Timeline for What happens when hardware tries to draw more power than power supply can provide?
Current License: CC BY-SA 3.0
15 events
| when toggle format | what | by | license | comment | |
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| May 1, 2017 at 15:44 | audit | First posts | |||
| May 1, 2017 at 15:45 | |||||
| Apr 24, 2017 at 9:36 | comment | added | Chris H | Note that overload is a function of time as well as current -- many PSUs (including the last couple of ATX ones I bought) have a maximum continuous and a maximum peak rating. The latter gives you a bit of spin-up leeway without the voltage dropping, but if sustained too long the PSU should trip (e.g. a thermal fuse). Antex argue against this, but the issue is really when people spec to the peak as if it were the continuous. | |
| Apr 24, 2017 at 0:16 | comment | added | Jamie Hanrahan | Then it didn't "crowbar", which is the condition from which you do have to remove all power for a bit. Likely it just dropped POWER_OK, so the mobo stopped asserting ~PWR_ON. | |
| Apr 23, 2017 at 2:15 | comment | added | psusi | @JamieHanrahan, It has been a good many years since I shut down my system by accidentally shorting the molex connector plugging in an optical drive while the system was on ( firmware hung from time to time and it needed power cycled to bring it back ), but I didn't have to unplug it -- just push the power button to turn it on again. | |
| Apr 22, 2017 at 22:16 | comment | added | Jamie Hanrahan | Shrug. I always have. | |
| Apr 22, 2017 at 22:10 | comment | added | Yet Another User | @JamieHanrahan I have a lab PSU based on an old ATX one and I do not have to unplug it from the wall, only cycle the PS_ON signal. | |
| Apr 22, 2017 at 17:00 | comment | added | Dietrich Epp | @kasperd: The comment wasn't an attempt to "invalidate" anything you wrote. | |
| Apr 22, 2017 at 14:50 | comment | added | stannius | I had a computer in the late 90s that was under-supplied. Every morning a 2 AM a disk indexing job kicked off, and it would reboot. I didn't have to remove the power cord for 10 seconds though. | |
| Apr 22, 2017 at 10:55 | audit | First posts | |||
| Apr 22, 2017 at 10:55 | |||||
| Apr 22, 2017 at 5:01 | comment | added | Dietrich Epp | @kasperd: There are other intermediate regulators between the power supply and the digital logic. | |
| Apr 21, 2017 at 23:40 | comment | added | kasperd | @user1306322 It is plausible that you can find power supplies which don't have such protection and you would just see a voltage drop. If no other safety precautions are in place and the voltage drops too far the voltage difference between zeros and ones will diminish and data will get corrupted. | |
| Apr 21, 2017 at 21:47 | comment | added | Jamie Hanrahan | Indeed, this is part of the ATX power supply spec. I believe it was in the AT power supply spec as well. To use the supply again you will need to remove AC power completely (unplug it...or if it has a hardware power switch on the back, flip that to off) for 10 seconds or so, to discharge a capacitor. Then restore power. | |
| Apr 21, 2017 at 21:01 | comment | added | David Schwartz | I can't speak to every power supply ever, but this is what happens on typical desktops and servers based on standard PC designs. | |
| Apr 21, 2017 at 20:53 | comment | added | user1306322 | Does this happen with every power supply ever, or are there different scenarios for old/new, desktop/server supplies? | |
| Apr 21, 2017 at 20:52 | history | answered | David Schwartz | CC BY-SA 3.0 |