Power supply issues!?

Quick question for you guys

So, last night I had my PC running, and while I was flipping a switch on my power strip, the circuit breaker in my apartment suddenly tripped, cutting all power and killing my computer instantly...
I reset the breaker and tried to boot everything back up, but nothing happened—my rig was just completely dead!
I tried pretty much everything to get it going again, switching to different outlets and even swapping out the power cables, but I got zero luck...
I figured, "Well, looks like the power supply bit the dust," or maybe even the motherboard, so I planned on dropping it off at a repair shop today.

But then I woke up this morning, decided to give it one more shot, and wouldn't you know it? It fired right up on the first try!

Does anyone have any idea what might have caused that little drama, or why it refused to turn on earlier but is acting perfectly fine now?

Daniel Robinson59 said:Anyone have an idea what could cause this? Like, why would it refuse to turn on at first, but then suddenly starts working perfectly fine just like that?

Look, when there's a sudden power outage—maybe even some nasty voltage spikes or oscillations—you end up with leftover static charge sitting in the power supply. It’s probably stuck in some capacitors or transistor circuits. The PSU just refuses to kick in. I don't have the circuit diagrams for the PSU or the motherboard handy, but honestly, this is just what I've learned from doing this enough times.

I usually just pull the actual power cord out from the back of the unit for about ten seconds, then plug it back in.
Most of the time, that does the trick and it actually behaves and boots up when you hit the power button.

But you really have to unplug it directly from the PSU itself. If you just flip the switch on the wall outlet, the impedance from the cable itself keeps affecting the power supply.

I actually pulled the plug on it and let it sit completely disconnected from both the PC and the wall outlet for over half an hour. That’s why I’m still scratching my head about how it suddenly decided to spring back to life this morning like nothing happened.
I mean, unless it just needed a really long time to discharge or something, I honestly have no clue.
But yeah, I’ve definitely never run into anything quite like this before, so I'm curious to figure out what actually went down (and I'm really crossing my fingers that the power supply is actually fine now and didn't sustain some hidden damage in the process).

That happened to me once too; the thing just stayed dead overnight before finally kicking back to life. High-voltage capacitors in a power supply hold onto a charge for way longer than thirty minutes, so they definitely don't just "drain in 10 seconds." Thinking you can jumpstart a PC by just hitting the button is an urban myth—it won't work because those signal pins need stable input and output voltages to be established first. Sometimes you just have to wait (and please, don't go cracking open the PSU to manually drain the capacitors with some load...)
In the other scenario, the PC just wouldn't boot at all. I ended up swapping out the power supply; there must have been some kind of power surge that fried something and obviously killed a protection circuit.

As a precaution, check your voltage rails. Maybe run OCCT to see how it holds up under load (you want to stay within +/- 5% for every voltage), but for everything else, the motherboard will tell the story eventually. There’s no such thing as a magic diagnostic tool.

But let's get back to the actual root cause: did you flip the switch on a power strip and then the breaker tripped?
If that's what happened, that power strip is likely the culprit. Honestly, it's not great for a computer when the current keeps "chattering" through a cheap switch like that. The build quality is usually trash, leading to sparking and messy current flow. Those socket contacts and metal tabs can be pretty pathetic, and modern electronics just aren't built to handle that kind of abuse...
Or maybe look at what else was plugged into that strip. Could something else have caused the breaker to trip? (For example, a laser printer sitting on standby might pull up to 1 kW the second the power kicks in). Something is off there. Your PC issue is probably just a symptom, not the actual cause...

Let me see if I can explain this clearly so you guys get what happened.
So, I have this power strip plugged directly into the wall, and it’s powering my internet router, my monitor, and my desktop computer. Then, I have a second power strip plugged right into that first one, which is where my PS5 and other gear are connected.
The whole thing went sideways when I was shutting down my computer. I reached over and flipped the switch on the second power strip—just trying to turn on the PS5—and the very second I did that, the circuit breaker in my house tripped. I flipped the breaker back on, but then I spent the next hour desperately trying to get my PC to boot up again. Now, look, I’m not some total newbie who doesn't know his way around a computer or how hardware works,
but I even opened up the case to double-check all the connections and gave everything a good vacuuming to clear out any dust... but nothing worked. I couldn't get it running at all until this morning.
To be honest, I paid quite a bit for that specific power strip, probably around $50 or $55, because I really wanted a high-quality setup. Though, looking back, I noticed about two months ago that the switch on it was acting super funky. For instance, when I left for my summer vacation, I tried to turn it off, but the switch wouldn't stay down—it would just pop right back up like it was stuck. Then, as soon as I got back from my trip, it suddenly started working normally again.
But honestly, it feels like there's a serious defect with that switch, so I'm just not going to touch the power button on it anymore; I'll just leave it alone.

