No energy supply in the PC when the PSU is not functioning?
No energy supply in the PC when the PSU is not functioning?
Hello,
I checked the PSU using a Power Supply Tester and everything looks normal. The power ratings are within expected ranges: +5V = 4.9, +12V1 = 12.1, +3.3V = 3.3, -12V = 12.4, +12V2 = 12.4, 5VSB = 4.9 and PG = 250ms.
When I turned on the PSU, the two buttons on the motherboard (Reset Switch and Power Switch) briefly lit up, but no power was supplied. After turning it off, those buttons stayed lit for about a second.
I removed and reset the RAM several times, took out all drives, disconnected the power cable multiple times (including the ATX connection, which was necessary for testing). My motherboard model is ASRock 990FX Extreme 4.
Any advice would be greatly appreciated!
Regards
Dorian
When sharing a troubleshooting thread, it's standard to provide complete system details. Please format the specs as follows:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
Include the PSU age along with its make and model. Also, note the current BIOS version for your motherboard.
I tested the PSU using a Power Supply Tester and the readings are within normal range.
Do you have a link to the PSU tester?
sorry, I am in a hospital now, I wanted to get it working once I get back home. I did not think that all this data is essential for a problem solving suggestion. But PSU is KRPW-AK650W/88+ and Powersupply tester is a Coolmax PS 228 PSU Tester. Motherboard I mentioned already. OS = WIN 10. How would I know the BIOS version when I have no power? SSD/HDD C drive is SSD Samsung 500GB the others are HGST and Samsung.
Mod Edit
: is my question so difficult?
I own one of these inexpensive and cheerful PSU testers, but it only displays voltages without any load on the power rails. It doesn’t accurately reflect an ATX PSU’s capacity to deliver large currents across all three main rails. For a more reliable evaluation, you should apply typical loads to +12V, +5V, and +3.3V rails. Experts in PSU testing (such as Tom's) often use costly programmable digital loads. At home, you could substitute several 60W car headlight bulbs for a proper load. This would give you a clearer idea of whether your PSU is likely sufficient.
If this is your unit, it doesn’t give me much confidence.
https://jp.mercari.com/item/m70244833979
For a starting point, the PSU is wired rather than modular. While I’ve used many wired PSUs before, today I tend to link with fully wired models, which are usually cheaper and of lower quality. These might range from Tier-D down to Tier-F according to typical ratings.
https://cultists.network/140/psu-tier-list/
The only situation where I buy fully wired PSUs is for compact systems. I’m open to semi-modular options in less important builds, but for critical setups I prefer fully modular units. They’re generally pricier, especially high-end Tier-A models, though they often offer better design and durability.
Returning to your issue, the PSU could still be functioning properly, and the problem might lie elsewhere—such as the motherboard, CPU, RAM, or GPU (which can fail over time). Until you try a different unit, we’ll all have to guess.
Check your warranty details. If it’s only three years, the manufacturer likely expects high replacement costs for components that may fail soon. A short warranty suggests poor quality. Premium Tier-A PSUs usually come with at least a 10-year warranty; some last even longer.
If your PSU is beyond its warranty period, it might still work for another five years—or it could be failing. In that case, consider replacing it with a higher-quality Tier-A unit.
You didn’t provide much information about your PC initially, so we had to work without details.
It’s hard to pinpoint issues remotely unless we have exact part numbers for all major components. Some parts are known to cause problems.
Without precise knowledge of what’s inside your system, we can’t reliably predict its condition. Even though you might not see the importance of these specifics, we’re not testing your machine directly. Please give us a chance.
TLDR: Consider another PSU.
The problem with diagnosing PC faults is that quite often, your first guess is wrong.
I start off changing the "easiest" component I think might be faulty and work my way through the other parts in order of increasing difficulty.
It only takes me 5 minutes to change a PSU, because I have other PCs I can borrow parts from.
There's a good chance your PSU is perfectly OK and the fault lies elsewhere, e.g. in the motherboard, CPU, RAM, GPU or case wiring.
It's also relatively easy to change the GPU and RAM. Swapping CPUs takes a bit more effort because you have to remove the cooler and take care not to bend the pins.
