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Turn on computer using power strip
I have my computer plugged in to a power strip.
Is there a way to turn on my computer just by powering on the power strip instead of having to hit power button on computer? Thanks, Andy "It's always too early to quit." |
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Turn on computer using power strip
Andy wrote:
I have my computer plugged in to a power strip. Is there a way to turn on my computer just by powering on the power strip instead of having to hit power button on computer? Thanks, Andy "It's always too early to quit." There can be a BIOS power policy setting on desktop motherboards, which allows booting as soon as the power is restored. It goes something like this: "When the power is restored" [Keep computer off] == typical default [Start computer] == what you want [Last state] == put computer OFF or ON depending on whether it was previously OFF or ON at the instant the power dropped (mostly useless setting). Some motherboards and their chipset, have actual support. There won't be any "computer twitching" or "fake starts" to figure out what power state to use. The computer instantly responds according to that BIOS setting. On motherboards where the chipset doesn't really support the feature, the feature is emulated. On power recovery, the computer *always* comes on for at least one second. In that one second, the computer checks the BIOS setting. It can then decide what to do after that. On some computers, you get "power on, power off, power on" as the sequence at startup, as stuff like the above happens. Some people assume their computer is busted when it behaves like that, but it's actually caused by the need to emulate that feature. Paul |
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Turn on computer using power strip
On Fri, 20 Jul 2018 21:10:33 -0700 (PDT), Andy
wrote: I have my computer plugged in to a power strip. Is there a way to turn on my computer just by powering on the power strip instead of having to hit power button on computer? Thanks, Andy "It's always too early to quit." The answer is in the BIOS under the Power settings. They usually have a setting that either powers up every time power is restored or returns to the state it was in when you shut it off. XP tends to tolerate dumping power and restarting from pulling the plug better than W/7. My tiki bar MP3 PC runs this way and it is a little cranky when I put a 7 machine out there. |
#4
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Turn on computer using power strip
On Sat, 21 Jul 2018 00:43:39 -0400, Paul
wrote: Andy wrote: I have my computer plugged in to a power strip. Is there a way to turn on my computer just by powering on the power strip instead of having to hit power button on computer? Thanks, Andy "It's always too early to quit." There can be a BIOS power policy setting on desktop motherboards, which allows booting as soon as the power is restored. It goes something like this: "When the power is restored" [Keep computer off] == typical default [Start computer] == what you want [Last state] == put computer OFF or ON depending on whether it was previously OFF or ON at the instant the power dropped (mostly useless setting). Some motherboards and their chipset, have actual support. There won't be any "computer twitching" or "fake starts" to figure out what power state to use. The computer instantly responds according to that BIOS setting. On motherboards where the chipset doesn't really support the feature, the feature is emulated. On power recovery, the computer *always* comes on for at least one second. In that one second, the computer checks the BIOS setting. It can then decide what to do after that. On some computers, you get "power on, power off, power on" as the sequence at startup, as stuff like the above happens. Some people assume their computer is busted when it behaves like that, but it's actually caused by the need to emulate that feature. Paul Back in the early days of ATX supply before the BIOS got smart enough to start on power restore but it still needed a start signal my hack was a 5v or 12v relay with the N/C contact connected to the power on switch (to ground) When power comes up it sees "power on" and as soon as the supply comes up the power on shot goes away. Simply grounding pin 14 might not work. |
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Turn on computer using power strip
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#6
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Turn on computer using power strip
On Sat, 21 Jul 2018 02:21:55 -0400, Paul
wrote: wrote: On Sat, 21 Jul 2018 00:43:39 -0400, Paul wrote: Andy wrote: I have my computer plugged in to a power strip. Is there a way to turn on my computer just by powering on the power strip instead of having to hit power button on computer? Thanks, Andy "It's always too early to quit." There can be a BIOS power policy setting on desktop motherboards, which allows booting as soon as the power is restored. It goes something like this: "When the power is restored" [Keep computer off] == typical default [Start computer] == what you want [Last state] == put computer OFF or ON depending on whether it was previously OFF or ON at the instant the power dropped (mostly useless setting). Some motherboards and their chipset, have actual support. There won't be any "computer twitching" or "fake starts" to figure out what power state to use. The computer instantly responds according to that BIOS setting. On motherboards where the chipset doesn't really support the feature, the feature is emulated. On power recovery, the computer *always* comes on for at least one second. In that one second, the computer checks the BIOS setting. It can then decide what