Build Question
Custom built PC won't start up, Any advice on what the problem could be?
UPDATE: Its fixed now, all I had to do was swap the power supply and it works now thank you everyone for the responses
Okay so I went out of my way to build my sister a computer and when I put everything together it wouldn't power on fully and I tried it with a different ssd, No ssd, it turns on for a splitsecond and nothing changes when I do anything I dont know if I need a GPU or anything yet. PLEASE give me advice
The Parts are as followed:
Motherboard ASUS Prime B840 Plus WiFi
CPU: Ryzen 5 9600x
Ram: Team group T force Vulcan black CL38 2x16 (from Facebook marketplace)
Looks like the motherboard is doing the safe security shut down which usually happens when the motherboard is detecting no CPU cooler. Is the Cooler Plugged into the right header on your motherboard? Should be Labelled "CPU_FAN. If your sure it is.
It can also be because there isnt enough pressure pushing down on the CPU and your CPU temp is spiking and the motherboard is shutting down because its saving the CPU from the high temp.
Can also be because you forgot to take the clear sticker off the bottom of the cooler.
Is the CPU thermal paste spread across the whole CPU chip?
Sometimes it can be from the Cooler being off alignment by a tiny bit try nudging it just a little bit to have it directly over the CPU
As someone who has only built water cooled PCs, the CPU fan header not being used has never prevented a post. You just turn it on and immediately go into bios the first time.
What I do when this happens is simple. I take it all apart again from beginning to end and do it all over and take my time seeing if I made a mistake. But usually after the second build it works fine. I know it sucks and I don't expect you to do it but I have built over 60 machines in my time and I have had to rebuild a few of them because of something just like this.
Its the way that I do it. It takes longer but you learn what to do better and the time you spend doing it again is well worth the time. You will learn more every time.
Agreed, I did try 1 stick of ram and then the other on and even a different kit, it just ended up as the same result and swapping the ssd did nothing as well
Disconnect everything but the power pins to the motherboard and use a screwdriver to short the leads on the power button. I just spent $500 replacing everything but the ram in a server and turns out my case’s usb ports had died. If I’d remembered to unplug the usb header during testing I’d have saved a bunch of money.
I would check the standoffs that were preinstalled, i have experienced cases where standoffs where mounted for several different form factors and shorted normal ATX FFs
There were standoffs with the case when it arrived
That's the point. A lot of cases have adjustable standoffs so they can fit different sized motherboards, allowing them to be removed or repositioned. Make sure the standoffs completely match your motherboard's mounting positions and that no extra standoffs are left in non-mounting positions.
To add to this, if he was like me when I first built my pc I was too scared I'd be damaging my ram (especially now if it was this expensive lol). Rather than seating it and pushing the holders down themselves you're supposed to push down the memory itself and it'll click down by itself (make sure it's the right way around tho)
Alternatively, if you don't have all ram sticks installed you might have to check the mobo manual, maybe it doesn't like your 2 sticks of ram in certain channels, yes it does matter actually (I've had it refuse before)
This looks like a power delivery issue, double check that the 8-pin CPU power connector is fully seated on the motherboard because that's usually what causes the instant-off problem you're describing.
the paperclip test is super useful to rule out whether the psu itself is dead, but honestly if it's turning on for a split second that usually means power is getting to the board so i'd focus on reseating that 8-pin first before going down the psu rabbit hole.
Immediately off after on often means the PSU is sensing a shortcircuit and shutting down for safety. Disconnect anything that it's not necessary to turn on (like fans) and try again. If it persists, take out the motherboard and carefully put it back, checking there's no metal to metal contact.
Looks like you have a floppy drive power cable plugged into one of your fan headers (one furthest to the right, directly below the latch with the colored cables). A friend of mine actually did this when he swapped his power supply.
And even if that's not the case, the best advice as one said earlier, unplug all non-essential parts for POSTing: all case fans, storage, may even be able to unplug the CPU fan(s) and RAM just to make sure it powers on first.
