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iMac vs UPS

Message #1 - Posted 2012/01/05 - Jim Gibson

I had a problem setting up a new iMac over Christmas, and thought I would share my experience. The saga may not be ended, yet, but I will save that for a later post.

My goal just before Christmas was to replace my wife's ancient PowerPC Mac Mini with a new Intel system. She had been complaining of "too much color wheel" time, the Activity Monitor indicated all memory was in use, and the Mac Mini had been maxed out at 1GB.

I walked into the local Apple store after work on Dec 22 and walked out with the low-end iMac computer-in-a-box (21.5" screen, 2.5GHz CPU, 4GB memory).

I set the computer up in the living room and transferred files using Migration Assistance and the Time Machine backup on an external Firewire 400/800 drive, which worked great. I ran Software Update over WiFi, and since the computer came with 1.7.0 (Lion), there were about 2-3 GB of updates.

After the updates were done, I moved the computer to my wife's desk, plugged its power cord into a Belkin UPS that had been used for the lifetime of the Mac Mini, plugged in all of the peripherals, which included a data line to the Belkin UPS, and booted up.

The computer started normally, stayed up for 5-10 seconds, and promptly turned itself off. I gulped, wondering if I had gotten a lemon or broken the new computer, I then unplugged all cables (network, USB, speakers) and rebooted while holding down the shift key (safe mode).

The computer came up and stayed up. I breathed a sigh of relief and set about re-installing software from disks, as there were lots of icons in the dock with white circle-slashes over them, indicating they were PowerPC applications that would no longer run.

After doing that for awhile, I rebooted, this time without holding down the shift key. The computer rebooted and stayed up. I then plugged in the network cable and did some downloading and updating of applications.

At that point I thought I was home free, so I plugged in the USB hub into which the Belkin UPS was connected. Immediately, a window containing a message about running on UPS power popped up, and the computer shut down after 5 seconds.

I unplugged the USB hub and turned on the computer, which stayed up this time. I went to System Preferences -> Energy Saver to check out the UPS panel and to tell the computer to ignore status info from the UPS. There wasn't a UPS panel! I plugged the UPS data cable (into the back of the computer this time rather than the USB hub), and the "running on backup power" dialog reappeared, and the computer shut down. During the 5-10 seconds the computer stayed up, I could see that there was now a UPS panel in the Energy Saver panel. However, I didn't have enough time to inspect or change any of the settings.

So there does seem to be a bit of a Catch-22 here if your UPS is misbehaving: Without the UPS data cable attached, you can't change or even see any of the UPS power settings. With the UPS data cable attached, your computer won't stay up.

I immediately went to Fry's and bought a new UPS (APC this time) to replace the Belkin. The computer booted and stayed up, the UPS panel appeared, and I could see and change the UPS settings. The APC UPS came 85% charged, so we were up and running in short time.

The obvious diagnosis is a bad or simply old UPS, but why hadn't it caused a problem for the Mac Mini? I suppose the iMac takes more power and the old UPS just couldn't handle it.

Next up: Why does my new iMac shut itself off after sleeping for two hours, and why do I need to unplug it to restart it? Including a trip to the Genius Bar and a brand, new replacement iMac.

Jim Gibson

Message #2 - Posted 2012/01/05 - Barry Margolin

Previously, Jim Gibson wrote:

So there does seem to be a bit of a Catch-22 here if your UPS is misbehaving: Without the UPS data cable attached, you can't change or even see any of the UPS power settings. With the UPS data cable attached, your computer won't stay up.

You can edit the .plist file directly. It's /Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist, here are the relevant entries:

<key>UPSDefaultThresholds</key>
<dict>
<key>UPSShutdownAfterMinutes</key>
<dict>
<key>Enabled</key>
<false/>
<key>Value</key> <integer>0</integer>
</dict>
<key>UPSShutdownAtLevel</key>
<dict>
<key>Enabled</key>
<true/>
<key>Value</key> <integer>5</integer>
</dict> <key>UPSShutdownAtMinutesLeft</key>
<dict>
<key>Enabled</key>
<true/>
<key>Value</key> <integer>0</integer>
</dict>
</dict>

The obvious diagnosis is a bad or simply old UPS, but why hadn't it caused a problem for the Mac Mini? I suppose the iMac takes more power and the old UPS just couldn't handle it.

