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4701 Views 5 Replies Latest reply: Apr 14, 2009 10:40 AM by grisou-403
Currently Being ModeratedNov 27, 2006 3:34 AM (in response to grisou-403)Hi grisou403, and a Warm Welcome to Apple Discussions and the Power Mac G5 Forum!
Well, whether it's caused by the firmware update(always a delicate process), 10.4 (OS X seems to get more picky about RAM with each successive update) or by something else - you could try re-seating the RAM, or swapping slots with the RAM that is recognised. Instructions are here
G5 RAM specs. are here
Slot locations are here.
There is a more comprehensive RAM test - Memtest
and User Interface to Memtest - Rember
The precise meaning of "post/0/2048" is probably: "call AppleCare" or "call the place where you bought the RAM" - but try the re-seating, etc. first. Good Luck.
Currently Being ModeratedNov 27, 2006 3:41 AM (in response to grisou-403)grisou403-
Greetings and welcome.
It is possible that the OSX update caused the system to be more selective about the memory that it is using. Each update of OSX seems to cause memory problems. Unless you specifically updated the firmware, none would have been done through the normal course of updating OSX.
Try reseating the RAM. Sometimes that will fix it. If not, did it come with a warranty? Many vendors sell RAM with a lifetime warranty. It is best to avoid those who donnot offer such a warranty.
I don't know of any comprehensive list of POST errors.
-DaddyPaycheckBasement XServe sitting on a Box of Apples, Mac OS X (10.4.8), A collection of clinking, clanking caliginous junk.
Currently Being ModeratedDec 1, 2006 4:53 PM (in response to maclover)To maclover and DaddyPaycheck and all concerned readers
I successfully solved my problem of "disappeared" RAM memory (DDR400) on my PowerMac G5 2x2 GHz ( (July 2004 model with 8 DIMM slots). Mostly with help from two readers - namely MACLOVER and DADDYPAYCHECK who reacted quickly to my call for help, both with a very good advice. And I thank them for that. Because it's really helpful when you're faced with a serious problem never encountered before.
So, being now out of trouble I wrote this "debriefing" note to testify about the process of how to identify and solve the bug.
This could possibly help other "normal" Mac users... I mean non-expert like me.
1 - About the problem's "origin".
I discovered the "missing" RAM just by chance after looking at "About this Mac" and "System Infos" after updating my OSX Tiger system from 10.4.5 to 10.4.7 and 4.8. "About this Mac" mentioned only 1 Go of RAM (instead of 2 Go physically installed 2 years ago). The "System Infos - memory" panel" confirmed that only my four 256 Mo DIMMs were "recognized" and "active" (mentioning type, speed and "state" OK). My two 512 Mo RAM units have "disappeared" and the DIMM slots were identified as "empty"! This diagnosis has been confirmed by "Onyx" and Mac Pilot" utilities. So, it's trustable.
Then I ran the "Apple Hardware Test" software (CD v.2.2.4). The "Quick Test" immediately identified the problem. Its "Hardware Profile" panel showed the 4 x 256 Mo DIMMs as active with correct size/speed. But AHT displayed a "red alert" about the two 512 Mo DIMMs (seated into J41 and J42 slots) that were referred as "0-512 Mo" RAM (instead of straight 512 Mo) with one DIMM (J42) marked as "failed POST". The "Extended Test" provided additional data about the failing RAM with the error message (in red) : "post/0/2048/DIMM5/J42".
2 - No software nor system debugging
First, I suspected the OSX update to have changed something about the RAM's recognition by the System. So, I tried usual maintenance and correcting actions - repairing authorizations, restarting the Mac (even as single user), zapping the PRAM, etc. Then I reinstalled Tiger including a "clean install" from the Tiger DVD. Without any success... Because it has been later demonstrated that intrinsically this kind of "hardware bug" cannot be solved by software "manipulations"!
3 - Solution : Reinstalling the RAM
Thus I decided to turn to the RAM's direct check, as suggested by the two readers.
Initially, I was quite reluctant to put my hands on the memory hard because I never did it. But I found it rather easy to do. After reading the Apple knowledge base's memory replacement guideline ... and taking special care of static electricity (wearing a wire bracelet connected to the G5's case). This point is important as static electricity could definitely damage RAM memory cards.
So I removed the two 512 Mo DIMMs from their original slots and re-installed them into the adjacent pair of slots (in place of two 256 Mo DIMMs).
At the first restart under Tiger 10.4.8.. Bingo : "About this Mac" and "System Infos" panels displayed the expected "2 Go" of RAM. Both the RAM memory cards and the DIMMs slots are OK.
4 - The "Lessons" learned from this troubleshooting.
In conclusion, I would say that above-mentioned readers were right : in such case - "no show" RAM - the best option is to remove and inspect the DIMM and then - if cards and connectors looks good - to reinstall it correctly ... and carefully!
By the way, I would recommend to re-install the suspected DiMMs into a different pair of slots than the original ones. This "cross install" procedure allows to check the validity of both the RAM itself and the DIMM slots with only one manipulation. So there is no need to make another move for installing the RAM by size hierarchy. In my G5 bipro, RAM is now fitted (by pairs) in the DIMMs' rows 1 to 3 with a 256-512-256 Mo sequence and it works.
I would also strongly recommend to run the "Apple Hardware Test" (AHT) software to get a more detailed diagnosis. For example, AHT gave me the error message :"post/O/2048/DIMM5/J42".
While being unable to find a list of POST error codes, I can now try to "reasonably explain" this kind of error message I got. The "Power-on Self Test" (POST) item "0/2048" obviously refer to the RAM size : total "installed" RAM was 2048 Mo (2 Go). But the "0" prefix means that zero Mo were "recognized" (or "active") from some DIMM card(s). Then the "DIMM5/J42" item pointed out to the fifth DIMM (J42) that, in my case, was the "single failure point". But, of course, as RAM is working by pairs on the PowerMac G5 bipro. if just one DIMM "failed" the associated DIMM is also "neutralized" - even if it does not "failed".
Finally, this RAM trouble makes me more comfortable to do still "simple' - but sensitive - maintenance and repair inside my Mac... while being 65 with no special skill in computer's knowledge. So I would say everybody else can succeed too.
Again, many thanks to MacLover and DaddyPaycheck for quick help ...
and Christmas Greetings to all Apple Discussion readers.
Power Mac G5 biprocessors 2 x 2 GHz (July 2004) Mac OS X (10.4.8)
Currently Being ModeratedDec 1, 2006 5:23 PM (in response to grisou-403)Hi grisou-403 - Thank you for the detailed feedback. It's very helpful to know what happened, what you did, what worked, what didn't - especially from someone who is obviously careful and methodical in their problem-solving.
Glad it's fixed - Thanks for taking the time to post such a comprehensive analysis. Good Luck! And Merry Christmas!
Currently Being ModeratedApr 14, 2009 10:40 AM (in response to grisou-403)The unique solution to both problems - wrong Date & Time and Internet connection - is to change the PRAM memory battery of the PowerMac.
It cost me 10 € plus delivery and takes only 5 min. to change it. It's very easy on the PowerMac G5.