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powermac g5 memory problems

My trusty Powermac G5 which has not given any problems since I bought it in 2004 is now very unhappy.



It began when wouldn't boot. I took it into an apple service place who immediately announced that it was obsolete and they wouldn't be able to do anything but look at it and run a diagnostic.



They returned it saying it was a faulty memory module and it now ok which it wasn't.



I can now get it up and running for about an hour when it makes a rasping noise and freezes.



Letting it all cool down and moving the memory modules around (I have reduced it down to 2 x I gb modules) and it boots and repeats the cycle - fine for about an hour and then freezes with the rasping type noise.



The fans are all fine and it doesn't appear overly hot inside.



Any thoughts?



Whilst I shall be getting a new apple desktop I very much want to keep the G5 going as it will keep going all sorts of peripherals which I occasionally use.

Posted on Oct 12, 2012 6:08 AM

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Posted on Oct 12, 2012 10:26 AM

Hi Robert, tough to tell, but my guess at this point is that the thermal paste between CPU(s) & heatsink(s) needs replacing.

25 replies

Oct 14, 2012 7:03 PM in response to Robert Albury

Let me give you something to try. The thermal paste has nothing to do with it. Remove the ram from the computer and start the computer up, with no ram in it, and turn it off, you'll probably have to force quit it. Then insert one ram stick in and do a full start up, and turn off. This time you won't have to force quit. Repeat this till you have all the ram sticks back in place. Ram gets corrupted, I've done this on many computers and got them going. It's worth a try. I've seen ram go bad but seldom, usually it's the slot on the motherboard that it fits in, that stops recognizing it.


The symtoms your mentioning though, sounds like a hard drive going bad. When they start to go the computer starts acting erradically and yes freeze up. And it gets that raspy sound. So if you have a spare hard drive and the original OS you could try swapping out a hard drive, if you don't want to give up on this computer that you seem to really like.

Nov 6, 2012 4:01 AM in response to Jacumba

Hi Jacumba,



I haven't been able to pursue this for the last few weeks.


Thanks for your suggestions which I am now trying out, although I don't fully understand the logic of some of them.


The reason memory was thought to be a problem int he first place was that the front led was flashing three time - suggesting a memory fault.


The G5 doesn't start up with zero memory.

Placing the old memory in after re-powering resulted in the first modules not doing anything - the second set I placed in (original pair 256MB) enabled it to startup but not to do anything (I assume not enough memory).


I have followed this with the original pair 256MB plus the pair which wouldn't let it start up just before (pair IGB). It booted and works.


I have done a SMART check on the hard disk which reveals nothing.


I am just leaving it running to see what happens.


Whilst it could well be the hard disk playing up when it went down before the led on the front would always do the three lights flashing and before when I swapped the memory modules around it would work but then freeze.


Anyway all suggestions will be followed as I would like to keep it running if only to maintain OS 10.4 to be able to access a few OS9 programmes and to be able to use the dial up modem.

Nov 6, 2012 5:08 AM in response to Robert Albury

The three flashes of the power LED in a G5 indicate a RAM fault, specifically "No RAM banks passed memory testing" . Although total failure of all RAM at once is likely uncommon, RAM should be tested with Memtest X or Rember to confirm the condition of the RAM. Testing with Memtest X in Single User mode is the surest way to obtain a definitive test result, especially when RAM faults are intermittent.


RAM utilities other than the two mentioned are generally inferior and can only be trusted if fault is found. Most other test utilities are "all or nothing" and rarely find the intermittent faults which are more common than complete failure.


In machines where the RAM tests good, it is a fairly common condition in G5's to have solder connections failing at the memory controller and/or the RAM slots. These failures often cause the three flash report at failure of POST.

These machines (those with degrading solder) have limited life left, as is, and will require replacement of logic board or reflow of solder connections for prolonged, continued use.


One additional issue that RAM faults can cause is data corruption. Data corruption can cause a myriad of issues and the use of Disk Utility or Disk Warrior is required to repair the data corruption before system failure occurs.

Boot to the OS X install disc, select the language to be used, then, in the next window, from the menu bar in Utilities, select Disk Utility. Choose your system drive and run the "Repair Disk" command.


If errors are found and corrected, run the Repair Disk command again.

After the repair attempts are completed, restart normally.


DO test the RAM.......

Nov 6, 2012 8:47 AM in response to Jacumba

Thanks again Jacumba.


The latest - the G% ran happily until lunchtime (2.5 hours) and then I put it to sleep. It did not recover.


Again after unplugginh the memory and repluggi it reserected.


I have just run memtest and it looks bad but I cannot interpret the results.


Any further suggestions gratefully received.


regards,


Robert


Mac OS X 10.4.11 (8S165) running in multiuser mode

Memory Page Size: 4096

System has 2 PPC processors(s) with Altivec

Requested memory: 1386MB (1453981696 bytes)

Available memory: 1386MB (1453981696 bytes)

Allocated memory: 1386MB (1453981696 bytes) at local address 0x0000000004008000

Attempting memory lock... locked successfully

Partitioning memory into 2 comparison buffers...