Maybe the old machine didn't have the same shutdown settings. I'm not sure if Migration Assistant copies the Energy Saver preferences, since these are often tailored to different types of machines.

Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

Message #3 - Posted 2012/01/06 - JF Mezei

With the older PowerPC machine (I suspect stuck at Tiger ?), did it recognoze the Belkin UPS ?

It is possible that it didn't even consider the presence of a UPS.

With the newer OS-X versions, it recognises the UPS, and perhaps doesn't work properly with that UPS.

There is some application you can have (I forget its name) which runs on OS_X and gives you better control over interaction with the UPS.

here is the scoop of how OS-X deals with the UPS:

When the UPS tells it that it is running on Battery, the OS will shutdown by itself after X minutes, but stop short of a powering down. It then waits for the UPS to cut power. This way, it is treated by the computer's firmware as a power failure and the computer will power back up and boot automatically when the UPS restores power.

Message #4 - Posted 2012/01/06 - *Hemidactylus*

On 01/05/2012 08:30 PM, Jim Gibson wrote:

I had a problem setting up a new iMac over Christmas, and thought I would share my experience. The saga may not be ended, yet, but I will save that for a later post.

My goal just before Christmas was to replace my wife's ancient PowerPC Mac Mini with a new Intel system. She had been complaining of "too much color wheel" time, the Activity Monitor indicated all memory was in use, and the Mac Mini had been maxed out at 1GB.

I walked into the local Apple store after work on Dec 22 and walked out with the low-end iMac computer-in-a-box (21.5" screen, 2.5GHz CPU, 4GB memory).

I set the computer up in the living room and transferred files using Migration Assistance and the Time Machine backup on an external Firewire 400/800 drive, which worked great. I ran Software Update over WiFi, and since the computer came with 1.7.0 (Lion), there were about 2-3 GB of updates.

After the updates were done, I moved the computer to my wife's desk, plugged its power cord into a Belkin UPS that had been used for the lifetime of the Mac Mini, plugged in all of the peripherals, which included a data line to the Belkin UPS, and booted up.

The computer started normally, stayed up for 5-10 seconds, and promptly turned itself off. I gulped, wondering if I had gotten a lemon or broken the new computer, I then unplugged all cables (network, USB, speakers) and rebooted while holding down the shift key (safe mode).

The computer came up and stayed up. I breathed a sigh of relief and set about re-installing software from disks, as there were lots of icons in the dock with white circle-slashes over them, indicating they were PowerPC applications that would no longer run.

After doing that for awhile, I rebooted, this time without holding down the shift key. The computer rebooted and stayed up. I then plugged in the network cable and did some downloading and updating of applications.

At that point I thought I was home free, so I plugged in the USB hub into which the Belkin UPS was connected. Immediately, a window containing a message about running on UPS power popped up, and the computer shut down after 5 seconds.

I unplugged the USB hub and turned on the computer, which stayed up this time. I went to System Preferences -> Energy Saver to check out the UPS panel and to tell the computer to ignore status info from the UPS. There wasn't a UPS panel! I plugged the UPS data cable (into the back of the computer this time rather than the USB hub), and the "running on backup power" dialog reappeared, and the computer shut down. During the 5-10 seconds the computer stayed up, I could see that there was now a UPS panel in the Energy Saver panel. However, I didn't have enough time to inspect or change any of the settings.

So there does seem to be a bit of a Catch-22 here if your UPS is misbehaving: Without the UPS data cable attached, you can't change or even see any of the UPS power settings. With the UPS data cable attached, your computer won't stay up.

I immediately went to Fry's and bought a new UPS (APC this time) to replace the Belkin. The computer booted and stayed up, the UPS panel appeared, and I could see and change the UPS settings. The APC UPS came 85% charged, so we were up and running in short time.

The obvious diagnosis is a bad or simply old UPS, but why hadn't it caused a problem for the Mac Mini? I suppose the iMac takes more power and the old UPS just couldn't handle it.

Next up: Why does my new iMac shut itself off after sleeping for two hours, and why do I need to unplug it to restart it? Including a trip to the Genius Bar and a brand, new replacement iMac.