to do after that. On some computers, you get "power on, power off, power on" as the sequence at startup, as stuff like the above happens. Some people assume their computer is busted when it behaves like that, but it's actually caused by the need to emulate that feature. Paul Back in the early days of ATX supply before the BIOS got smart enough to start on power restore but it still needed a start signal my hack was a 5v or 12v relay with the N/C contact connected to the power on switch (to ground) When power comes up it sees "power on" and as soon as the supply comes up the power on shot goes away. Simply grounding pin 14 might not work. Well, grounding pin 14 will work, because it's wired-OR logic. The motherboard uses open collector drive. You can't damage the motherboard by shorting pin 14 to ground. (Not unless a motherboard designer violates the rules.) The trick is, to decide when to stop driving pin 14 like that. I don't know if an OS like Windows 10, puts up a "it is safe to turn off your computer" like in Win98 days, to indicate it's OK to drop pin 14. You don't want to drop pin 14, until all caches are flushed. And you don't need a relay for pin 14 - if you want to do your own circuit, you can do open collector drive on your circuit too. In the old days, for reasons I don't understand, they used to use powerful open collector drivers. Like a 74F series (74F38?) with 64mA drive. Yet the pullup resistor on pin 14 isn't supposed to source more than a couple milliamps. And the other observation is, we seem to have motherboards where the OC driver fails, more than it should. So either the notion it's a couple of milliamps isn't always right, or the designers of systems 20 years ago were nuts :-) PS_ON# has always been a bit weird that way. Certainly with your idea of using a relay, you should always "win". I think modern designs use less potential drive on PS_ON# than the design from the old days. There was some kind of OC driver that I've forgotten the number now, but it had sufficient drive to drive a doubly terminated 50 ohm transmission lines. That's how I buffered clocks on a board with a lot of discrete clocks. Four of those, one per quadrant. So in terms of drivers for the PS_ON#, we don't lack for "gorilla" chips to do the job. The idea of using 8mA drive is so... yesterday. There is a chip which will drive a 2 amp load, but it's not OC, so would be inappropriate for the job. I never got one of those for eval though - would have been fun to play with. That was a CMOS chip where the circuit wasn't even considered a logic gate, more like an amplifier with a gain of 0.9 or so (the output amplitude is slightly smaller than the input signal). Paul For some reason the machine I was working on would not run if I just jumpered pin 14. It powered up but it did not work. I suspect the BIOS really wants to see the power button pressed and released. The relay on the power button circuit fixed that. |
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Turn on computer using power strip
On Friday, July 20, 2018 at 11:43:42 PM UTC-5, Paul wrote:
Andy wrote: I have my computer plugged in to a power strip. Is there a way to turn on my computer just by powering on the power strip instead of having to hit power button on computer? Thanks, Andy "It's always too early to quit." There can be a BIOS power policy setting on desktop motherboards, which allows booting as soon as the power is restored. It goes something like this: "When the power is restored" [Keep computer off] == typical default [Start computer] == what you want [Last state] == put computer OFF or ON depending on whether it was previously OFF or ON at the instant the power dropped (mostly useless setting). Some motherboards and their chipset, have actual support. There won't be any "computer twitching" or "fake starts" to figure out what power state to use. The computer instantly responds according to that BIOS setting. On motherboards where the chipset doesn't really support the feature, the feature is emulated. On power recovery, the computer *always* comes on for at least one second. In that one second, the computer checks the BIOS setting. It can then decide what to do after that. On some computers, you get "power on, power off, power on" as the sequence at startup, as stuff like the above happens. Some people assume their computer is busted when it behaves like that, but it's actually caused by the need to emulate that feature. Paul I set it to always on. But it doesn't work. I realized my computer is plugged into an APC. So in effect, it always has power to it. If I turned the APC on and off, I would have to listening to it's beeping. Andy |
#9
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Turn on computer using power strip
In message , Paul
writes: [] The front button does not have "direct effect". It's a [partially] software mediated button. The switch on the back of the PSU, is a direct effect switch that cuts the mains. If it's there; not all power supplies _have_ the back panel rocker switch. (Or have regulations changed and they have to nowadays?) [] the schematic. There's a 4.7K resistor to +5VSB and there would be 1 milliamp sunk to ground on the motherboard end of PS_ON# pin 14. [] Or slightly over 1 mA, of course. Isn't it funny that resistors (and capacitors, and many inductors) are still made to the E12 series, which dates from when they were sorted into bins as they came out of the machine that made them, whereas they're usually precision-made to 2% or even 1% these days! -- J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf aibohphobia, n., The fear of palindromes. |
#10
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Turn on computer using power strip
Someone told me it was a bad idea to everything on from a power strip.
