Random Shutdowns/Startup Failure with Corsair SFX 450

[h0m3w0rk]

Hello everyone,




I'm encountering a frustrating issue with my Corsair SFX 450 power supply. After an undefined period of operation, my PC will either suddenly restart or, in some cases, it won't start at all until I disconnect the power cable and reconnect it. This erratic behavior occurs intermittently, making it difficult to pinpoint the exact conditions under which it happens.




For context, I have tested the PSU using an electronic load at 150W, and under those controlled conditions, it functions flawlessly. This leads me to wonder if the issue might be related to transient loads or specific operating conditions in my system that aren't replicated by the bench test.




Here are a few details about my setup and the problem:

• PSU Model: Corsair SFX 450

• Symptom: After an unspecified runtime, the PC either restarts unexpectedly or fails to start until the power cable is unplugged and reconnected.

• Bench Test: When subjected to a constant 150W load using an electronic load, the PSU operates perfectly with no issues.

• Observations: The problem seems to be sporadic. I have not yet identified a clear pattern regarding system load or external factors that trigger the issue.




I'm curious whether anyone else has experienced similar symptoms with the Corsair SFX 450 or other SFX power supplies. Could this be a fault related to voltage ripple, transient load spikes, or perhaps an issue with the PSU's internal protection circuitry? Any suggestions on further troubleshooting steps or tests to help narrow down the cause would be greatly appreciated.




Thanks in advance for your insights and assistance!

[h0m3w0rk]

IC`s on the PSU:

Supervisor IC: IN1S429I-SCG
SLS (SRC/LLC+SR) Controller: CM6901X
Gate Driver: SI8230BD
Phantom Power Remover?: CM03AX
PFC: CM6502UHHX
ICE5QR1680AG

[прямо]

CM03AX is a MOSFET, from the same manufacturer for the PFC+PWM chip.

Your 150W bench test load is probably too low for the PSU, hence the problem doesn't occur.

Increase the load.

[momaka]

For context, I have tested the PSU using an electronic load at 150W, and under those controlled conditions, it functions flawlessly. This leads me to wonder if the issue might be related to transient loads or specific operating conditions in my system that aren't replicated by the bench test.

Well, what hardware are you running on this PSU (PC components?)
A lot of modern GPUs since around the nVidia RTX series and AMD RX6k/7k series can sometimes power-spike quite a bit above their nominal rated TDP.
If you have an older power-heavy system, like a Core 2 Quad with a more beefy old GPU (GTX260-280, GTX460-480, GTX560-580, and etc.), try that on this PSU and see how it behaves. Chances are, it probably won't have any issues, as these older systems do not have silly power spikes like modern hardware does.

The only other possible explanation I can think of for this phenomenon is if you somehow have random power dips in your AC line. But I think that's less likely of a possibility for the issue, since you probably would see it crop up with the 150W electronic load too.

[stj]

make sure all the caps are good.
i had a psu that would shut down when hotswapping a harddrive on a server - it was causing a glitch because the caps werent up to the job.