It could be that the power supply unit (PSU) in your new iMac is really picky about what kinda power it receives. Lower end UPS output a step-wave pattern and newer active PFC PSUs need true sine wave power.

http://www.dougv.com/2010/03/01/active-pfc-enabled-psus-are-not-compatable-with-most-low-end-ups/

I ran into this at work with some newer Dell PCs. They kept spontaneously shutting down. Try plugging oyur iMac into a non-battery backup socket on the box (ie- surge suppress only) and see if the same problem happens. If not, you might have pinpointed the culprit. When the UPS goes to battery backup and puts out a square pattern to your iMac it might get upset and shutdown.

If the iMac still shuts down it's something else.

*Hemidactylus*
-Win or Lose...Tiny Tim is better than Big Ben
*Atheists for Tebow over Roethlisberger*

Message #5 - Posted 2012/01/06 - *Hemidactylus*

On 01/06/2012 12:09 AM, JF Mezei wrote:

With the older PowerPC machine (I suspect stuck at Tiger ?), did it recognoze the Belkin UPS ?

It is possible that it didn't even consider the presence of a UPS.

With the newer OS-X versions, it recognises the UPS, and perhaps doesn't work properly with that UPS.

There is some application you can have (I forget its name) which runs on OS_X and gives you better control over interaction with the UPS.

here is the scoop of how OS-X deals with the UPS:

When the UPS tells it that it is running on Battery, the OS will shutdown by itself after X minutes, but stop short of a powering down. It then waits for the UPS to cut power. This way, it is treated by the computer's firmware as a power failure and the computer will power back up and boot automatically when the UPS restores power.

It could be the iMacs power supply. Newer power supplies have this thing called Active PFC which perhaps doesn't play nice with UPSs that don't output true sine wave when on battery backup. Or if not that it could be something between the PSU of the iMac and the UPS being used (the below links have some back and forth on the issue of Active PFC and sine wave forms):

http://www.howtofixcomputers.com/forums/dell/pure-sine-wave-upses-new-dell-pcs-282853.html

http://forums.macrumors.com/showthread.php?t=1263969&highlight=+pure+sine+wave+

https://discussions.apple.com/thread/2202399?start=0&tstart=0

https://discussions.apple.com/thread/2517026?threadID=2517026&tstart=120

Again, not sure if this is the problem the OP is experiencing, but it's something to think about.

*Hemidactylus*
-Win or Lose...Tiny Tim is better than Big Ben
*Atheists for Tebow over Roethlisberger*

Message #6 - Posted 2012/01/06 - Jim Gibson

Previously, JF Mezei wrote:

With the older PowerPC machine (I suspect stuck at Tiger ?), did it recognoze the Belkin UPS ?

The old machine is running Leopard (10.5.8). It recognized the Belkin just fine. Worked well together for 5+ years.

It is possible that it didn't even consider the presence of a UPS.

Nope. The UPS panel was displayed in the System Preferences Energy Saver panel.

With the newer OS-X versions, it recognises the UPS, and perhaps doesn't work properly with that UPS.

That is a possibility. I lost whatever software disk came with the Belkin a long time ago. I checked the Belkin website and couldn't find anything that wasn't PowerPC specific.

There is some application you can have (I forget its name) which runs on OS_X and gives you better control over interaction with the UPS.

The APC (and probably the Belkin) come with software, mostly for Windows, but maybe also for Mac. I don't use them now, because the UPS monitoring functions have been built into the OS. I am thinking that UPS manufacturers have a standard data interface to make this possible.

here is the scoop of how OS-X deals with the UPS:

When the UPS tells it that it is running on Battery, the OS will shutdown by itself after X minutes, but stop short of a powering down. It then waits for the UPS to cut power. This way, it is treated by the computer's firmware as a power failure and the computer will power back up and boot automatically when the UPS restores power.

There are three settings in the Mac OS X UPS panel:

1. Shutdown After X Minutes
2. Shutdown When UPS Battery Has Reached Y Percent
3. Shutdown When Z Minutes Left

My guess is that whenever one of these conditions becomes true, the computer starts an unconditional shutdown process (that cannot be over-ridden by a stuck application).

Jim Gibson

Message #7 - Posted 2012/01/06 - Jim Gibson

Previously, Barry Margolin wrote:

Previously, Jim Gibson wrote:

So there does seem to be a bit of a Catch-22 here if your UPS is misbehaving: Without the UPS data cable attached, you can't change or even see any of the UPS power settings. With the UPS data cable attached, your computer won't stay up.

