pc won't wake up from sleeep mode
December 4, 2016 4:56 AM   Subscribe

My pc does not wake from sleep mode. This started yesterday: I move the mouse or hit return, the computer starts, the start button stops flashing, and then nothing. The monitor says it receives no input. I have to unplug the machine and then push start button. What should I do?

This used to happen once every few months, but this weekend it has happened every time the computer goes to sleep (n=6). These are the control panel settings: Sleep after: 60 minutes ; Allow hybrid sleep: off ; Hibernate after: never ; Allow wake timers: "setting: enable". (I changed hybrid sleep yesterday from on to off; changed "sleep after" this morning; I don't know what wake timer is.) Yesterday when I would unplug, the computer revived slowly but acted like it was waking from sleep; today however it acted like it was shut down improperly. It is an acer desk top pc, windows 7, a few years old. The computer is fine except for this. (Is a solution to set "sleep after" to "never"? Or to shut down each time I walk away?) I've looked online, but not sure how to proceed after adjusting the control panel. I appreciate your suggestions. Thank you in advance.
posted by philfromhavelock to Computers & Internet (12 answers total) 2 users marked this as a favorite
If it used to do this occasionally and now does it all the time, that feels like a deteriorating power supply to me. I've seen quite a few power supply failures in older Acer Veriton S460 desktop machines and similar models built around Acer's 11 litre case and PSU, and yours is a good description of the symptoms caused by that.

I changed hybrid sleep yesterday from on to off ... Yesterday when I would unplug, the computer revived slowly but acted like it was waking from sleep; today however it acted like it was shut down improperly

That's expected behavior, if what's actually happening is that the computer is failing to power up properly after being suspended.

Hybrid sleep is effectively a hibernation with the very last step (full power down) missing, so that if the computer stays powered up (but sleeping) it can still wake as quickly as it would do from a plain non-hybrid sleep, but if the power goes away while it's asleep it will start up from the hibernated state instead. That looks very much like waking from sleep only slower.

Turning hybrid sleep off means that you don't get a hibernated backup of the sleeping state, so when that sleeping state is lost due to forced power cycling, cold-start sees a computer that was simply never shut down properly.

The only reason you might want to turn hybrid sleep off is that writing out the hibernated system state takes a tiny bit longer than not doing that. However, most of the time it doesn't matter how long it takes to go from active to sleeping so I'd recommend turning hybrid sleep back on. That will minimize the likelihood of disk corruption until you can get the power supply replaced.
posted by flabdablet at 5:23 AM on December 4, 2016

Thanks for the answer! I appreciate it.

I changed back to hybrid sleep.

Is this something I could change on my own? Can I buy replacement power supply and connect it or should I call someone in? (I don't know anything about computer hardware, so I glanced at wikipedia entry for power supply.)
posted by philfromhavelock at 5:59 AM on December 4, 2016

It's not as hard as opening up a Macbook or the like - physical removal and replacement isn't that tough, but the challenges are

a) making sure the replacement fits physically and has the capacity you need.
b) making sure all the myriad connectors to various components inside the case are connected back to the right spots.

It's generally easier if it's a "generic" PC - name brands like Dell and HP seem to go out of their way to use proprietary connectors, sizes, etc., so sourcing the part gets a little harder.
posted by randomkeystrike at 6:09 AM on December 4, 2016

It should not be too hard to replace. I would unplug the machine, open the thing up, locate the power supply (easy peasy... it's where the power cord goes in) and take some good clear pictures so you'll know how to put everything back. Then unscrew things until you can remove the power supply, and take it to a computer store so they can find you one with the same physical and electrical characteristics.

Replacing a power supply is a decent beginner level project if you're new to hardware tinkering.
posted by Too-Ticky at 6:45 AM on December 4, 2016

Sometimes there is a software cause. This happened to me when I upgraded from Win7 to Win10.
posted by Obscure Reference at 6:59 AM on December 4, 2016

I agree with the commenters upthread who suggested this could be a power supply problem. But before you open up the case, try easy stuff first.

1) It could be a misbehaving device driver (and the change in behavior could be due to a recent update). Try disconnecting all non-essential peripherals (especially USB stuff). And by "non-essential" I mean everything but monitor, keyboard and mouse. See if sleep/wake works. If so, add stuff back one thing at a time until it stops working.

