Okay, this has happened to me twice, with two separate PC's.

I always switch off my PC at the wall when not in use, not during the day, but certainly over night.

1. About 6 years ago:

Occasional loud pop/crack noise, that I felt was coming from UK 13 amp wall socket. Being handy with home electrics, I replaced the socket.  No dice, still happened. Happened again, and seemed to kill surge protector strip, thinking that was the issue, I replaced it. Nope, still happened intermittently. Then finally, it happened again and the PSU was dead. RMA'd the PSU and all was well. That was it, faulty PSU. But couldn't figure out how the noise seemed to be coming from the wall socket, not the back of the PSU and why it didn't trip the RCD in the consumer unit, or the fuse in the plug.  But anyway, all was now well. PSU replaced, issue gone. 

Fast forward to 2023, no longer in the UK, different house, different country, different PC... same again, now getting very loud pop when I turn the PSU on at the wall socket. PC itself fires up without any issue when I hit the case on switch, and all seems well. However as this was how the issue stared 6 years ago, I'm suspecting another failed PSU.

Reading around on the internet, I came across a Johnny Guru contribution on a forum, in regard to somebody having the same issue. Johnny Guru, PSU expert now working for Corsair, was claiming that its better to leave the PSU switched on at the mains socket, and the switch on the back of the PSU on too, and just shut down in Windows, so that the hefty capacitors in modern PSU's stay partially charged. His claim is that if you switch off at the wall, the capacitors are fully discharged, so when you switch back on the following day, there's a sudden inrush of current into the capacitors, hence the load pop and hence more wear and tear.

I'm not a fan of leaving any appliance plugged into the mains, switched on, to be honest, but what about you guys, have you come across this issue before, and what do you do, do you leave the PSU plugged in and switched on at the mains, and just shut down the PC and monitor, or do you switch off at the wall outlet too?

 

 

HI Martin,

I run water cooling so my computer only runs when I actually use it. As I only use it a few hours a week there is less wear on the water pump. I simply shut the computer down through windows and that's it.

However, IF there is a thunderstorm OR I travel out of town for the week I will switch the power supply off so there is no power running through the system. This has always worked for me, but I would see no reason to switch or unplug your system every time you are done using it for the day. Just my thoughts.

As a side note.. I also turn off any power strips in my theater room during a storm as I don't want to damage my receiver or TV. But in Oregon these don't happen too often. 2x a year maybe.

Over the last 5 years I've killed one wall socket, two smart plugs and one PSU while attempting to be green by switching power on/off to my computer. In the end, I think I've created more e-waste and more fire hazards (two of these events caused spectacular sparks and burning smells) by doing this, so now I just shutdown my PC with Windows and leave it at that.

Edited March 13, 20233 yr by Reset XPDR

Maybe it's a 220v thing...here in the US on 115v power I've used switched UPS/surge protectors to isolate computers when not in use (we get hellacious lightning storms here in the Colorado high country).  Never ever had a PSU complain when power was disconnected or re-energized.  Could be having input line voltage in the middle of the PSU's input range helps mitigate out-of-spec voltage spikes associated with inrush surges.

9 hours ago, Bob Scott said:

Maybe it's a 220v thing...here in the US on 115v power I've used switched UPS/surge protectors to isolate computers when not in use (we get hellacious lightning storms here in the Colorado high country).  Never ever had a PSU complain when power was disconnected or re-energized.  Could be having input line voltage in the middle of the PSU's input range helps mitigate out-of-spec voltage spikes associated with inrush surges.

 

230 volts now in the UK. Used to be 240.

Thing is, I've owned numerous PSU's, in multiple rigs. Only had this issue twice now and both EVGA PSU's. All of them have been switched off at the mains socket at night. My son still has one of my old Enermax PSU's in the PC I gave him, old PSU, I'd guess 10 years. He does the same, off at the wall at night. No issues, long lifespan, still doing fine. So I'm not sure I buy this theory from Johnny Guru that the extremely loud pop is normal, as a result of inrush current. When I say loud, it literally makes you jump out of your skin.

In my opinion, a product like a PSU in a PC, should be capable of being powered up and down without issue, and without a detonation threatening to bring the house down. And it should be able to do so for the expected life of the product.

The PC that had this issue 6 years ag, had a new PSU via RMA and continued to faction perfectly until recently, no issues despite being switched off at the wall at night.

 

I'll drop EVGA an email and see what they have to say.

Edited March 14, 20233 yr by martin-w

11 hours ago, Reset XPDR said:

Over the last 5 years I've killed one wall socket, two smart plugs and one PSU while attempting to be green by switching power on/off to my computer. In the end, I think I've created more e-waste and more fire hazards (two of these events caused spectacular sparks and burning smells) by doing this, so now I just shutdown my PC with Windows and leave it at that.

 

That's weird. Something very mysterious going on there.

For me, its not about being green. And I know its the low power transformer in the PSU that takes over when the PC shuts down, but PSU still on at wall and PSU switch, for me, Is one more device that still getting power and one more device that poses a theoretical fire risk. Some things have to be left on of course, but I like to keep them to the minimum. 