You can edit the .plist file directly. It's /Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist, here are the relevant entries:

Thanks. I didn't think of that.

Jim Gibson

Message #8 - Posted 2012/01/06 - Jim Gibson

Previously, *Hemidactylus* <ecphoric@hotmail.com> wrote:

On 01/05/2012 08:30 PM, Jim Gibson wrote:

I had a problem setting up a new iMac over Christmas, and thought I would share my experience. The saga may not be ended, yet, but I will save that for a later post.

It could be that the power supply unit (PSU) in your new iMac is really picky about what kinda power it receives. Lower end UPS output a step-wave pattern and newer active PFC PSUs need true sine wave power.

http://www.dougv.com/2010/03/01/active-pfc-enabled-psus-are-not-compatable-wit h-most-low-end-ups/

I ran into this at work with some newer Dell PCs. They kept spontaneously shutting down. Try plugging oyur iMac into a non-battery backup socket on the box (ie- surge suppress only) and see if the same problem happens. If not, you might have pinpointed the culprit. When the UPS goes to battery backup and puts out a square pattern to your iMac it might get upset and shutdown.

If the iMac still shuts down it's something else.

Thanks, but I don't think so. The iMac would run fine on the battery backup power. It wasn't until I plugged in the UPS data cable that the computer shut itself down.

I have ordered a new battery for the Belkin (only about $20). I can see if the iMac runs off the new battery.

Jim Gibson

Message #9 - Posted 2012/01/06 - Alan Browne

On 2012-01-06 11:39 , *Hemidactylus* wrote:

It could be that the power supply unit (PSU) in your new iMac is really picky about what kinda power it receives. Lower end UPS output a step-wave pattern and newer active PFC PSUs need true sine wave power.

http://www.dougv.com/2010/03/01/active-pfc-enabled-psus-are-not-compatable-with-most-low-end-ups/

I'm too lazy to look, but what does Apple say about square wave inverters?

"We demand rigidly defined areas of doubt and uncertainty." Douglas Adams - (Could have been a GPS engineer).

Message #10 - Posted 2012/01/06 - Barry Margolin

Previously, Jim Gibson wrote:

Previously, JF Mezei wrote:

With the older PowerPC machine (I suspect stuck at Tiger ?), did it recognoze the Belkin UPS ?

The old machine is running Leopard (10.5.8). It recognized the Belkin just fine. Worked well together for 5+ years.

It is possible that it didn't even consider the presence of a UPS.

Nope. The UPS panel was displayed in the System Preferences Energy Saver panel.

With the newer OS-X versions, it recognises the UPS, and perhaps doesn't work properly with that UPS.

That is a possibility. I lost whatever software disk came with the Belkin a long time ago. I checked the Belkin website and couldn't find anything that wasn't PowerPC specific.

There is some application you can have (I forget its name) which runs on OS_X and gives you better control over interaction with the UPS.

The APC (and probably the Belkin) come with software, mostly for Windows, but maybe also for Mac. I don't use them now, because the UPS monitoring functions have been built into the OS. I am thinking that UPS manufacturers have a standard data interface to make this possible.

I had a Belkin UPS several years ago, it used software called "bulldog", I think. It became superfluous once Apple built UPS management directly into the system (I don't remember which release this was).

Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

Message #11 - Posted 2012/01/09 - John Holt

On 2012-01-06 01:30:33 +0000, Jim Gibson said:

I had a problem setting up a new iMac over Christmas, and thought I would share my experience. The saga may not be ended, yet, but I will save that for a later post.

My goal just before Christmas was to replace my wife's ancient PowerPC Mac Mini with a new Intel system. She had been complaining of "too much color wheel" time, the Activity Monitor indicated all memory was in use, and the Mac Mini had been maxed out at 1GB.

I walked into the local Apple store after work on Dec 22 and walked out with the low-end iMac computer-in-a-box (21.5" screen, 2.5GHz CPU, 4GB memory).

I set the computer up in the living room and transferred files using Migration Assistance and the Time Machine backup on an external Firewire 400/800 drive, which worked great. I ran Software Update over WiFi, and since the computer came with 1.7.0 (Lion), there were about 2-3 GB of updates.

After the updates were done, I moved the computer to my wife's desk, plugged its power cord into a Belkin UPS that had been used for the lifetime of the Mac Mini, plugged in all of the peripherals, which included a data line to the Belkin UPS, and booted up.

