The PC stops immediately when using a new PSU, yet it functions properly with an older PSU?
The PC stops immediately when using a new PSU, yet it functions properly with an older PSU?
Hi, I had a query about purchasing a new GPU. I currently own a Nvidia Geforce GT 1030 with 2GB of GPU memory and it functions properly on my Dell U2717D monitor. Although I don’t play games much, I use Adobe Lightroom occasionally, and it works well with my 16MB RAW files. However, since my camera is quite old, I’m interested in upgrading to something newer... Forums. suggested I upgrade to a Montech Century II 850W. But this evening I was installing it and noticed all the fans and other components activating, then the PC would shut down and restart itself. I checked all connections and cables, but found nothing wrong. Later, after reconnecting the old PSU to the motherboard and storage drives, it started working correctly. My assumption is that the new PSU might be faulty or it’s detecting a problem that my old one is ignoring. Anyone have any advice?
Yes, I completely replaced the old PSU. Because it wasn't modular, all the cables were taken out. Now I'm using
- the new PSU inside the case with its cables still attached to it but not connected to the PC
- the old PSU is linked to the motherboard and disks only – that's about it. The graphics card doesn't require any extra power.
I would attempt with the least possible setup. No GPU, no storage, possibly nothing else—just to check if it remains operational (since without an integrated graphics card, images won’t display). If it stays on that way, I can add components one by one, turning off power each time. If it still doesn’t work, maybe try using a different PSU or test in another system. If the "paper clip" method is used to power it up, some PSUs might require a load to function correctly, so connecting an HDD could help.
Capture an image of the new PSU 24-pin ATX connector and check whether all the necessary cables are connected or if any of the 24 pins are absent. You may upload the photos to platforms like www.imgur.com to share here. It's possible that the PSU doesn't support a -12V rail with a 24-pin ATX cable, as newer Corsair models often lack this feature. The -12V rail is required for your motherboard to power the VGA port, but many modern motherboards no longer include this video port, and some PSU brands have discontinued it.
There seems to be a short circuit (likely).
Is the replacement PSU new or used?
If it’s used, it might have come with incorrect cables.
Please share a photo of your system with the new PSU connected and the side panel removed (upload to imgur.com and include the link).
Connect only the essential PSU cables:
motherboard 24pin,
motherboard 4+4pin.
(remove all other PSU cables and storage devices).
Attempt to start your PC. Check if it powers on.
After that, connect SATA cables and add storage devices.
Try starting again. See if it works.
Hi all, thanks for the responses.
I am a bit snowed under with work at the moment and so won't get a chance again to move it back to the new PSU until the weekend
But in terms of some of the questions
It is a brand new PSU
https://www.montechpc.com/century-ii-850w
In terms of what happens is that on power-on, the lights turn on and fans all start (include on the CPU), there is a beep and it powers off, then without any intervention is does the same thing again.
Note: since September imgur is not accessible from the UK
But Aecus you asking about the 24 pin connector there is one missing - looking front on with the clip at the top it is the 5th from the right is missing a cable and you can see the hole has no metal inside. If that is the issue can it be fixed ?
TIA Steve
One missing pin would be acceptable if it's a pin "N/C".
Here is the pinout for the ATX 24-pin connector, direct link if the image fails to load:
https://www.smpspowersupply.com/connecto...pinout.GIF
On the right side you'll find an older 20-pin ATX, and on the left a newer 24-pin ATX.
Check the pinout table and verify your power cable. Try to understand what is missing.
N/C (no connection) can be left blank. However, -12VDC should not be omitted.
You'd need an isolated +12V to -12V converter something like this. You don't need more than 30mA in most instances, but some mobos still need -12V.
https://www.amazon.com/Isolated-10-8V-13...B0F4DP76PV
You need to be handy with a soldering iron and bodge the converter into an ATX extender cable.
https://www.amazon.com/StarTech-8-Inch-P...B000FL60AI
I did see mention of Corsair offering a ready made module for people who still need -12V but I'm not sure if this still exists.
The "best" solution is to buy another PSU which still has a -12V rail. Unfortunately Corsair seem to have abandoned -12V because it's no longer mandatory to comply with ATX 3.0/3.1.
I was intending to upgrade an old PC to a Corsair RM1000x but I'm switching to one of the many other manufacturers who still include a -12V rail in their ATX PSUs. So far, I haven't found any other locally available PSUs apart from Corsair which don't still include -12V.
Corsair's decision to save a few dollars from each PSU by omitting -12V might make sense from a commercial point of view, but it means I'll abandon Corsair as my preferred brand when replacing PSUs in old computers.
It's not impossible to wire up an ammeter and break into the -12V wire in an ATX extender to check for a few mA on the -12V rail in an old build, but it's less hassle to buy a new PSU which retains this "obsolete" rail.
Hi everyone
Just finished trying again after some time.
The new PSU's cabling shows a 12v connection.
I took out the old graphics card and sound card individually—no difference in results.
Memory was also removed.
Every setup gives the same outcome: power is pressed, everything starts up (like fans and lights), one beep, then it shuts off again.
I’m thinking it might be the power supply itself. I’ll check if anyone knows a local PC repair shop that could test it.
Thanks!
Steve