What's a turned-off power supply doing?

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Hawaii Cruiser's picture
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What's a turned-off power supply doing?

There's someone on eBay who sells G4 power supplies that she has refurbished. She says she has improved them thusly: "As a way to improve the power supply an additional circuit was installed. This extra circuit turns the fan on as soon as you connect the power supply, so even with the computer off, your fan will work, keeping the temperature of its internal components from overheating. In case you didn't know, your power supply is hard at work, even with your computer off." So what is a power supply hard at work doing when it's turned off? My computer setups that I regularly turn off I turn off by turning off the surge suppressor power strips they're connected to (after shutting down, of course). So I'm also turning off whatever the power supply is doing when the computer's shut down. Is there any reason to keep the power to the power supply live when the computer's shut down?

I've got a Sony Vaio tower that I found discarded, and at first, I thought it had a bad power supply because when I tried starting Windows the boot would stop and I'd get a hardware error message that said I should check Power Setup for problems (" Hardware Monitor found an Error. Enter Power Setup menu for details "). I'd look in Power Setup and not see anything significant, so instead, I'd command ignore after the error, and it would go ahead and boot Windows just fine, but it would do the error stop every time I turned the computer on subsequently--but I was unplugging the machine when I wasn't using it. I've now found that if I leave the machine plugged in--shut down but plugged in to a live power outlet--it will start up just fine without the error stop. Is this a capacitor thing? thanks

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i have a vaio and i will get

i have a vaio and i will get that message if the fan isnt spinning fast enough.

Jon
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Er, on machines with softpowe

Er, on machines with softpower they produce the trickle current the keeps the circuits monitoring the power button going. And, the trickle power also keeps the clock/CMOS/PRAM battery from being used while the machine is off. If the machine has softpower, it's probably best to leave it on at the power strip. Machines with hard power switches shouldn't matter.

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The trickle is minimal, so th

The trickle is minimal, so the "working hard" statement you came across is so much bantha poodoo.

That said, I've read the cumulative drain of soft-power appliances and wall-warts is claimed to be an appreciable amount of total US power consumption.

So...save a bit of power by cutting the power at the power bar, and the trade-off is shorter cmos/pram battery life.

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Yeah, I try to keep all my wa

Yeah, I try to keep all my wallwarts on some kind of power supply I can turn off. I've even put switches on extension cords so I can turn them off. I heard a PSA on the radio yesterday for the first time that suggested people unplug their power adapters when not it use, so I guess that message is finally going into the airways.

Rigging a G4 powersupply so that the fan keeps going after shutdown sounds unnecessary, though, doesn't it?

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Re: Yeah, I try to keep all my wa

Rigging a G4 powersupply so that the fan keeps going after shutdown sounds unnecessary, though, doesn't it?

Sounds to me that someone was trying to fix a bad power supply and this was the only way to make it work. So in order to try to sell it they turned it into a "feature". That is the silliest thing that I have ever heard. There is no reason you need to keep the fan running when the computer is not on. The power supply isn't doing anything (except for the trickle current for the on/off button).

IC

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