You did not say that you checked, so perhaps you are short of power. Your iMac will need more Watts than a Mac Mini. I made the mistake of having a UPS that did not provide enough power. After getting a properly sized UPS, all was well.

The computer started normally, stayed up for 5-10 seconds, and promptly turned itself off. I gulped, wondering if I had gotten a lemon or broken the new computer, I then unplugged all cables (network, USB, speakers) and rebooted while holding down the shift key (safe mode).

The computer came up and stayed up. I breathed a sigh of relief and set about re-installing software from disks, as there were lots of icons in the dock with white circle-slashes over them, indicating they were PowerPC applications that would no longer run.

After doing that for awhile, I rebooted, this time without holding down the shift key. The computer rebooted and stayed up. I then plugged in the network cable and did some downloading and updating of applications.

At that point I thought I was home free, so I plugged in the USB hub into which the Belkin UPS was connected. Immediately, a window containing a message about running on UPS power popped up, and the computer shut down after 5 seconds.

I unplugged the USB hub and turned on the computer, which stayed up this time. I went to System Preferences -> Energy Saver to check out the UPS panel and to tell the computer to ignore status info from the UPS. There wasn't a UPS panel! I plugged the UPS data cable (into the back of the computer this time rather than the USB hub), and the "running on backup power" dialog reappeared, and the computer shut down. During the 5-10 seconds the computer stayed up, I could see that there was now a UPS panel in the Energy Saver panel. However, I didn't have enough time to inspect or change any of the settings.

So there does seem to be a bit of a Catch-22 here if your UPS is misbehaving: Without the UPS data cable attached, you can't change or even see any of the UPS power settings. With the UPS data cable attached, your computer won't stay up.

I immediately went to Fry's and bought a new UPS (APC this time) to replace the Belkin. The computer booted and stayed up, the UPS panel appeared, and I could see and change the UPS settings. The APC UPS came 85% charged, so we were up and running in short time.

The obvious diagnosis is a bad or simply old UPS, but why hadn't it caused a problem for the Mac Mini? I suppose the iMac takes more power and the old UPS just couldn't handle it.

Next up: Why does my new iMac shut itself off after sleeping for two hours, and why do I need to unplug it to restart it? Including a trip to the Genius Bar and a brand, new replacement iMac.

John Holt

Message #12 - Posted 2012/01/09 - Jim Gibson

Previously, John Holt wrote:

On 2012-01-06 01:30:33 +0000, Jim Gibson said:

After the updates were done, I moved the computer to my wife's desk, plugged its power cord into a Belkin UPS that had been used for the lifetime of the Mac Mini, plugged in all of the peripherals, which included a data line to the Belkin UPS, and booted up.

You did not say that you checked, so perhaps you are short of power. Your iMac will need more Watts than a Mac Mini. I made the mistake of having a UPS that did not provide enough power. After getting a properly sized UPS, all was well.

How does one check? You would have to know how much power the iMac was drawing and how much the UPS could supply.

The iMac could run just fine while plugged into the UPS. It was only when the data cable from the UPS was plugged into the computer that the computer shut down. Does a UPS provide more power when plugged in than it does when on battery.

Jim Gibson

Message #13 - Posted 2012/01/10 - Tom Harrington

Previously, Jim Gibson wrote:

Previously, John Holt wrote:

On 2012-01-06 01:30:33 +0000, Jim Gibson said:

After the updates were done, I moved the computer to my wife's desk, plugged its power cord into a Belkin UPS that had been used for the lifetime of the Mac Mini, plugged in all of the peripherals, which included a data line to the Belkin UPS, and booted up.

You did not say that you checked, so perhaps you are short of power. Your iMac will need more Watts than a Mac Mini. I made the mistake of having a UPS that did not provide enough power. After getting a properly sized UPS, all was well.

How does one check? You would have to know how much power the iMac was drawing and how much the UPS could supply.

The iMac could run just fine while plugged into the UPS. It was only when the data cable from the UPS was plugged into the computer that the computer shut down. Does a UPS provide more power when plugged in than it does when on battery.

It's because of questions like this that I have a Kill-A-Watt (http://amzn.com/B00009MDBU) for measuring power usage.

Tom "Tom" Harrington
Independent Mac OS X developer since 2002
http://www.atomicbird.com/

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