Is this true? Andy wrote: I have my computer plugged in to a power strip. Is there a way to turn on my computer just by powering on the power strip instead of having to hit power button on computer? .... -- Quote of the Week: "Better (to be) an ant's head than a lion's tail." --Armenian and Maltese Note: A fixed width font (Courier, Monospace, etc.) is required to see this signature correctly. /\___/\Ant(Dude) @ http://antfarm.home.dhs.org / http://antfarm.ma.cx / /\ /\ \ Please nuke ANT if replying by e-mail privately. If credit- | |o o| | ing, then please kindly use Ant nickname and URL/link. \ _ / ( ) |
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Turn on computer using power strip
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#12
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Turn on computer using power strip
J. P. Gilliver (John) wrote:
In message , Paul writes: [] The front button does not have "direct effect". It's a [partially] software mediated button. The switch on the back of the PSU, is a direct effect switch that cuts the mains. If it's there; not all power supplies _have_ the back panel rocker switch. (Or have regulations changed and they have to nowadays?) [] the schematic. There's a 4.7K resistor to +5VSB and there would be 1 milliamp sunk to ground on the motherboard end of PS_ON# pin 14. [] Or slightly over 1 mA, of course. Isn't it funny that resistors (and capacitors, and many inductors) are still made to the E12 series, which dates from when they were sorted into bins as they came out of the machine that made them, whereas they're usually precision-made to 2% or even 1% these days! It's a pullup resistor. Just an order of magnitude of current flow is required in a discussion of such. You could use a 4.7K 5% or a 5.1K 5% and nobody would know the difference. I'm feeling nostalgic now, for my TI Bible... It probably had the equations spelled out for working out what pullup to use :-) [It would involve a discussion about wired-OR logic using open collector drive, N outputs wired to M inputs, and what pullup resistor is required.] In this case N=1 and M = approximately 1. https://cdn.eeweb.com/articles/artic...web-dsl-01.jpg And switching a 1mA current flow with a relay, may not provide enough current to keep the relay contacts clean. Relays have a maximum current, but they also have a minimum current flow they can handle if you expect the contacts to remain clean and trouble-free. Even with a precious metal coating there will still be a minimum current flow spec. I might go looking for a reed relay to do it perhaps. Rather than the contactor off an air conditioner. Contact bounce ? Not a problem driving the front panel Power button. Might need to think about the consequences of driving pin 14 with such. This is why semiconductor drive is "nicer". And in this case, you could use an optoisolator to close the contacts if you wanted. Paul |
#13
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Turn on computer using power strip
Ant wrote:
Someone told me it was a bad idea to everything on from a power strip. Is this true? Andy wrote: I have my computer plugged in to a power strip. Is there a way to turn on my computer just by powering on the power strip instead of having to hit power button on computer? Take the "average" electrical device for a moment. Plugging the device into the wall, applies mains to it instantly. Flipping the switch on the power strip, applies mains to it instantly. There is no difference from that perspective. A switching power supply needs an inrush limiter in any case, to help limit the flow of mains current at T=0. Without some sort of limitation, the bridge rectifier could blow out. On a typical ATX supply, this number can actually amount to 40 amps or 80 amps for the first cycle. A secondary effect of connecting certain ATX supplies, is it "makes your UPS beep", as the inrush is so large, the UPS mis-interprets the load as an "overload" condition. (It's the combination of current flow level and the time the overload is present, that determines whether the UPS will beep. Hitting 80 amps for a microsecond, hurts nothing.) I have one ATX supply here, my Sparkle supply, which causes the UPS to beep no matter how the Sparkle gets connected to mains. ******* If switching a power strip with nothing but wall warts, there is little to worry about. However, if a PC is on the power strip, wait 30 seconds for +5VSB to drain. This allows the motherboard to enter an "uninitialized" state electrically, so that the next startup is nice and clean, and all the logic starts from an "unpowered" state. The other time constant involved, is the time for the inrush limiter NTC resistor to cool off. It normally runs hot, and in the hot state, has low resistance. In the cold state, it has high resistance. If you wait 60 seconds after flipping the power strip off, the NTC cools off, the resistance is high, and the charging current into the main cap uses a lower current flow value as a result. The UPS is less likely to beep. Once the NTC resistor heats up, the resistance drops, and the NTC resistor becomes "more efficient" for running during the rest of the session. To make the NTC run hot, wastes a tiny bit of electricity during normal operation. Summary: Wait 60 seconds after power strip "flip off", before your next "flip on". *Do not* toggle the living daylights out of it. Try not to make a stroboscope using your power strip switch. It can actually cause an ATX power supply to "blow" if you do that. A poster in one of the hardware groups managed to do that :-) That's how we know "what the consequence of being an idiot" are :-) If you treat the switch with some respect, there is no reason to fear it. Paul |
