PowerMac G5 startup failures, red LED behind processor

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Level 1

1 points

PowerMac G5 startup failures, red LED behind processor

I have a PowerMac G5 dual 2.5GHz machine, which was put into service in December 2004 and has basically been running non-stop since, with the occasional break for an upgrade or to fix a problem (I have a small marketing consulting business and this is my primary work machine). Recently, after installing a routine upgrade to Safari, the machine started refusing to restart. It started after the Safari upgrade; the upgrade finished, I told it to restart and I left the room. I came back to roaring fans and nothing on the monitor. So, I powered it off and waited a couple of minutes. When I tried to power it back on, I got the boot chime, a little fan noise and then silence. There was a red LED, which appeared to be behind the processors, on. The white LED was also on. But clearly the startup was going no further. So I turned it off, unplugged it for 10 minutes (which is supposed to be how you reset the SMU on this machine), and then it started up.

But that wasn't the end of it...the next time I tried to restart the machine, it again refused, and again gave me the mysterious red LED behind the processors. After a couple of tries of unplugging things and cold starting it, it did finally come back up. I'd had problems with the original hard drive on this machine (it failed and was replaced after 2 years), so I ran diagnostics on the startup drive--no problems. Then I figured I'd zap PRAM. So I shut it down, and tried to zap PRAM on startup...but it wouldn't start this time, so I couldn't zap PRAM. Then I tried unplugging the machine, waiting a while, and starting up again--no go. And I couldn't get it to boot from a backup copy of the system on an outboard firewire drive either. After unplugging everything, including the outboard firewire drives and all the USB devices except the mouse and keyboard, I STILL couldn't get it to come back up. Every time, the furthest it would get would be a grey screen with the apple on it, and that mysterious red LED deep in the bowels of the machine.

Finally, in despair, I brought it to the nearest Apple store and had a Genius look at it. After reproducing the problem (and finding NOTHING in the service manual about that mysterious red LED), he got the machine to boot from an outboard firewire drive running Leopard. He ran the disk utility and confirmed that my startup drive was just fine. He then reinstalled Tiger on my drive, and successfully restarted the machine. He then applied the Tiger combo update and--NO RESTART and no cold STARTUP (and that same red LED inside every time it failed). They couldn't zap PRAM. They even replaced the PRAM battery, but that didn't do anything either.

At that point, I left the machine with them so they could run Apple Diagnostics on the machine and see if there was a hardware problem. I was sure they'd find it was a processor gone up in smoke or something.

The good news is that there is a happy ending to this story. After running diagnostics and confirming that the hardware was just fine, they tried to zap PRAM. It didn't work; the machine wouldn't start. Then they reset the SMU, using the button on the logic board below the lower memory slots (apparently this button is on both the late 2004 and late 2005 PowerMac G5 models, which is not what the documentation says), then zapped PRAM as it was coming up, and lo and behold, the machine started! They then started and restarted it, and all was normal! I can confirm that the machine is now working properly--it starts, it restarts and it is working normally. The guys over at the Apple store were very patient, and this at the height of the holiday shopping season! However, they never did figure out what that mysterious red LED in back of the processors was, though one gentleman opined that it was probably just a light that indicated that it was stuck (well, we KNEW that!).

I still don't know what started this set of problems--clearly something got corrupted somewhere, or possibly multiple somewheres--but the combination of reinstalling the OS and resetting both the SMU (using the button) and PRAM seem to have cured it. I'm posting this in here, not as a question, but so that if anyone else runs into a similar situation, they have some things to try before throwing up their hands in despair. My next question? Why do these things always seem to happen when you're in the middle of some huge project 🙂 ???

PowerMac G5 dual 2.5GHz, late 2004, Mac OS X (10.4.11), 5.5GB RAM

Posted on Dec 23, 2008 11:45 AM

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Answer 1

Lewis

Level 3

650 points

Dec 23, 2008 3:00 PM in response to samarkham

I have about the same machine but it is a 2 mh dual.
Maybe for the third time when coming out of sleep, the screen will be a mosaic of small rectangles with unreadable patchy text here and there if you mouse over the area. It just occurred when I plugged in my ipod.
Well the only way out that I could see was to hold down power key. Then the computer would not boot. It made the chime but no disk activity that I could here and soon the fans started revving up.
I repeated the power down and tried the option key to enter firmware OS choice. Same response. I tried to use the G5 as a target drive. Same response.
Opened it up to look for loose ram or other. Video board which is my only PCI device was firmly seated as were the ram chips. Still same results.
So came here and saw this post. Went looking for an SMU reset button and could find one. Turned the computer on and there was a red LED near the ram chips - ? is this normal. The fan to the drives was going strong but the computer was booting. Once booted, the fan to the drives stopped and indexing for Spotlight commenced as if it were a new drive.
Anyway, it this the above red light? Where exactly would a reset button be if there was one? And do I need a new battery - didn't even know there was one - (I have replaced the one in my G4 several times and usually here the time is always wrong which has not occurred with the G5.
Thanks for any thoughts about this.
Lewis