Finally, the last thing I think about is changing is the motherboard. This is usually the most awkward part to replace, because I don't always have a suitable replacement.
All of these component swaps are simply to see if a particular piece of hardware has died. I usually end up returning all the good parts back to the machines I "borrowed" them from.
When I've located the fault, only then do I consider whether or not it's worth replacing the bad part. Sometimes it's just too expensive to replace and I scrap the machine and salvage the good parts for use as spares.
If, as I suspect, you only have one computer, you're in a difficult situation. If you go out and buy a new PSU, chances are the computer still might not start up.
You'll have "wasted" your money on a new PSU if the fault remains.
A far better solution would be to borrow another PSU from a relative or friend. If that's not possible, is there a computer repair shop nearby where they can install a PSU and test your PC?
Better to spend a relatively small amount of money getting a professional to diagnose the fault, than wasting more money trying to track down the fault yourself.
If your motherboard has died, you don't need to buy a new PSU right now. The same applies if your CPU, GPU or RAM have died. All kinds of faults can stop a computer from starting up.
Even if I had your PC in front of me, I still might no be able to locate the faulty component, until I had changed 2 or 3 other parts.
It's a process of elimination and my first guess is not always correct.
Sorry to sound so vague, but fault finding anything with limited information is tricky.
If your PSU had exploded with smoke and flames, I'd be certain it needed replacement. As it is, I'm not sure exactly what's failed in your PC.
Thank you for your feedback! You are absolutely correct! I plan to remove everything except the CPU and clean the contacts. With only a few broken RAM parts, there’s nothing I can replace. I’ll have to visit a professional shop to check the components. The main issue is that the case is the largest available, making it very large, heavy, and difficult to transport on my own. After leaving the hospital, I won’t be able to move much. Hopefully, we can identify the problem soon.
I've moved heavy objects (over 15kg) using a two-wheeled shopping trolley in urban areas on public transport, with the bag removed. A few rubber straps were sufficient. The process took several hours and involved changing trains and buses, though it could be an alternative option.
If not possible, detach all parts from the case, including the PSU, and leave it behind. Always follow ESD (anti-static) precautions—store the motherboard and GPU in separate ESD bags. Carrying a motherboard, GPU, and PSU in a box or bag should be manageable.
A reputable repair shop can test your PC on a workbench. While the case or its wiring might influence performance, if individual components function correctly, you'll identify the issue more easily.
Handle with care. Most gold-plated CPU contacts don’t need cleaning, as gold resists tarnishing unless exposed to extreme humidity or saltwater. Discoloration could indicate overheating.
If necessary, remove the CPU very gently from its socket, inspecting for bent pins with a magnifying glass. Dropping it back in could damage delicate connections.
Cleaning PCs is minimal—usually just blowing dust off cards or removing fans outdoors. Avoid vacuum cleaners for sensitive boards.
Be cautious; improper handling can worsen problems. Only remove CPUs during upgrades or diagnostics. Better safe than sorry—CPUs can be slippery and tricky.
For cleaning, I mostly blow dust off components or clean fans outside. Never use a vacuum on motherboards or PCIe cards.
If you make a mistake, delicate surface mount parts may fall off. It’s safer to avoid damaging them.
Using a brush can generate static charges that harm sensitive parts. Ideally, assembly or cleaning should occur on an ESD-safe workbench; otherwise, a static-free mat and wrist strap are enough. This is the method I use at home.
Psu testers are ineffective and merely useful for verifying a failed psu.
They don’t assess the correct functioning of the device.
If you have doubts about the psu, use a verified replacement with adequate wattage to check performance.
Without reliable psu reviews, check the warranty to gauge its quality.
Three years is outdated, but seven years or longer typically ensures a solid unit.
Thank you for your helpful advice! I was also considering removing the Mobo with cards and PSU if the full case isn't possible. I have a special trolley that I use for carrying my luggage, but after being operated on my hip, it's difficult to move around. We'll see how things go once I'm discharged from the hospital.
This information will help me when choosing my next PSU. I checked the warranty (it was hidden) and it states 3 years.
When I purchase another PSU, I will definitely search for it. I've used it for almost 4 years, working at least 12-16 hours daily each day. It's not too bad after all.