Buffer A: 693MB (726990848 bytes) starts at local address 0x0000000004008000

Buffer B: 693MB (726990848 bytes) starts at local address 0x000000002f558000

Running 1 test sequence... (CTRL-C to quit)

Test sequence 1 of 1:

Running tests on full 1386MB region...

Stuck Address : testing 1 of 16

FAILURE! Data mismatch at local address 0x0000000044b8e718

Actual Data: 0xffffffffba4718e7

Linear PRN : testing 3 of 16

FAILURE! Data mismatch at local address 0x0000000044b8e718

Expected Data: 0xa268527acb33ab7a, Actual Data: 0xa268527aca33ab7a

Running comparison tests using 693MB buffers...

Random Value :

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0xfffb463e7f757330, BUFB Data: 0xfffb463e7e757330

Compare XOR : ok

Compare SUB : ok

Compare MUL :

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0xe08ca21a936a86e3, BUFB Data: 0xe08ca21a926a86e3

Compare DIV : ok

Compare OR :

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0x1f7fa012a3ffdf8d, BUFB Data: 0x1f7fa012a2ffdf8d

Compare AND :

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0x1f37a01023e91e00, BUFB Data: 0x1f37a01022e91e00

Sequential Increment:

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0xf62ed6c0dd270578, BUFB Data: 0xf62ed6c0dc270578

Solid Bits : testing 2 of 64

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0xffffffffffffffff, BUFB Data: 0xfffffffffeffffff

Block Sequential : testing 2 of 256

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0x0101010101010101, BUFB Data: 0x0101010100010101

Checkerboard : testing 2 of 64

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0x5555555555555555, BUFB Data: 0x5555555554555555

Bit Spread : testing 1 of 128

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0xfffffffffffffffa, BUFB Data: 0xfffffffffefffffa

Bit Flip : testing 2 of 512

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0xfffffffffffffffe, BUFB Data: 0xfffffffffefffffe

Walking Ones : testing 1 of 128

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0xfffffffffffffffe, BUFB Data: 0xfffffffffefffffe

Walking Zeroes : testing 25 of 128

FAILURE! Data mismatch at local BUFA address 0x000000001963e718, BUFB address 0x0000000044b8e718

BUFA Data: 0x0000000001000000, BUFB Data: 0x0000000000000000

*** Address Test Failed *** One or more DIMM address lines are non-functional.

Execution time: 146 seconds.

Nov 7, 2012 6:43 AM in response to japamac

Don't tell me it don't I just worked with a Mac ram 2 weeks ago.The ram may have to be installed in size and matched pairs for a computer. But I'm referring to a repair of corrupted ram, you add them back one stick at a time.

So don't post to me unless you know what your talking about. Just because you read something somewhere doesn't mean it's 100 percent accurate.I have a Mac that doesn't suppose to take a hard drive over 50 GB, well I put a 80 GB in and it worked.

Nov 7, 2012 9:17 AM in response to Jacumba

I do not think that it is the memory modules which are faulty.


After I got the G5 To start again I began to load the memory and tested them with Memtest X.


The first two pairs passed without fault but after I put the G5 to sleep it would not wake up and then when rebooting I get the 3-flashing LED.


The memories that passed all have been considered to be faulty before as they have been in the machine when it has failed.


(I also doubt the suggestion that it is the thermal paste as when it has been working I have been monitoring the CPU temp which seems to be perfectly within its normal range.)


The symptoms are still the same - the machine will not boot - 3-falshing LED. Remove the memory and replug it and the machine boots and then later either will later not wake from sleep or will freeze after a couple of hours. Whilst it is on it appears to work perfectly well with progs like Indesign and Photoshop.

Nov 7, 2012 10:37 AM in response to Robert Albury

I didn't think the ram was bad either, I've seldom seen ram go bad. I've seen the slots on the motherboard that the ram plugs into go bad, that is more common. But from what I've seen when the slot does go bad it doesn't recognize the ram at all for that slot.

Where you mentioned freeze up and rasping sound. Those are symptoms I've seen with a bad hard drive. first the computer will get erradict, then as the hard drive gets worse, you'll get odd sounds from it, something like the rasping sound you mentioned. So I don't want to say go get a hard drive, I'm not 100% sure, but the symptoms are there.

It's absolutely not the thermal paste.

I've notice in the last couple of weeks on craigslist two G 5's showed up for $30, in working condition..Check around and see if you can pick one up for spare parts. If you find the same model it should have identical hardware in it. What model G 5 is this?

Also I don't know if it's been mentioned but have you checked the pram battery on the motherboard? You can get it tested for free at radio shack.

powermac g5 memory problems

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