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Answer 2

samarkham Author

Level 1

1 points

Dec 23, 2008 6:33 PM in response to Lewis

Well, I spoke too soon about all being well...I just found that in all the to-ing and fro-ing and reinstalling we'd done that iTunes wasn't functioning (I needed to plug in my iPhone!). iTunes said it needed a newer version of Quicktime and refused to open. So I did the update, then tried to restart---and it refused to start, SAME AS BEFORE! Aaaaargh! After resetting the SMU, zapping PRAM, and failing to come back up on either the primary system drive or the system installed on one of my firewire drives, I manually opened the optical drive door, inserted the Tiger install CD, reset the SMU several more times, unplugged EVERYTHING attached to the machine, except the keyboard, mouse and monitor, and FINALLY got it to start up (though oddly, it came up with the wrong date/time...but we REPLACED the PRAM battery before...). I'm now installing Tiger on yet another drive in the hope that there really is a software problem causing this mess! (And in the mean time, I'm posting this from my laptop -- a Windows (gasp!) XP machine!) I've got another appointment with the Apple store in the morning...I really hope it's not the processors, 'cause replacing them both will NOT be cheap.

Anyway, the SMU reset button is below the bank of RAM cards, under the lowest one, at the bottom of the machine, in the middle of that area of the board. There's a picture in this article and it looks just like mine. It's a tiny button, and the documentation says it's only in the late 2005 G5s, but I've got a late 2004 G5, and its definitely there. See http://support.apple.com/kb/HT1436

The red LED I'm seeing when this machine doesn't start is only visible through the grating in the front of the machine and appears to be on the board, down behind the processors, if you look closely inside the machine. There are also red LEDs that come on when you forget to put the fan back in the bay, but those are on the left-hand edge of the area where the RAM chips go (at the front of the machine) and it's pretty obvious why they're on 🙂. The PRAM battery, which may need replacing in your case, is on the upper part of the board in the middle, just under the back of the optical drive bay. It looks like what it is...and it's pretty easy to replace if you need to. I may have a bad one myself, since the date/time came up wrong after this last mess of restarts.

I wish you luck with your machine...I've not seen quite that symptom over the years, but you never know. I've certainly seen lots of stuff fail in lots of odd ways (I've had a Mac of one sort or another since 1987 -- back then, when something was unhappy, you got a cherry bomb in the middle of the screen!), though it's usually not so difficult to diagnose the root cause of the problems as it's been lately!

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Answer 3

Lewis

Level 3

650 points

Dec 24, 2008 7:39 AM in response to samarkham

Thanks for the info. I had found the kb article but had trouble with the size of the picture. I assume mine has a reset button and one needs to remove the fans to get to it as I can't appreciate it under the ram trays.
As best I can tell, it was made between Apr and Oct of 2005.It may or not be special as it is from the array of computers that VPI used for their supercomputer before they went to servers for this.
I guess my LED is not the same as yours. It is at the front just above the power on button.
My episodes have been triggered, at least twice, by plugging in an ipod to a sleeping machine. I have used a powered usb port and the one on the front of the machine.
Good luck. Let "us" know how it turns out.

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Answer 4

Dec 25, 2008 7:43 PM in response to samarkham

Oh my god ... I cant believe i read this ..... my computer the same exact thing ... i have tried everything just like you have described ... yet that **** little red light behind the processors ...... i too feel like they are gonna tell me that my processors are gone ..... I have an appointment this week with apple .... man I wish it would have worked out for you .... it would have givin me hope........ swear to god reading your story was like i was explaining it ....... hope we can find some help...... only one other thing that is kinda strange .... i used my computer night and day for 2 years and just now (because of troubleshooting this problem ) found out my memory is configured wrong ... my first 512 bank was never paired with another so 7 of the 8 slots were filled .... but it worked fine all this time .... i am now only trying with 6 slots full as apple says it has to be .... but is that weird or maybe did that weird configuration cause all this **** im going thru now...???/

