Canadian Mac Forums at ehMac banner
1 - 9 of 9 Posts

·
Registered
Joined
·
44 Posts
Discussion Starter · #1 ·
Hi Folks,
I've had a 20" iMac running OS 10.4.10 with a 1GB of factory-installed RAM (2 x 512) for a couple of months. It was working flawlessly until yesterday when it suddenly froze without warning - no mouse or keyboard response. I shut it down with the power button and started it up without peripherals and again, it repeatedly froze or the screen went black and it rebooted - sometimes without even reaching the desktop.
I managed to run the hardware test for a minute or so before it froze up, and got an error:
4 MEM/1/40000000: OAA E 232C (might also be Z32C at the end)
This evening, I had a look at the memory to make sure it was properly seated and swapped the cards around to see if it made a difference. Anyway, I'm not getting repeated freeze-ups like yesterday but I've had two kernal panics (the scrolling white text on black background kind ("debugger panic" etc.) and the multilingual grey curtain of death kind) which I've never experienced on this machine before.
I ran an extended hardware test tonight as well as verifying the disk permissions and found nothing wrong.
Anyone have any thoughts as to what the problem may be?
Thanks in advance,
I Jones
 

·
Registered
Joined
·
172 Posts
Try running it with only one stick of ram at a time.
 

·
Registered
Joined
·
44 Posts
Discussion Starter · #3 ·
Try running it with only one stick of ram at a time.
Thanks for the suggestion Mad Mac - I'll try it. I'm curious though, is it the error code that makes you think it's a RAM issue?
I also noticed after I posted my issue, that the kernel panics seemed to mostly occur while looking at music videos in iTunes or in Front Row...
I'm wondering if it's the video card...
 

·
Registered
Joined
·
172 Posts
Bad ram is just the most common problem. I've not seen your code before, a google search may turn up some info on it. If it keeps acting up you'll have to take it in for service. If it is the ram I'de take it in anyway since apple should replace it for you.
 

·
Registered
Joined
·
2 Posts
Problem might be your UPS

My new Intel iMac worked for 3-4 months just fine and then started exhibiting symptoms just as you describe. I finally traced the problem to the (new) UPS I purchased along with the iMac. I have an APC Back-UPS BE550R. I discussed the problem with APC tech support and they researched the issue and determined that the new Intel iMacs probably need the Smart UPS series because Intel Macs require a transfer time of 4-5 milliseconds but the Back-UPS series has transfer rates of 8-10 milliseconds. Be advised that the Smart UPS series is quite a lot more expensive than the Back-UPS series.

For the record, he said that my 2.8 GHz 24" Intel iMac has a maximum wattage rating of 280W and he concludes that I need a UPS having at least 350W capacity due to start-up surges. I calculated that my iMac would run for 9.5 minutes on the recommended smart UPS SUA750 ($320) in the event of a power outage. I haven't purchased a new UPS yet as I'm hoping to get feedback from others whether or not this makes sense.

Meanwhile, my Intel iMac has been plugged into the wall socket for a month now and I haven't experienced any further problems. :)
 

·
Registered
Joined
·
3 Posts
My new Intel iMac worked for 3-4 months just fine and then started exhibiting symptoms just as you describe. I finally traced the problem to the (new) UPS I purchased along with the iMac. I have an APC Back-UPS BE550R. I discussed the problem with APC tech support and they researched the issue and determined that the new Intel iMacs probably need the Smart UPS series because Intel Macs require a transfer time of 4-5 milliseconds but the Back-UPS series has transfer rates of 8-10 milliseconds. Be advised that the Smart UPS series is quite a lot more expensive than the Back-UPS series.

For the record, he said that my 2.8 GHz 24" Intel iMac has a maximum wattage rating of 280W and he concludes that I need a UPS having at least 350W capacity due to start-up surges. I calculated that my iMac would run for 9.5 minutes on the recommended smart UPS SUA750 ($320) in the event of a power outage. I haven't purchased a new UPS yet as I'm hoping to get feedback from others whether or not this makes sense.

