Question PC wont turn on, I've already replaced the motherboard and PSU ?

Jun 5, 2025
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First thing I thought of was the power supply since its my oldest part and every time I turn it on I hear sparks, so I went ahead and swapped it with a new one. Then I tested it with just the motherboard and some fans plugged in no GPU or cpu just barebones. The fans spun for literally a second, then stopped. No power after that.

So I figured maybe the motherboard was a problem too. Swapped it out for another one that im sure is working, installed everything back in: CPU, RAM, GPU, etc. Hit the power, and same issue. Fan spins for a second, then stops. Nothing else happens. it’s always the same case fan that spins: the one connected to the CPU_FAN2 header. I’ve already tried clearing CMOS still no luck tho. Pls help.

PC Specs
Motherboard: ASRock B550 Steel Legend
CPU: Ryzen 5500
GPU: RX 6600
PSU: MSI 750w
 
Show a photo of your system with side panel removed.
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You replaced PSU. Are both PSUS (old and new) modular?
Modular PSU cables are not compatible between different PSU models.
You have to replace all modular cables with new ones.
Using wrong modular cables can kill hardware connected.

Then I tested it with just the motherboard and some fans plugged in no GPU or cpu just barebones.
So I figured maybe the motherboard was a problem too.
BTW - this test was pointless. You can't start a pc without cpu/ram.
And you can't determine motherboard fault from that.
What did you expect from this test?
 
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you have to install the GPU, your CPU doesn´t privde a video signal to the motherboard. Connect the vide cable to the GPU and monitor, not the motherboard

the motherboard might have an old BIOS installed and the Ryzen 5500 might not be running on it.
it requires to update the BIOS with Matisse, Renoir or Vermeer CPU, then you can install the Ryzen 5500
 
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Show a photo of your system with side panel removed.
(upload to imgur.com and post link)

You replaced PSU. Are both PSUS (old and new) modular?
Modular PSU cables are not compatible between different PSU models.
You have to replace all modular cables with new ones.
Using wrong modular cables can kill hardware connected.


BTW - this test was pointless. You can't start a pc without cpu/ram.
And you can't determine motherboard fault from that.
What did you expect from this test?

Show a photo of your system with side panel removed.
(upload to imgur.com and post link)

You replaced PSU. Are both PSUS (old and new) modular?
Modular PSU cables are not compatible between different PSU models.
You have to replace all modular cables with new ones.
Using wrong modular cables can kill hardware connected.


BTW - this test was pointless. You can't start a pc without cpu/ram.
And you can't determine motherboard fault from that.
What did you expect from this test?
The replaced PSU is new and fully modular. I thought I would at least get light from my mobo from the test. That would tell me that its working? 😅😅😅

View: https://imgur.com/a/GKqTuS3
 
monitor plugged into the gpu and not motherboard ?
psu fully connected? some split the main connector in 10 plus 14pins on the psu side

connect the ram to slots a2 and b2 (2nd and 4th slot counted from CPU)

update the bios of your working motherboard to support the new CPU
 
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