let me know how it works out for you and i will do the same''\

peace and Merry Christmas

rjk

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Answer 5

samarkham Author

Level 1

1 points

Dec 26, 2008 3:09 PM in response to DOYAWANNA

Well, I have a verdict and it's not good...the problem is on the logic board itself. They stripped everything out of the machine, then put it back into its original configuration, taking out all the extra RAM I had put in and leaving the original 512MB of RAM (which came as 2 256MB DIMMS--I'm not sure why one of these machines would come with a single 512MB DIMM, but if it had been like that for a long time, that doesn't explain why the machine would go wonky now), the video card and one hard drive (though it's not the original--that one died after two years in service). They then ran diagnostics again, which turned up a problem on the logic board (I guess they didn't see this the first time they ran diagnostics?). They think one of the processors may have a problem too, so I'm pretty much hosed. Replacing the logic board and both processors on this particular machine is not much less costly than buying a new machine...sigh.

Anyway, the problem is still intermittent, so mucking about with it will, eventually, get it to start back up, at least right now, but the opinion of the Apple tech is that it's only going to get worse over time. I can probably limp along (turning off sleep mode and avoiding restarts like the plague, and biting my fingernails every time I have to shut it down for any reason) for a little while. But I'm running a small marketing consulting business on this box, and I need a RELIABLE machine, so I guess I'm going to have to cough up for a new Mac Pro. I'm a firm believer in recycling, so maybe I can sell this one for parts to someone who refurbishes them (though I haven't even looked into that, and I have no idea if anyone does that in my area anyway).

I must say I'm disappointed, especially after thinking it was OK after bringing it in the first time. Yes, I've had this machine on constantly for 4 years straight, and that's a lot to ask of a machine (heaven knows my Windows boxes haven't lasted all that well over the years) but this is the first Mac I've had in 20 years of owning Macs that didn't last well past the point where I simply needed a bigger, faster box in order to run my apps properly. I expected at least 2 more years out of this one. Heck, I've got an 11-year-old beige G3 sitting under my desk that's STILL in service. It's being used as a "server" for a couple of SCSI devices (a slide scanner and a dye sublimation printer) that I couldn't easily hook to the G5, so it doesn't do a lot any more, but it is still ticking!

Anyway, I hope everyone else with similar problems has better luck than I'm having!

Happy holidays and best wishes for 2009!

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Answer 6

Jan 4, 2009 3:28 PM in response to samarkham

You all have done a good job in investigation.

I would like to add that my G5 went the same way. Although I turned mine off each night, apparently if the board or some part of the of the power supply wants to go out, the same problem will result over time.

Rather than buy a used logic board, because of cost and may or may not be the real answer, I bought a used, and supposedly guaranteed, faster G5 for nearly the same price. So far, it's working fine. I'll keep the old one for backup(?).

To me, this does not answer the question about the G5 product failure but considering the product is no longer supported, we have no choice but the "used" market.

I really mean that Apple technicians should tell us what the problem is, how to circumvent it, and where to purchase parts.

i was hoping for answers but!!!!

Bud

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Answer 7

thepagod

Level 1

0 points

Jan 23, 2009 1:01 PM in response to samarkham

Hi,

it's kind of weird that everyone seems to be having the same kind of problem at the same time! I have a similar problem, although I haven't been able to see the red LED -- apart from the one that lights up when opening the Mac while it's on.

I have a Dual G5 2.4GHz, bought in August 2005 I think, and it's running Tiger 10.4.11. It's never had any problem with power, and in the past few months it's basically never been completely off, I just restarted it when updates required it -- otherwise it's mostly sleeping during the day and night, and I use it every evening.

A few days ago, it had gone to sleep after I had used it early in the evening. Then I tried to wake it up the usual way -- by moving the cordless Logitech mouse. It didn't work, so I tried hitting a key on the cordless Logitech keyboard, not better. Actually, something was happening: the green LED was blinking on the Logitech base for the mouse and keyboard, but the computer didn't seem to be reacting at all.
Worse: I tried to shut it off by pressing the power button for several seconds (20!!..), nothing happened... Not much of a choice, I had to turn it off by pulling the plug.... And then, after I had put the plug back in, nothing! It simply wouldn't start... I didn't know about the SMU at that time, so I didn't try to reset it, I just unplugged and plugged it back in several times, no change. In the end, I left it plugged in, and then a few minutes later, it came back all on its own!! Weird...

Then it went alright for 2-3 days, and today again it refused to wake up from sleep -- same blinking LED on the logitech base, and still no reaction when using the power button. Then when I pulled the computer to open it, somehow the network cable got unplugged, and that woke the whole computer up... OK, so I thought now I know a way, used the computer, then let it get back to sleep, then again went back to it.... Again, no reaction, and this time even by unplugging the network cable or the USB cable of the logitech base, nothing woke it up. Again I had to pull the power plug. This time I tried to reset the SMU (first with the cable unplugged, then plugged in), but apparently it hasn't had any effect, and the computer still doesn't feel like starting up...