Meanwhile, my Intel iMac has been plugged into the wall socket for a month now and I haven't experienced any further problems. :)
I stumbled upon your original thread at <http://forums.macworld.com/message/643752> while researching UPS requirements for my new 24" iMac. I had just purchased the APC BE550G, and was rather upset to read what the APC tech had told you. Based on that "advice," I "upgraded" the BE550G to the BE750G, hoping that the tech's assessment may have been correct regarding the power requirements, but incorrect regarding the transfer-time requirements.

My experience so far with the 750 has not been entirely satisfactory: When the iMac is shut down for the night, the UPS begins to make a “clicking” sound every 10-15 seconds (as if it were switching on and off). The sound continues to repeat itself until I turn on the iMac.

I’m a bit concerned that this may be part of the transfer-time issue that the APC tech had mentioned. However, it happens only when the iMac is turned off (but the UPS still is plugged in and receiving utility power), which seems contrary to the condition described by the APC tech. (In other words, the UPS is not being told “Hey, we’ve lost utility voltage, and the iMac is ‘on’ and needs power.”) Moreover, the previous unit (BE550G) didn’t exhibit this behavior (it was always quiet). So it may instead be a defective unit.

FWIW, I initiated a thread about this in the Apple Discussions Forum (see<http://discussions.apple.com/thread.jspa?threadID=1577204>). So far, the responses I've received seem to reflect the belief that the APC tech is "full of crap." However, these responses seem based less on specific knowledge and more on anecdotal experience that may or may not be applicable.

Although the APC tech indicated to you that "...we now recommend a Smart-UPS for all Macs. Our UPS configurator is being updated to reflect this recommendation," the APC website has still not been changed.

Have you any further information?
 

·
Registered
Joined
·
2 Posts
Not much further information

I waited until this week to see if other people on several forums would provide some knowledgeable information, but nothing much developed. I noticed that APC's web site has been updated to at least include Intel iMacs, but as you said they don't recommend the more expensive smart UPS's but rather the Back-UPS series.

So I emailed their tech support once again and received the reply to go with the smart UPS rather than what their web site says. In fact, they said that either the SUA 1000 or SUA 1500 would be safer than their original recommendation of SUA 750. Those two are way too expensive to use on an iMac so I ordered the SUA 750 yesterday but haven't received it yet.

I have never had the problem with the UPS you mention when the iMac is off, but I rarely turn it off.
 

·
Registered
Joined
·
3 Posts
I waited until this week to see if other people on several forums would provide some knowledgeable information, but nothing much developed. I noticed that APC's web site has been updated to at least include Intel iMacs, but as you said they don't recommend the more expensive smart UPS's but rather the Back-UPS series.
Hmmm...I don't see any change to the configurator. It still refers only to G3, G4, and G5 iMacs only.

So I emailed their tech support once again and received the reply to go with the smart UPS rather than what their web site says.
The folks responding to my Apple Discussions thread have been rather vocal in their opinions that the APC tech is absolutely wrong.

In fact, they said that either the SUA 1000 or SUA 1500 would be safer than their original recommendation of SUA 750. Those two are way too expensive to use on an iMac so I ordered the SUA 750 yesterday but haven't received it yet.
Spending $320 for a UPS to keep an $1,800 machine online for a few minutes during an occasional power outage is a bit too rich for my blood. Perhaps I’d feel differently if I lived in an area where power outages/brownouts/fluctuations were more of a problem. (One of the folks who posted to the Apple Discussions thread pointed me to a site (<http://www.excessups.com/>) that offers lower-cost, refurbished APC UPSs. But I’m not enthusiastic about used electronic equipment from strangers.) But even if I lived in the middle of the Florida Keys, I doubt that I’d ever consider the SUA 1000 or 1500—not for a single iMac!

For the kind of money we’re talking about, I think one might be better off buying a couple of extra backup drives and a bunch of surge protectors, and putting the extra money in a mutual fund towards one's next Mac! (I’ve lived with APC surge protectors and backup drives for years, and haven’t lost much data due to crashes...much less power outages.)

I have never had the problem with the UPS you mention when the iMac is off, but I rarely turn it off.
Well, I’m awaiting a response from the APC tech folks regarding their diagnosis.
 
1 - 9 of 9 Posts
Top