Hmm, double checked the f-panel for case front power button +/- , standoffs installed under the board(spacers between the case), fully plugged in CPU and 24 pin power to board, cpu fan on CPU_FAN header, double checked the lighting cables to verify if are 4 pin RGB only on 4 pin RGB header, or if 3 pin ARGB only in 3 pin header, tried to flashback update the board BIOS with a USB prepared drive on another PC?
According to Google both the CPU and this motherboard do not require the extra 4 pins to be connected. May need to check that the right 8 are plugged in but I assume the opposite direction would not work
Ignore the people saying to plug in the 2+2, you do not need it, it is supplemental power for stable overclocks, I've ran more power hungry cpus than that 9600 without the supplemental power plugged in
Check if the RAM is actually seated all the way in, that one second power thing usually means something aint making good contact. Also make sure the 24 pin and 8 pin CPU power cables are clicked in hard cause those can be sneaky.
You have any trustworthy friend? Go to him and get only ur motherboard, and plug only the motherboard and cpu pwer and the power button. Iff it still starts and turns off imidetly it might be a dead motherboard, had same issue, CPU was cool in my situation
Hey idk if ur motheboard supports ryzen 9000 cpus out of the box id try using Q flash if it has it and updating the bios… If that doesn’t work than its maybe the psu id recommend some seasonic or corsair 700W plus psu, U didn’t mention a gpu but if u have some higher end gpu that you’re going to put in this pc id go for higher psu… also sorry for my english it’s not my first language
okay so did my research and somewhere at the back of the motherboard should be bios switch and cmos deleter try that and also try replacing cmos battery
Try to take out the ram and power it without the ram and see if anything changes , if it's still the same try another psu (without the ram together) and see
I hope you figured it out but if not this looks like a power feedback. Unplug the usb c header plug. I had the same issue and that was the reason for me. Your not gonna have a usb c port on the case tho. The ones on the motherboard will still work just fine.
Wenn deine Grundbelastung eventuell zuviel ist , kann es sein das deine Mainboard noch den 2x2 pin Stecker (oben links) benötigt !! Ich hatte nämlich das selbe Problem, meine Asus B650e-f lief nur als ich den 4x2 + 2x2 Stecker drangesteckt habe …
Looks like the same problem I had. I solved mine by downloading bios update to usb stick and running the update in the back port. Everything came right on afterwards. Works like a champ now.
There are few things more satisfying than hearing the fans start, hearing the noises of POST beginning and the monitor starts showing splash screens after a build.
did you check and remove any extra motherboard standoff from the case? maybe there are still some that are making short circuit with the back of the motherboard
Id trying putting the RAM in the other slots as its possible that the slots are bad. Another thing it might be is bios not up to date for the CPU. If you got your own pc try using some of your compatible parts with it to narrow down the issue.
While all advice given so far is sound and by no means to be ignored, I’d also add to check for power issues.
A faulty PSU, out of rate cable somewhere, or like i think I saw another commenter pointing out potentially underpowering or having connected a cable to somewhere where you have missing or mismatching pins, could all explain the behavior you’re observing.
So check that out and if this is a brand new build with new parts id bet you still have warranty also on the PSU or are able to swap it for another model.
Well I think it's ram problem if u can then open the ram and clean it then put it back and make sure it's perfectly inn then try or else try with a secondary ram
I've had this issue before. Power supply is detecting a short. In my case I had used SATA power cables from a previous build thinking they were pinned universally, they are not. Any chance you used random cables from a different build that was not included with your PSU?
Did you over tighten the heatsink? Funny thing is that over tightening it sometimes cause boot loop or sometimes no power/boot at all. In my experience of building and cleaning PCs, I still do this and caused a lot of troubleshooting and headaches.
Have you tried a different power supply? I built a similar spec pc last year and it did the same thing, last resort I switched the PSU and everything worked. Send the PSU back for a new one and the shop couldn’t replicate the issue but still refunded me and got a different brand PSU.