Does your PC actually turn on when you plug it straight into the wall? Is the rocker switch on the power supply itself flipped to the ON position?

Daniel Robinson59 said:one quick question

Last night, while my PC was running, I flipped a switch on my power strip and the circuit breaker in my house tripped immediately, killing the computer...

Does anyone have any idea what could have caused that, and why the system refused to boot up at first, only to start working perfectly fine now?

I'll take a shot at this, but I suspect the power strip is the culprit here.

To illustrate, if I were to turn off my power strip right now... and then attempt to flip it back on tomorrow morning—with everything still plugged in—the breaker would trip just like that. Once I reset the breaker, everything functions normally, and this exact scenario has happened to me multiple times already.

The bottom line is that as long as I don't mess with the power strip, everything runs without a hitch. If I were in your shoes, I wouldn't waste my time overthinking this...

Daniel Robinson59 said:one question

Last night, while my PC was running, I flipped a switch on my power strip and the circuit breaker in my house tripped instantly, killing the computer...

Does anyone have any idea what could have caused that, and why it wouldn't turn back on at first, even though it’s working fine now?

Let me take a shot at this; I'm betting the issue lies with the power strip itself.

To give you an example, if I were to shut off my power strip right now, and then try to flip it back on tomorrow morning—with everything still plugged in—the breaker would trip again. Once I reset the breaker, everything functions normally, and honestly, this has happened to me several times already.

The bottom line is that as long as I don't mess with the power strip, everything runs perfectly, so if I were in your shoes, I wouldn't waste any more energy worrying about it...

Most power supplies you see nowadays use both grease and electrolytic capacitors at the input, which causes that huge initial surge of current while the capacitor is charging up. If you've got a bunch of gear plugged into the same power strip, all those startup spikes hit at once, and that’s enough to trip your circuit breaker.

John Cook72 said:when there’s a sudden power outage on the grid (potentially accompanied by voltage spikes or oscillations), some static voltage lingers within the power supply—likely trapped in certain capacitors or transistor circuits—and then the unit simply refuses to kick back in. I don't have the circuit diagrams for the PSU or the motherboard handy, but this is just an observation from practical experience.

I pull the power cord directly from the back of the power supply for about ten seconds, then plug it back in.
Most of the time, it starts working again and responds to the power button normally.

You actually have to unplug it at the source; if you just flip the switch on the wall outlet, the impedance of the cable itself continues to affect the power supply.

The phenomenon you experienced is perfectly normal, but your explanation isn't quite accurate, given that you aren't an electrical engineer. Energy only remains stored in the capacitors, but what happens is that the starting conditions become disrupted, preventing the protection circuit from engaging properly.

Any power supply equipped with a soft-start button rather than a hard kill-switch remains active, albeit at a significantly reduced power state when turned off. It is common knowledge that when things go haywire, as you described, one should unplug the cable from either the computer or the wall outlet for a few seconds to allow the capacitors in the PSU to discharge before attempting a restart.
And please, refrain from mentioning impedance; it is utter nonsense in this context ...as I stated, do not speak on subjects beyond your expertise. With power cables, the contact point is the most critical factor. Inductance, capacitance, and resistance are negligible here. Besides, we are dealing with a frequency of 60 Hz. I assume you are familiar with Omega and its relation to Xc and Xl

If you have actual questions, feel free to ask... there is no prestige to be gained by pretending in electronics.
It is a matter of pure, elegant logic.

wearymason4 said:Modern power supplies utilize both a bridge rectifier and electrolytic capacitors at the input stage. This setup causes a significant current spike during startup while the capacitor charges up. If you have several devices plugged into a single power strip and flip the switch, the combined total of those inrush currents can easily trip a circuit breaker.