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Turn on computer using power strip
Ant,
Someone told me it was a bad idea to everything on from a power strip. Is this true? (the below is an answer to the above, switching ON. Swiching off by it has got its own, and already described, problems) It depends. On what ? On how your computers power supplies respond to it. In the old days there was little done about the so-called "inrush" current (the current a power supply could draw in the first few mSec its turned on - which can be a number of times its normal one), and as such a few of such power supplies together could reasily excess a classic fuses maximum spike current, and blow out. Nowerdays with all those (slow!) automatic fuses and (computer) power supplies that are protected agains the effects of inrush current its not as much as a problem anymore. In my case I've got at least four PCs and a laser printer on the same power strip (as well as several power warts, some feeding routers) which I'm using every day (on in the morning, off in the evening), and have never had a problem with it. Regards, Rudy Wieser "Ant" wrote in message ... Someone told me it was a bad idea to everything on from a power strip. Is this true? Andy wrote: I have my computer plugged in to a power strip. Is there a way to turn on my computer just by powering on the power strip instead of having to hit power button on computer? ... -- Quote of the Week: "Better (to be) an ant's head than a lion's tail." --Armenian and Maltese Note: A fixed width font (Courier, Monospace, etc.) is required to see this signature correctly. /\___/\Ant(Dude) @ http://antfarm.home.dhs.org / http://antfarm.ma.cx / /\ /\ \ Please nuke ANT if replying by e-mail privately. If credit- | |o o| | ing, then please kindly use Ant nickname and URL/link. \ _ / ( ) |
#15
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Turn on computer using power strip
R.Wieser wrote:
Ant, Someone told me it was a bad idea to everything on from a power strip. Is this true? (the below is an answer to the above, switching ON. Swiching off by it has got its own, and already described, problems) It depends. On what ? On how your computers power supplies respond to it. In the old days there was little done about the so-called "inrush" current (the current a power supply could draw in the first few mSec its turned on - which can be a number of times its normal one), and as such a few of such power supplies together could reasily excess a classic fuses maximum spike current, and blow out. Nowerdays with all those (slow!) automatic fuses and (computer) power supplies that are protected agains the effects of inrush current its not as much as a problem anymore. In my case I've got at least four PCs and a laser printer on the same power strip (as well as several power warts, some feeding routers) which I'm using every day (on in the morning, off in the evening), and have never had a problem with it. Regards, Rudy Wieser There are two ways to handle inrush. NTC thermistor is the old way. Runs hot under normal operation, starts out "cold" to work properly at the application of mains power. The new way, is a side effect of the Active PFC controller. It's possible as the power supply starts, to use the active PFC controller in a series pass mode, for the purposes of limiting inrush. After a suitable (short) interval, it becomes line interactive as it attempts to make the voltage and current waveforms "in sync", dropping the power factor to unity. (Older power supplies have a power factor of 0.65, and current is not in phase with voltage. In addition, the current waveform isn't a sinusoid any more either and has a harmonic content.) Someone mentioned power supplies with no switch on them. My old Mac G4 works that way. It has no switch. After a short delay after plugin, you hear a relay engage. Presumably the interval between the two events, allows for a "slow charging" of the main capacitor. So that, not even the relay gets ripped to shreds by the inrush. We had an inrush problem with a product at work, and the responsible manager placed a *40amp* relay between the mains and the (poorly designed third party) PSU. The 40amp rating would be sufficient to "take inrush forever", and there were never any reports of trouble with the relay based design. It also made a satisfying "clunk" noise at startup. There was a rather large retail power supply reviewed at Anandtech in the last year, and (apparently) the company that designed it "forgot" to put any kind of inrush solution in it. Anandtech reported that the breaker in their breaker panel tripped, each time the supply was powered up. Now, I want one of those, because I haven't really tested the breakers in my panel for some time. Paul |
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