So what should I do? I'm still hoping it's gonna do like last time and finally come back to life, but it's definitely not looking good. I haven't run any diagnostic program yet, and I'm definitely going to do that when it restarts -- if it does!..

I'm lucky to have my Mini and my Macbook to survive, but I also need my G5! :-|

Thx for your help!

David

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Answer 8

Stewbee

Level 1

0 points

Jan 23, 2009 9:41 PM in response to samarkham

I read your thread because my G5 has stopped booting past the Apple symbol, and I was intrigued by one of your remedies (the little SMU button) and I discovered that the led light you were having a problem with lights when the clear plastic shield (I think its called the cooling shield) is not in place. When I put it back the led extinguishes. So you probably had a problem with the sensor that detects whether the cooling sheild was in place!

There are so many threads out there with failing G5s from 2004 & 2005 all doing similar things. Clearly they are all headed this way, and this is a common issue for all G5s which will all stop booting eventually. This is the first mac for me that crapped out, let alone after less than 4 years. I still have my G4 that preceeded my G5 and it still works fine, I had an si that lasted 10 years I think before I sold it.

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Answer 9

OJSosa

Level 1

0 points

Jan 28, 2009 12:08 PM in response to samarkham

Hi All-

I can't believe that I'm having exactly the same problem! My computer is shutting down, locking, or not powering up correctly quite frequently now. It started in October of 2008 (about 3 years to the day from when I got it). The first failure happened just as a lock up (no mouse or keyboard control) while running iTunes on the computer (Entourage and Safari in background not active). After over 30 mins of waiting for it to recover, I simply rebooted the machine with a hard shutdown.

A few days later, it would not come up (awake) out of sleep mode. Several attempts to power-up did not work.

I took the computer to a Apple store in Miami and I had to leave the machine for several days after the Genius Bar support could not figure out what was going on.

I was subsequently called and told that I simply had a RAM sitting loosely and that the machine was now working. I found that hard to believe because the computer was never moved once I got it... and it was kept clean.

Regardless, when I showed up to pick it up, I was able to power it up and it was working just fine.

I immediately upgraded to Leopard OS and added a back-up hard drive to use with Time Machine.

Since the New Year, I've had the problem repeat several times. Running the Apple HW Test tool that comes with the original installation CD does NOT find any issues with ANY of the HW.

I've seen several blogs on MACWORLD.com that suggests that this (these symptoms) are happening a lot in the MAC G5's 3years old. Multiple different proposed solutions (RAM, HD, Logic Board, etc.) have been suggested but no sure-fire fix.

Now I find this thread.

Some details about my system I got from Apple Test Tool:
-
- 2x Power PC, G5 @ 2.7GHz
- 512K L2 (1:1) Cache
- MLB# J5520 **
- Boot ROM 5.2.4f1
- System # G8533 *
- 8GB of DDR SDRAM

... all of which passed Test Tool extended profile.

HOW MUCH MORE FRUSTRATING COULD THIS BE? I think it's some SW update. I would like to got back to bare-boned OS X and NOT run any applications that Apple auto-updates (like iTunes)... and give that a try.

This system is too pricy to be "flipping" every 3 years.

Please, if anyone here has a fix... detail it to me.

Thanks for keeping us all updated. We're not alone!

Message was edited by: OJSosa

Message was edited by: OJSosa

<Edited by Moderator>

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Answer 10

Bagarius

Level 1

0 points

Feb 13, 2009 2:14 PM in response to samarkham

I too have exactly the same problem on the same machine, a DP 2.5 GHz G5. Seems very, very strange that this thread is the only reference to the problem online and the only reports are from the past ~60 days. I have a little more to throw into the pot: I was experiencing extreme fan noise and ran into a thermal runaway sleep event. Temp Monitor showed a 20ºC spread between CPU A and CPU B, which suggests to me a faulty sensor. Online guides to the thermal runaway suggested an SMU reset, so I went ahead and followed SMU reset procedure with the button below the lower ram banks.
After this the machine has exhibited the odd (non) booting behavior, but only sometimes. It seems that if I let the machine sit cold for 30+ minutes cold before attempting a boot, I can get the thing started and functioning mostly normally. The one quirk I have noticed is DHCP does not work any more when the machine does boot. When it does not boot, it seems that I have TWO red LEDs illuminated on the logic board side of the processors, one high and the other low on the same depth plane. This cold just be me seeing things though -- staring through the grill, it could very well be a reflection (or me going insane).

