Question PSU passes paperclip and multimeter test but PC doesn't start ?

[ryane01]

As titled, I just reassembled my pc together yesterday after not using the components for 1.5 years. Everything turned on alright except the gpu was not outputting any signal (lights turn on but that's it - important for context later). I unplugged the gpu and connected the monitor directly to my MOBO and everything seems to be going smoothly. I proceeded to turn off the PC and finish up cable management and when I tried to turn it on again my PC does not boot up. There are no lights on my MOBO and the PSU fan wasn't running. I checked all the cables and they seem to be connected properly. I've disconnected the PSU and did a paperclip test and used a multimeter to check the voltages and they seem to be in correct range. I plugged the 24-pin and cpu cables back to the MOBO and turned the switch on. The MOBO lit up for a sec and the lights went off. Now it is the same as it was last night and nothing boots. I'm checking the PSU again with the paperclip and multimeter and the values seem to be in the right range. Below is my build:

i7-7700k
Hero Maximus IX
RTX2080
Kraken x62
2x Corsair vengeance 16GB
Corsair CX600M

One thing to note is that these components have been around for a while MOBO CPU RAM (5years), GPU (3years), PSU (9years). My hunch is that the PSU is getting a little too old and unable to support the PC anymore (when the GPU worked it worked for like 5 seconds but stopped after that). I'm thinking of getting a new PSU but wanted second opinions before I drop a couple hundred dollars for something that may not have been the culprit.

Thoughts?

 

[BFG-9000]

As you don't appear to have a spare PSU, I'd suggest setting the multimeter to AC to check for average ripple on 12v, 5v and 3.3v. You have to check with the leads in both directions as only one way works (check it and then reverse the leads to check again), and note the ATX spec is a maximum ripple of 120mV on 12v, and 50mV for the 3.3v and 5v.

 

[ryane01]

As you don't appear to have a spare PSU, I'd suggest setting the multimeter to AC to check for average ripple on 12v, 5v and 3.3v. You have to check with the leads in both directions as only one way works (check it and then reverse the leads to check again), and note the ATX spec is a maximum ripple of 120mV on 12v, and 50mV for the 3.3v and 5v.

Just to be sure what I should be doing - I put the multimeter on AC reading and probe the value readouts. Am I looking at the final "settled" value or looking at the peak when I touch the probes on the pins or the average of some sorts?

 

[BFG-9000]

Well a multimeter really only gives an averaged value so can only tell you if ripple is bad enough that your 9yo PSU needs recapping. If you wanted peak values it'd really take an oscilloscope to show that.

 

[DSzymborski]

Honestly, I'd just go ahead and replace the PSU anyway. It was always a very cheap, group-regulated PSU that was inappropriate for an RTX 2080 and now it's a very cheap, group-regulated PSU that was inappropriate for an RTX 2080 that's been sitting for a years and is likely over a decade old. Corsair CX PSUs didn't become good budget options until the gray labels started coming out in 2015, and the wattages all end in 50 rather than 00. This PSU should have been replaced under any and all circumstances years ago, and certainly when trying to revive this PC.

You don't need to drop a couple hundred dollars to get a good PSU. You ought to be able get a Tier A PSU for around $100 and if you want a larger wattage for newer, high-end PSUs that use a lot of power, stuff like a Corsair RMx 850W are only in the $130-$140 range.

 

[ryane01]

Well a multimeter really only gives an averaged value so can only tell you if ripple is bad enough that your 9yo PSU needs recapping. If you wanted peak values it'd really take an oscilloscope to show that.

I'm getting readings starting at 190mV and then they drop down to >1mV. Just wanted to check if what I was doing makes sense. Does this mean that the average ripple is 100mV?

 

[ryane01]

Honestly, I'd just go ahead and replace the PSU anyway. It was always a very cheap, group-regulated PSU that was inappropriate for an RTX 2080 and now it's a very cheap, group-regulated PSU that was inappropriate for an RTX 2080 that's been sitting for a years and is likely over a decade old. Corsair CX PSUs didn't become good budget options until the gray labels started coming out in 2015, and the wattages all end in 50 rather than 00. This PSU should have been replaced under any and all circumstances years ago, and certainly when trying to revive this PC.

You don't need to drop a couple hundred dollars to get a good PSU. You ought to be able get a Tier A PSU for around $100 and if you want a larger wattage for newer, high-end PSUs that use a lot of power, stuff like a Corsair RMx 850W are only in the $130-$140 range.

I agree that the PSU needs replacing but I just want to make sure it is the only thing that needs changing 'cos getting PC parts in my area is a hassle and would like to just get it all at once.

Am looking at the CX750M. Thanks for the suggestion though!

 

[John Chesterfield]

Try and avoid the CX series, go a tier up from that. The newer ones are better, but a power supply is a long term investment. Put a bit more into the budget if at all possible.