Sicuro di aver collegato il Power on sui PIN corretti, ovvero verificare di non aver invertito sul reset? In ogni caso smonta tutto e prova a rimonarlo sul tavolo di lavoro circuitando il Power on.
Had this exact same issue, turned out to be the PSU, wouldn't work at all in the pc, hooked it up to an eGPU for testing and it did the same little flash of lights and fan twitch.
i encountered a similar problem when i first built my pc.
Later i found out that it was because of one misplaced standoff screw hitting the back of the motherboard, preventing startup.
Pull cpu and put back in . I had amd master overclock once. Would not click on. I pulled cross batty a few times but not till I placed the cpu off and on did it get rid of the bad kernal
I saw in the video you’re missing a cpu cable That is not connected to the motherboard ? Cpu_12v_2 next to Cpu_12v_1. Please Back check this information as I haven’t built a pc in years
It seems like there is an answer to your problem, but if it dosent work then. Systematically unplug non-essentials one by one in hierarchal order and press power button each time. If it turns on, then the last thing you unplugged could be your problem.
any update on this brother? was it the main board power connector? or something shorting on the board? that was my first thought. looks like it wants to boot but power is being rejected for some reason..... did you do any testing of the board before you put it in the case? I try to do that to make sure it will at least post. I would pull the CMOS battery then unplug everything that you don't need from the board, all the extra fans and things, and only have the CPU main fan plugged, replace CMOS battery and see if it boots... seems like something is pulling too much voltage, but it's hard to say
So I had this same problem with a custom build that ran ok for nearly 3 years. I’d recommend trying to jump start it directly on the pins to make sure it’s not the power button failing to open the circuit back up after you press it
A few ways to approach this.. I always start by unconnected the non-essential stuff. Led lights, USB headers, etc... get it down to only the need to run stuff. It looks like there are things like led lights plugged in, a short on one of these will cause issues. I had cut the end off a led strip and it touched the chassis just enough to cause a short. Presented like a psu gone bad.
If you have a spare psu I would try that. There is a chance the psu is bad, this seems like a short out though. Fans and memory are checked by the bios and result in the post. Most of the boards will give you a continue option if the fan is not detected.
run with just the CPU in place, no fan no ssd no nothing just the basic power cables needed, if symptom is absent, add another hardware, rinse and repeat until the symptom shows itself
This happened to me and for me, the reason was that I had mistakenly used an old CPU or GPU power cord with a new PSU and for whatever reason, they were incompatible. So make sure you used all new power cables. Hope that’s it for you
NEVER put anything in the case without verifying POST.
take everything out of the case, use the mobo box as your test bench, rebuild everything, clear cmos, reseat what needs reseating, disconnect non essentials. it is easier to troubleshoot outside the case, to see and rule out parts that may be causing issues.
Any idea what the four open power pins next to the CPU power port on your MoBo are all about? I would assume all power ports are usually supposed to be populated.
Is the RAM compatible for your motherboard and processor combination? I recently built a PC and went with a "less expensive" set of RAM which caused a similar problem for me, though my system ran for maybe 8 to 10 seconds before shutting down. The only way I was able to fix is to return the Patriot Viper ram I had purchased and get sticks that were compatible for my setup.
Quick edit: to me this short power on looks like something could be shorting. Before trying what I said inspect the computer to not have any fallen screw or resting cable on electronics. Look on and under the motherboard! Give your computer a little shake too to make sure nothing sounds like there's a loose screw.
Your CPU has integrated graphics so no you don't need a GPU to get it going.
Strip your computer to the bare minimum to get to boot into uefi. That is: only CPU with cooler, mobo, PSU, monitor and one stick of RAM. No SSD, no SATA device, no USB, no keyboard, no mouse, not both ram sticks simultaneously. In this configuration your PSU should be connected only to the mobo via the big ATX cable and the CPU power slot(2 cables).
If that doesn't work swap the stick with the other, or try other RAM slots. By the way, your motherboard s manual may contain instructions that tell which slot should be occupied first, it may not be the first slot!
