[Veltliner]

That's the second time the power went away (which proves, that we don't need Enron to produce a power-out in California).

Of course, my computer was on both times.

Click - and black.

And it didn't respond for a while. I disconnected all the cables. After a while, the iMac started up regularly in both cases,

How bad is that for a computer to lose power in mid-run? Is it bad at all? Do you need to disconnect the cables for a reset afterwards?

[boy8cookie]

You'll lose any unsaved work, and whatever was in memory. It can also mess with your PRAM which effects date & time settings, display settings (brightness, etc). If you don't have surge protection it's possible for a power surge to ruin your power supply. Invest in a UPS and eliminate the worry.

[Veltliner]

I have one of these surge protectors (is that what you call a UPS?).

I just wondered why I had to wait ten minutes before powering on again.

[boy8cookie]

I use the term "UPS" loosely, I was referring to a battery back up with surge protection. So when the power goes out you have time to properly save your files and shut down your machine. As far as waiting 10 minutes... I'm not sure on your electrical situation, are you in control of your fuses etc? It's possible the surge blew a fuse and someone else turned it back on, if you share a living space that is.

[dowNNshift]

Sudden drops with power are always bad to high end electronics. Do you have your Mac connected to a battery back up, aka UPS? A surge strip alone does nothing to protect your Mac from having the rug pulled out from under it.

Connect your Mac to a known good grounded power outlet.
If the machine fails to power on, you may need to reset is Power Manager. You can find detailed instructions on Apple's knowledge base for your exact model. What that will do is reset the circuitry on the Logic Board that controls power up.

After that, as previously suggested, I would reset the Parameter RAM -- you can do this by booting and holding Command + Option + P + R keys simultaneously. Do this until you hear a total of 3 boot chimes and then let go.

If you get a flashing folder or a hang up during the boot process, you may have directory damage. You'll need to boot into safe mode or from the restore disk to repair permissions and force a directory check.

Always have your Mac connected to a quality battery backup. This will protect it from under/over voltage, loss of phase, and sudden outages. APC and Belkin are good brands, although personally and professionally I prefer APC. Depending on your model a 350 or 500 rated model will work best, averaging in price from $45 to $60 dollars at the big box stores.

[ghporter]

Have a good-quality UPS (I use APC's units) and set things up (In Energy Saver) to shut the computer down when it's been on the UPS for a few minutes. After power comes back, wait several minutes before turning things back on. Why? Are you sure power is going to STAY on? That's what I thought... A 500VA UPS should handle any iMac or Mini for lots of time so don't bother going bigger unless you have other stuff you need to power at the same time. Or better yet, get a separate UPS for that stuff-I I have a 350VA unit powering my network hardware (router, wireless, modem, network drive...).

[TomR]

Agreed on getting a APC backup. Mine has saved me numerous times in the past 3 years! I got the 500 model as our power very rarely goes out for more than a few seconds to several minutes any more. I only plug the PC and router into it so it'll last longer power wise. It's rated at 18 minutes if you have your monitor plugged in as well. Don't sweat the sudden power outage, it happens and as saw you're fine. It's surges that could cause more troubles.

[Cold Warrior]

I've seen a couple desktop Macs not start up after a power failure. I've had to open their case and press the PMU reset button. The Macs were old models anyway, and I don't know if the non-booting was caused by the sudden outage or simply a correlation without causation.

[Veltliner]

Originally Posted by boy8cookie 

I use the term "UPS" loosely, I was referring to a battery back up with surge protection. So when the power goes out you have time to properly save your files and shut down your machine. As far as waiting 10 minutes... I'm not sure on your electrical situation, are you in control of your fuses etc? It's possible the surge blew a fuse and someone else turned it back on, if you share a living space that is.

A battery pack! I haven't got that one. I'll look out for one.

Regarding the ten minutes: everything came on right away, just my iMac pouted, before he (I think I have a male iMac) came on again.

[Veltliner]

Originally Posted by dowNNshift 

Sudden drops with power are always bad to high end electronics. Do you have your Mac connected to a battery back up, aka UPS? A surge strip alone does nothing to protect your Mac from having the rug pulled out from under it.

I would reset the Parameter RAM -- you can do this by booting and holding Command + Option + P + R keys simultaneously. Do this until you hear a total of 3 boot chimes and then let go.

If you get a flashing folder or a hang up during the boot process, you may have directory damage. You'll need to boot into safe mode or from the restore disk to repair permissions and force a directory check.

Always have your Mac connected to a quality battery backup. This will protect it from under/over voltage, loss of phase, and sudden outages. APC and Belkin are good brands, although personally and professionally I prefer APC. Depending on your model a 350 or 500 rated model will work best, averaging in price from $45 to $60 dollars at the big box stores.

So far I have not noticed any trouble, but I'll reset the parameter RAM.

What's a 350 or 500 rated model? Does it refer to the amount of energy it can store?

[Veltliner]

Originally Posted by ghporter 

Have a good-quality UPS (I use APC's units) and set things up (In Energy Saver) to shut the computer down when it's been on the UPS for a few minutes. After power comes back, wait several minutes before turning things back on. Why? Are you sure power is going to STAY on? That's what I thought... A 500VA UPS should handle any iMac or Mini for lots of time so don't bother going bigger unless you have other stuff you need to power at the same time. Or better yet, get a separate UPS for that stuff-I I have a 350VA unit powering my network hardware (router, wireless, modem, network drive...).

APC. Thanks for the brand tip.

[JKT]

Fwiw, depending on the type of Mac you have, if the power was off for more than 5 mins it will have reset the power management for you anyway as this is how you do it on the later model e.g. iMacs (pull the cord and leave for 5 mins+).