Hope we can collectively find a solution (or diagnosis!).

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Answer 11

Feb 14, 2009 8:27 AM in response to Bagarius

its either the martians are here and the governments of the world won't tell us or the cold weather is some how producing condensation on chips.

i read a thread where a guy took hair dryer to his g5 for a couple of hours and it worked just fine.

so maybe its time to break out the de-humidifiers

"best guess"????????

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Answer 12

Samsara

Level 4

1,321 points

Feb 14, 2009 11:17 AM in response to Bagarius

This could just be me seeing things though -- staring through the grill, it could very well be a reflection (or me going insane).

After a while, it's both. I saw red lights for some time through the front grill and when I did my 2.7 would never start, it just idled until the fans started going, then I forced shutdown with the power button. Got to the point where I would just turn it off as soon as I saw the light, same difference and it allowed me to boot more times.
I thought I saw the lights in the back, near the PCI slots. Somewhere back there. But then opening and cleaning my mac one day I realized that couldn't be. The view back that far seems to be physically blocked in the compartment. So now, despite it still looking the same way, I think it must be a reflection of the lights of the RAM banks. That you and I can see those otherwise unlit lights is something I really don't understand. Lately I've been hearing of problems around RAM slots with the solder that is apparently used there. Cracking, coming apart, expanding, I'm not sure. I wonder if the red lights and that might be related.

The temperature difference and the booting problems may be related. One of your processors could be starting to go. What's the temp of CPU A when at both highest and reduced settings, in energy saver prefs? Your machine could be running too hot. The heat could be making the solder joints expand and screw with your RAM, which will definitely give you boot problems.
My 2.7 needed to cool down before I attempted to start it after I had just shut it down. A small fan through the front grill speeded the time. But while the 2.7 ran well for the most part it had definite heat issues and it seemed just a short time before it went. It sits ready should the unthinkable happen to this one.

Remember that heat problems are often related to dust built up in the mac, cooling fins especially, front and back vents, in and around RAM and PCI slots. Clean any dust you see.

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Answer 13

Feb 16, 2009 3:27 AM in response to Samsara

Another one to add to the growing list of sudden G5 failures.

This weekend, for the first time ever, my 2004 dual 2Ghz G5 had a kernel panic, but it restarted ok. My next move was to clone the startup drive out to a Firewire device and it booted ok from there, so I was able to check the startup drive from Disk Utility and it reported OK. Then restarted ok from the startup drive.

Ran for a while then it happened again. Restarted ok again.

Ran for a while and went again, this time reporting "system failure cpu0" and now won't run up, after a few seconds the fans come on and it just sits there.

Fortunately I was able to boot my Powerbook from the clone!

Have only found this thread this morning so I don't know yet about the red light.

Anyway, as investigation and repairs looks expensive and possibly ineffective, I'm cutting my losses and have just ordered a Mac Pro (I'd saved up for a new TV but that will have to wait 🙂 ). The lucky thing is, I was about to order new memory for the G5, and was considering a bigger HD and maybe a new graphics card while they're still available, but I hadn't got round to buying...that would have been a real ****

Message was edited by: Pat Taylor

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Answer 14

gleesinn

Level 1

0 points

Mar 21, 2009 11:26 AM in response to Pat Taylor

Doesn't appear anyone has any significant solutions. Some people recommend zaping SMU, replacing PRAM battery, cleaning dust etc. I guess it can be many things. I've had this problem off and on for about a year.

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Answer 15

Apr 19, 2009 9:28 AM in response to gleesinn

i just came across this thread after my G5 Quadcore which i purchased in jan 2006 and which has been running trustily since suddenly won't start. in my case there are 2 LEDs lit up one is red and a second which stays permanently on when the unit is plugged in is yellow. there is no start chime. the fans start wailing after about a minute.

i took apart the G5 and dusted etc. i had just performed a gig with the mac yesterday and was setting it back up. i can seem to remember a similar issue about a year ago when the G5 wouldn't start up, but each time before i was able to get the machine up and running.

after i reset the SMU i get a weird peep and the power light blinks 2x pauses then blinks 2x etc.

i hooked the unit up to my MacBookPro and using firewire mode got the G5 to start. contrary to the other tries, the startup chime came and i was able to access all my files no problem when the G5 was a fiewire drive. however after a brief glimmer of hope restarting the G5 it's now back to not starting. no chime, and no way to solve.

has anyone on another thread found a solution or answer? this machine is my bread and butter and i need it next week! i have been using macs for over 15 years and never had one die on me.

please help....

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