2) If (1) brings no joy, try resetting your BIOS settings to the conservative / failsafe defaults.
posted by sourcequench at 7:08 AM on December 4, 2016

Can you post a link to a picture of your Acer desktop? What model is it?

If it's one of the ones with the eleven-litre case I'm thinking about, the PSU is physically quite small; there's a lot packed in there, which is probably why it's a bit prone to failure.

Getting those out is a little bit non-obvious. There are three PSU mounting screws at the back of the case; taking those out lets you remove a little cover plate that doesn't seem to be doing much. However, removing it exposes another screw that secures the top panel of the case. Having got the cover plate off, give the top of the case a sharp slap that drags backward on impact, and the top panel will disengage from its mounting slots. Having removed that, there's a screw through the top of the case into a bracket attached to the PSU. Once that's out, you can push the PSU out through the back panel. It's a tight fit, and it will need a bit of wobbling and persistence; in particular, try not to tear the sticky labels too much as they drag through the opening, or they'll pill up and jam it.

But if you work patiently, and make notes (or preferably take photos) of where all the connectors have to get plugged back in before you unplug them, it's pretty much just Lego for grownups.
posted by flabdablet at 11:03 AM on December 4, 2016

making sure all the myriad connectors to various components inside the case

...where "myriad", in this instance, actually means "four": big chunky 24-way block for main motherboard power, small 4-way block tucked awkwardly under the fan shroud for CPU power, one flat black SATA power connector to the hard disk drive, and a flat white Molex connector that goes to a Molex-to-SATA-power adapter for the optical drive.

All those connectors are shaped in such a way that plugging them in wrong requires way more force than plugging them in right.
posted by flabdablet at 11:09 AM on December 4, 2016

Thank you very much for all the great answers! I really appreciate it!

flabdablet: I think you are right - it is a small (narrow, vertical, x1420-es20p) model (I think it looks similar to this one - sorry, I can't post a photo of mine at the moment). The seller said it was a hybrid (my term, not theirs) of a laptop-desktop. (I don't remember the term eleven litre before, but I think your guess is right.) At the time, they said hardware upgrades would be difficult because of the size.

I will look into a new power supply and follow your instructions and try to install one.

Thanks very much everyone.
posted by philfromhavelock at 12:58 PM on December 4, 2016

OK. That's not the same case as the Veriton S460 I gave detailed instructions for, so I don't know what you're going to find as you take it apart. It appears to be quite a lot smaller, so the innards are probably fairly tightly packed in.

Case metalwork is all a bit of a black art and that goes double for small-form-factor PCs, but finding the right combination of screws, hooks, nubbins and slide rails to get the thing to pieces and back again will not be impossible if you just proceed carefully and take good notes.

Looks like the PSU for that model isn't made any more either, but the lovely people at atxpowersupplies.com have adapted something smaller to fit.
posted by flabdablet at 3:28 PM on December 4, 2016

Also looks like their replacement has the more modern 20/24 pin main connector rather than the 20 pin one that will have come with your original PSU.

If your motherboard only has the 20-pin socket, you'll find that the extra four pins in the plug are in a section that can just be slid off as a block. They don't need plugging in anywhere else; just leave them hanging.

The replacement supply also has more wiring and connectors emerging from it than you're going to need. In a tight little case like the one you're working with, you might need to experiment a bit to find a neat place to stow those. Main thing is to understand how the cooling air is supposed to move through the case before you remove the old supply. After fitting the new one, just do your best not to block up anything with fins or vents on it by jamming great clumps of cable right next to it.

You might also find that you need to clip a few nylon zip ties to release the old wiring from the case so you can withdraw the old PSU. For each of those, double-check that no cable has sneaked its way between the jaws of your clippers before applying the fatal squeeze. Yes you're replacing the PSU so cutting the old one's wires wouldn't matter too much, but it's quite common to find that wiring zip-tied to internal USB or audio wiring that you don't want to be repairing if you don't have to.

Personally I never bother with zip ties when I'm putting a new PSU in an old PC, purely because they are such a pain in the arse to remove if that ever has to happen. If I'm going to tidy up internal wiring bundles, I use those little black twist ties that come with every printer cable and network cable you buy.
posted by flabdablet at 3:49 PM on December 4, 2016

This YouTube video guide to replacing the PSU in an Aspire X1200 will probably help with your X1420, which I expect has quite a similar internal layout.
posted by flabdablet at 4:01 PM on December 4, 2016

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