 

Perhaps it varies from PSU to PSU.
For years, I had one that would always arc when re-attaching the power cable after routine cleaning.
It never failed, but was always slightly alarming when it happened.
The last two, however, unplug and plug without incident.
I did once drop a motherboard battery, by mistake, into a disconnected PSU.
That did indeed make a loud noise and the PSU stopped working.
Proof, if proof were needed, that disconnected or unplugged, does not mean that there is no electricity
in there.

3 hours ago, Reader said:

Perhaps it varies from PSU to PSU.

 

In this case, as it happens every time, every morning I switch on at the wall socket, it suggests to me that the inrush thermister isn't doing its job. 

The inrush thermistor is designed to prevent this.

In my case, the PSU  is less than a year old, and figuring in extended periods off for holidays, I would think its been cycled less than 300 times. And in my opinion, its not much of a thermistor if it cant handle 300 cycles. 

 

 

Edited March 14, 20233 yr by martin-w

3 hours ago, Reader said:

For years, I had one that would always arc when re-attaching the power cable after routine cleaning

 

Are you in the US? Do you have switches on your wall outlets? If not, I can see how there would be the occasional arching. We get it with our wall outlet switches sometimes, you flip the switch and there will be an occasional blue/green flash, quite normal with higher load appliances. Often with Switched Fused Connection Units, spurs to an appliance.

 

I haven’t turned off any of my computers at the wall in years. The only time power is disconnected to them is during a power cut. Thankfully very rare here.

The only time I’ve had a PSU fail was back in the 90s and the very loud bang made me jump out of my skin.

I always buy the Gold version of the PSU.

26 minutes ago, Ray Proudfoot said:

I haven’t turned off any of my computers at the wall in years.

The only time I’ve had a PSU fail was back in the 90s

 

Thanks Ray. That would back up the Johnny Guru claim that its the best option for PSU inrush thermistor lifespan. If that's true though, and it can't even handle, less than 300 cycles, then the PSU manufacturers should make it known that PSU's should be left on at the wall.

It certainly could be that I'm being too paranoid regarding the small fire risk associated with leaving it on at the wall. 

I'll try an experiment tomorrow morning. Leave it on at the wall tonight, hit the case power button the following morning and see what happens. I have heard of some people still getting the issue, but with that scenario, at the power button.

To be honest though,. if the inrush thermistor is doing this, I'll probably still RMA it, even if I decide to do what you do, and leave on at the wall. 

Edited March 14, 20233 yr by martin-w

26 minutes ago, martin-w said:

 

Thanks Ray. That would back up the Johnny Guru claim that its the best option for PSU inrush thermistor lifespan. If that's true though, and it can't even handle, less than 300 cycles, then the PSU manufacturers should make it known that PSU's should be left on at the wall.

It certainly could be that I'm being too paranoid regarding the small fire risk associated with leaving it on at the wall. 

I'll try an experiment tomorrow morning. Leave it on at the wall tonight, hit the case power button the following morning and see what happens. I have heard of some people still getting the issue, but with that scenario, at the power button.

To be honest though,. if the inrush thermistor is doing this, I'll probably still RMA it, even if I decide to do what you do, and leave on at the wall. 

Here in South Africa, we are blessed with a wonderful arrangement called "Load shedding". This is imposed on us by the National energy provider to minimise the risk of a national blackout, due to there being insufficient capacity in the National Grid. As a result, power will go off following a published schedule, which varies according to the available power nationally.

Currently, we are on a schedule that cuts power for 2 periods of 2 hours each a day. (Spread over 24 hours, so could be in the night). Not very helpful for long overnight flights.

However, my point is that I just turn off the PC with Windows and turn off the monitors, before the cuts. I do not touch the wall switches at all and nothing has gone wrong in about 2 years. Even if I forget and the power just goes, the PC has started up again with no problems.

I just keep my router on with a mini UPS which works well.

1 hour ago, martin-w said:

It certainly could be that I'm being too paranoid regarding the small fire risk associated with leaving it on at the wall. 

I can understand the logic of turning computers off but consider the other items in your house that remain on constantly. Router, fridge, freezer, TV, microwave etc. etc. Many things are designed to be left on permanently. My Naim amplifier draws 0.001 watts in standby so I leave that alone too.

Gold PSU? You didn't say.

40 minutes ago, Ray Proudfoot said:

I can understand the logic of turning computers off but consider the other items in your house that remain on constantly.

 

Yep, exactly, Its just one more thing that I don't have to leave on. I keep them to the minimum if I can.

I have to say, after numerous PSU's over the years, this has happened twice, so I've not really had an issue turning off at the wall with the the majority of PSU's I've owned. Two EVGA's, that's it, in many years. 

 

Quote

Gold PSU? You didn't say.

 

EVGA 1000 Gold+ I don't believe the efficiency is relevant though. Unless the more efficient PSU's have uprated thermistors of course. Can't recall what the PSU that failed 6 years ago was. Come to think of it, it was probably longer than that. 850 watt I recall. 

I've contacted EVGA, will be interesting what they say. 

1 hour ago, IanHarrison said:

However, my point is that I just turn off the PC with Windows and turn off the monitors

 

Be interesting to do a poll.  

Edited March 14, 20233 yr by martin-w