The PSU passed the paperclip and multimeter tests, yet the PC fails to start.
The PSU passed the paperclip and multimeter tests, yet the PC fails to start.
I just put my PC back together yesterday after not using any parts for 1.5 years. Everything started working properly except the GPU, which wasn’t sending any signal (lights came on but that’s all – important for what happened later). I unplugged the GPU and connected the monitor directly to my MOBO, and everything seems to be running smoothly now. I went ahead and turned off the PC, finished organizing the cables, and when I tried to restart it again, my PC didn’t boot up. There were no lights on the MOBO, and the PSU fan wasn’t running. I checked all the connections and they looked correct. I removed the PSU and did a paperclip test plus used a multimeter to verify the voltages – everything was within the expected range. Then I reconnected the 24-pin and CPU cables back to the MOBO and turned it on. The MOBO lit up briefly, then the lights went off. Now it’s exactly how it was the previous night, and nothing is booting up. I’m rechecking the PSU with a paperclip and multimeter, and the readings look normal. Here’s my build list:
i7-7700k
Hero Maximus IX
RTX2080
Kraken x62
2x Corsair vengeance 16GB
Corsair CX600M
It’s worth noting these components have been in use for a while – the CPU and RAM (about 5 years), GPU (3 years), and PSU (9 years). My guess is the PSU might be getting old enough to no longer support the system properly. If I decide to replace it, I’d like some advice before spending around a hundred dollars on something that could have been the issue. What do you think?
Since you don't have an extra PSU, I recommend using the multimeter in AC mode to test for average ripple at 12v, 5v, and 3.3v. Make sure to verify with both directions—check one way, then reverse the leads and retest. Keep in mind the ATX specifications state a maximum ripple of 120mV on 12v, and 50mV for 3.3v and 5v.
Just to confirm your approach, you are checking the final "settled" value or observing the peak when touching the probes to the pins, or calculating an average of readings?
A multimeter provides only an average reading, so it can only indicate whether the ripple is severe enough to require replacing your 9-year-old PSU. To see peak values, you'd need an oscilloscope.
I’d just go ahead and swap it out anyway. It was always a very inexpensive, group-approved PSU that didn’t suit an RTX 2080 anymore, now it’s another budget model that’s been around for years and is probably over ten years old. Corsair CX PSUs only became affordable options with the introduction of gray labels in 2015, and their wattages are all ending in 50 instead of 00. This unit should have been replaced long ago, especially when trying to bring this PC back to life.
You don’t need to spend a few hundred dollars to get a solid PSU. A good Tier A unit would cost around $100, and for higher wattage models that handle more power, options like the Corsair RMx 850W are only about $130 to $140.
Avoid the CX series, move to a higher tier. The newer models perform better, though a power supply remains a significant long-term expense. Consider allocating a bit more to the budget if feasible.