🙂 precisely so; you’ve hit the nail on the head, though one should also account for transient phenomena. Every switching power supply employs a bridge rectifier.
Inrush currents can actually exceed the rated maximum consumption by as much as ten times, even if they only persist for a few milliseconds.
Higher-end power supplies often incorporate circuitry to slow down this charging process—specifically the initial filling of the main reservoir capacitor—for the express purpose of mitigating these sudden surges.

Daniel Robinson59 said:I’ll attempt an explanation, assuming it makes sense.
I have a power strip plugged directly into the wall. My computer, monitor, and internet router are all connected to it. Then, another power strip is daisy-chained from that first one, which holds my PS5 and other gear.
The moment I shut down my PC, I hit the switch on the second power strip to turn on the PS5. Immediately, the circuit breaker in my house tripped. After flipping the breaker back on, I spent an hour trying to get the PC to boot—and look, I am certainly no novice when it comes to hardware.
I even opened the chassis to ensure everything was seated correctly, vacuumed out the dust, and double-checked the connections. Nothing worked; I couldn't get it running until this morning.
That specific power strip wasn't cheap; I paid about $50 for it, thinking a high-quality unit would be worth the investment. However, I noticed a couple of months ago that the switch seemed faulty. It wouldn't stay off, for instance, when I left for vacation; it would just spring back without clicking into place. Then, suddenly, after I returned, it started working normally again.
But it seems the issue lies within that switch, so I won't be using the toggle at all moving forward.

Precisely. That is exactly what happened. Switch contacts are often poorly manufactured. When you engage them, the resulting surge can cause arcing, which damages the contacts and creates transients due to poor or incomplete contact. This extends the duration of the surge, which is more than enough to trip a circuit breaker reliably. There is also the matter of timing. Since current follows a sine wave, if you happen to hit the peak of a cycle when engaging the switch, you trigger an enormous current spike. You may have heard old stories about light bulbs exploding under similar conditions; this is essentially the same phenomenon.

Motherboards rarely die simply because a power supply fails. It is highly improbable that the secondary diodes fail that quickly. Usually, the fuse is over-engineered to blow first, or perhaps a transient protection component like a FET or a sacrificial resistor takes the hit instead.😁 (transient - FET) or a protective resistor.

Replacing the switch is a straightforward task and should only cost you about $5.00.

Michael Jackson10 said:The same thing happened to me once; the unit just sat there overnight and then suddenly functioned again. It is a common misconception that high-voltage capacitors in a power supply drain "in 10 seconds" just because you toggle the power button. That is an urban myth. It simply does not work that way due to how the signal pins behave; you have to wait until a stable input and output voltage is established on the lines. Sometimes, one must simply exercise patience—provided, of course, that you aren't opening up the power supply to forcibly discharge a capacitor with a load.
In my other experience, the PC was dead, and replacing the power supply solved it. There was likely a power surge that bypassed the internal protections and fried a component.

Not quite... you absolutely can drain them by toggling the power on the PC to bleed off current. That is precisely how they are engineered. The power supply cannot distinguish whether it is connected to a live grid or not, but it retains enough energy—depending on the capacity and quality of the capacitors—to bridge the gap for a few milliseconds, which is often just enough time for a relay to switch contacts. Some UPS units don't even use relays, but that is a different conversation entirely, much like military-grade circuitry designed to draw almost nothing in standby yet engage the system instantly upon activation.

Michael Jackson10 said:To return to the root cause: did you flip the switch on a power strip and then hear the circuit breaker trip?
If that is the case, that cheap power strip is the culprit. It is hardly healthy for a computer to deal with constant arcing through a low-quality switch. The build quality is abysmal; you get sparking, erratic current flow, and those cheap metal contacts in the sockets are notoriously unreliable. Modern electronics are becoming increasingly delicate.
Alternatively, consider what else was plugged into that strip. Something might have tripped the breaker—for instance, a laser printer in standby mode can pull a massive instantaneous load when it wakes up. Something is fundamentally wrong there. This issue with the PC is merely a symptom, not the primary cause.

🙂 Electronics are sufficiently robust, though we do see a trend toward minimizing that durability. 😉

P.S. ... It eventually powered up because enough micro-arcing occurred during those failed attempts to finally establish a solid electrical contact.