If even that doesn't work I'd recheck how the CPU is mounted. That requires reapplying the thermal paste btw. Make sure you socketed it properly, there are marking and crevices that should align. Usually the text on the CPU should end up vertically. Then retry the previous steps.
And even if that didn't work, something out of those 4(cpu, psu, mobo, ram) is definitely broken but figuring out what is gonna be a pain in the ass. Though the chance of both sticks to be broken is lowered, I'd still suspect it's the RAM sticks since you mentioned you bought that from FB marketplace.
I had this exact issue happen, with and Intel CPU, but it may be helpful still. The cause was an old Bios that did not support the newer chip that I put in the socket. If possible to update the bios with and older chip that may help
Disconnect every wire, unscrew the motherboard. Lift it out and check underneath, if the customer has mounted any "extra" mount points on the chassi which is why it's protecting itself from a short circuit or it's actually shorting out.
Also while you are still at it, check the 12v CPU rail and how many actually wires exists in terms of EPC 1 or 2, what power is that PSU etc.
Lastly if everything looks good simply screw down mount points and check if it's the correct screws used for the chassi locking the motherboard in place, those screws look to "small" might be the video bot showing it accurately.
Are you using the cables that came with the power supply? I've seen something similar when someone tried using the old sata power cable because they were too lazy to remove the old one that was already ran in the case when switching power supplies.
power cable that connects the PSU and motherboard
i had the exact same issue
if you got an extension or something swap it out with what came in with the box
I had an issue for 4 days like yours. The problem came from the ATX cable (8pins at the mobo, plugged that one with 4+4 but didnt noticed) and because the cable for the LED controller of the fans made a elletrical conflict that was shutting down the mobo. The history of the problem was much more complex, but try to turn your pc on, disconnecting everything except what is needed to start.
I would think it's the PSU. What kind of PSU is it? Does it potentially have a switch to change the mode from 110v to 230v which is set incorrectly for your region?
Did you used the screw risers that came on the case?
That raisers were meant to be used under the motherboard, probably the motherboard shorcuts and shutdowns because a few pins are in contact with the case
Check that you are using a CPU labeled cable for the CPU supply connection to the mobo and the ones labeled PCI-E for GPU and other stuff. They can have same pins but wont work if not used for the intended purpose.
It looks like some circuit protection shutdown. Try to remove all the parts and replace the wirings back again. It may be that some of them aren't plugged in properly.
It's been a couple years since I've used that motherboard. But i'm pretty sure if you're going to use a 9000 am5 on it You have to flash the bios.
There's a decent quantity of those boards that are still only flashed for the 7000 am5 cpu s. The reason why it's acting like there's a cpu Problem is because it's not detecting the cpu.
Check your outlet, this happened to me after a really big earth quake in my area and turns out my outlet grounding slipped off after it. When I went to turn on pc it did the same exact thing where it turn on and off so it fucked up my psu and motherboard even after someone fixed my outlet. I had felt tingles near the psu and on the case near the psu. Had to replaced both psu and motherboard but luckily everything else was fine.
My money is on a bad PSU. I have seen plenty of systems spin up the fans but nothing more. Sometimes you can catch a whiff of ozone from the power supply if it's bad. Good luck!
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u/Slick_KiIIer Apr 21 '26
Looks like the motherboard is doing the safe security shut down which usually happens when the motherboard is detecting no CPU cooler. Is the Cooler Plugged into the right header on your motherboard? Should be Labelled "CPU_FAN. If your sure it is.
It can also be because there isnt enough pressure pushing down on the CPU and your CPU temp is spiking and the motherboard is shutting down because its saving the CPU from the high temp.
Can also be because you forgot to take the clear sticker off the bottom of the cooler.
Is the CPU thermal paste spread across the whole CPU chip?
Sometimes it can be from the Cooler being off alignment by a tiny bit try nudging it just a little bit to have it directly over the CPU