthy ones are perfectly flat on the head.
Order a new one and replace it.
I did a paperclip test, PSU seems fine.
What did you do?
What did you expect?
What did you observe?
I followed someone else’s instructions. Expected putting a paperclip in in and plugging it in/turning it on would cause the fan to start up. It did.
https://robots.net/tech/how-to-power-up-psu-without-motherboard/
Fan in PSU started up fine, apparently this is a sign that the PSU is not dead. Fan does not turn on when connected to the motherboard, which supports the theory that the PSU isn’t the issue.
I had this exact issue on an old gaming PC, PSU wouldn’t power the MB, but would be fine by itself. My GPU had a short, gods know how it happened. Juts keep disconnecting parts and try powering up again until you get the LED indicator. If everything is gone and it still won’t power on, it’s the MB. You could get a multimeter and measuring the power lines to see if there is a short (5V to ground, 12V to ground and I think there are 24V lines?). Maybe look for burst or burned capacitors and if you’re crafty and able to solder replace them. Otherwise replace the MB or defect parts.
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Did you flip a power switch on the PSU at some point, perhaps? (Done that one a few times myself…)
I’ve tried in both positions.
Might sound weird but I can hear a quiet buzzing in the off position (O) and silence in the on position (1). But I don’t have another to check what’s normal.
It’s generally the reverse thing that happen you can hear the buzzing when on and not when off… 😁
That’s why I mentioned it! It seems logical. Normally 0 is off and 1 on, right? I tried in both positions but it buzzes when in the 0 position.
This sounds illogical to me
For the record, I did a paperclip test and the PSU seems fine. 1 is definitely on, 0 off, and the buzzing is when it’s off 🤷. It’s not loud, you can only hear it when held up to your ear.
Is there any chance the buzzing is actually from what you have the PSU plugged into? I think ive had a surge protector that have a buzzing without anything drawing power that went away once something was consuming power.
Definitely the PSU, but it’s not drawing power so maybe the buzzing would go away if the PC was drawing power.
And when you unplug the power it goes?
Yeah, may just be that the PC isn’t drawing power, the buzzing might go if it was.
Mind trying another power socket just to eliminate potential environment problems?
Did it, and also did a paperclip test. PSU seems fine, it’s getting power.
If you got another psu then that would probably be the simplest way to verify if its the psu or not.
I don’t. No other desktop in the house, no spare parts 🙁
It’s dangerous and you can blew it if you don’t know what are you doing but by shorting two specific pins, it’s possible to turn on the PSU and see it it’s working or not
Did you use a vacuum on the fans and let them spin during the clean?
Not on the PSU fans, and was using canned air cleaning stuff.
Someone else posted a link about testing the PSU. I’ll consider it.
When you tear down next, look for missing board components or any that lean at an angle they’re not supposed to. Canned air has been known to shear poorly-attached caps or whathaveyou clean off the board. Or maybe one of the wires in the 12v cable is broken and it’s delivering power just to most pins… The paperclip test just tells you if the PSU is dead dead, are you able to test with a multimeter instead?
Buzzing while the power supply is off makes me wonder if there’s literal bugs in it, if it’s buzzing while it’s unplugged. I suppose the buzzing could also be remaining power discharging, if it happens just after it’s been unplugged.
Honestly the canned air I have doesn’t blow that hard, it struggled taking the dust off I doubt it could damage anything. I have had a look over the board and there’s no obvious damage.
I’m thinking today’s plan might be to buy a multimeter.
The buzzing is immediately after being switched off, so you could be right, could be power discharging.
I pulled a psu out of my rig over the weekend. I was just going to chuck it on Trademe for $1. Let me know if you need it, though shipping might take a few days.
I did a paperclip test and the PSU seems fine, but thanks for the offer. Got to be mobo or CPU I think.
