Quad G5 issues

So aside from the overheating issue, my Quad G5 Hs]as started having other issues:

1) 2 of my 3Gb of RAM have disappeared (yes, they are paired properly) I can't detainee if it's the RAM or if it's the slots because of #2:

2) When I shut the Mac down I have to unplug it and leave it unplugged for upwards of 30 min before it will successfully boot again. Otherwise i may get as far as the Apple boot screen, spool the fans up to warp speed and howl like a jet airliner, and nothing else. When this happens, warning lights 2 and 6 on the front of the Mother Board (right by the upper RAM slots) illuminate. Apple says if they light up to contact Apple, obviously meaning you have big issues.

Once the machine is running it works fine, just with 1Gb of RAM vice 3.

Now, the RAM aside, I'm thinking maybe a power supply issue in the machine is the cause of #2.

Anyone else ever seen anything like this? BTW, the machine is 5 years old, out of warranty so the odds of getting it fixed at less cost than a new MacPro are slim.

without wanting to sound obvious have you tried removing & reseating your ram?
i fired mine up the other day, no chime & it was only showing 1 out of 7Gb of Ram!
reseated them all again & then it fired up fine, chimed on startup & all ram showing in system profiler.
although i then left it for a while & came back to it with the fans going full chat & it wouldn't respond to keyboard or mouse & the display was blank!!
unplugged & fired up again, chimed as normal but had an onscreen message about a kernel panic that i should have read before i closed the box!
although when tested for a short time it all worked perfectly??

when it did this before i used the Apple ASD test disc which really works your machine & it failed some of the ram. even though the initial test on startup gave the chime & system profiler etc said they were there & working ASD found some problem or other.
this leads me to believe that the G5's are either really hard on ram or they are prone to having problems with the slots. which isn't good as they're part of the logic board

anyway remove your ram, give it a wipe, blow out your slots, reseat & try again & let us know how you get on ?

if its a power supply they generally just die & stop working completely!

baggss said:

Anyone else ever seen anything like this? BTW, the machine is 5 years old, out of warranty so the odds of getting it fixed at less cost than a new MacPro are slim.

Click to expand...

This may be a long shot...but have you cleaned the inside lately? Dust, dirt, and fuzz can really clog up the heat-sinks (video card) & fans inside the G5's...you would be really surprised where & how much fuzz can collect in all of the "nooks & crannies...including inside the power supply itself!

Being a quad G5...even with the liquid cooling system I'm guessing it still runs pretty warm. So a dirty computer will run even warmer.

HTH,

- Nick

sabot said:

although i then left it for a while & came back to it with the fans going full chat & it wouldn't respond to keyboard or mouse & the display was blank!!
unplugged & fired up again, chimed as normal but had an onscreen message about a kernel panic that i should have read before i closed the box!
although when tested for a short time it all worked perfectly??

Click to expand...

That's exactly what it's doing.

I generally keep the inside of the machine clean, I learned shortly after getting this machine that it needed that. I've reseated the RAM, swapped it around etc, but can't tell if it's the slots or the RAM itself for the reasons I originally described. I can't run the Hardware test disc since I have an overheating issue with CPUA that will shut the machine down when the test runs due to heat.

in that case i'll let you know how i get on with fixing mine then.
my mrs is a Mac engineer & she'll be helping me diag & repair my machine so i'm not just blundering around in a blindfold ;D
so far though my experiences lead me to the ram/slots more often than not!
i've got handfulls of ram sticks here that chime but fail ASD alongside others that have passed ASD in another machine but fail in mine but work perfectly in another slot???
it seems to pick a slot at random then go into spaz mode!
i'm not around this weekend so i wont be getting into it until next week but i'll let you know what i find, keep us updated on your progress on here as somebody else maybe able to offer an insight ;D

baggss said:

I generally keep the inside of the machine clean, I learned shortly after getting this machine that it needed that. I've reseated the RAM, swapped it around etc, but can't tell if it's the slots or the RAM itself for the reasons I originally described. I can't run the Hardware test disc since I have an overheating issue with CPUA that will shut the machine down when the test runs due to heat.

Click to expand...

Just one more long-shot question. I know that some folks with the G5 towers had problems with the liquid cooling system...any leaks on your end?

I'm assuming you would know...due to the leakage...but wanted to ask just in case.

- Nick

No leaks that I can see. I even opened up the CPU/Pump compartment and there is no sign of leaking. I'm assuming it is a heat paste issue or a clog in the CPU A cooling loop. I was supposed to get a MacPro to replace this machine but recent events will force me to delay for probably another 6 months so need to eek out as much life from this thing as I can.

baggss said:

So aside from the overheating issue,

2) When I shut the Mac down I have to unplug it and leave it unplugged for upwards of 30 min before it will successfully boot again.

Click to expand...

You mentioned the over-heating issue in your initial post...seems to me if a computer is over-heating...this could lead to some of the other issues you're experiencing.

Have you downloaded & installed a program like "Temperature Monitor":

Temperature Monitor: Description

...and see what sort of temps your computer is generating??

This could definitely give you some insight as to what may be causing the issues (where the over-heating is occurring)...and help you determine if anything you're doing to help with cooling is successful.

Hope this helps,

- Nick

that looks like a good tool Nick


i have istat which tells me about temps & fan speeds etc but i might give that one a go too

sabot said:

that looks like a good tool Nick

i have istat which tells me about temps & fan speeds etc but i might give that one a go too

Click to expand...

iStat looks like a pretty interesting program as well:

iStat Menus, a Mac app by iSlayer

Thanks for mentioning it,

- Nick

pigoo3 said:

You mentioned the over-heating issue in your initial post...seems to me if a computer is over-heating...this could lead to some of the other issues you're experiencing.

Have you downloaded & installed a program like "Temperature Monitor":

Temperature Monitor: Description

...and see what sort of temps your computer is generating??

This could definitely give you some insight as to what may be causing the issues (where the over-heating is occurring)...and help you determine if anything you're doing to help with cooling is successful.

Hope this helps,

- Nick

Click to expand...

I've been running Temperature Monitor for some years. In fact the lite version resides in my task bar.

With the CPUs set to "Automatic" CPU A idles at about 140F, CPU B 109F. If I stress the CPUs running an App like Handbrake (that maxes all 4 CPUs) CPU A will zip to 208F and B will stay at about 150F. At that point the machine goes to sleep and the fans will spin up. If I leave it long enough it will come back, but it's generally easier just to restart it.

Yeah, it's got a heat problem, I know that, that's why I'm going to replace the machine. I'm assuming it's either the heat paste on CPU A or a clog in the cooling loop for CPU A. This could be related to my current issue, CPU A maxes at about 155F when the the CPUs are set to "Reduced" and stressed, except that the CPUs are not stressed or running hot (relatively speaking in regards to CPU A) when I shut the machine down and they don't get overly heated or stressed upon boot up, at I have never observed them to be when the machine boots.

There's a Mac shop locally (not an Apple Store) that I can probably take it to and have them diagnose the whole thing. I know in the end it's not going to be cheap or worth the effort to fix. At least they won't charge me to diagnose it.

baggss said:

I've been running Temperature Monitor for some years. In fact the lite version resides in my task bar.

Click to expand...

Ooh well...if you're already running Temperature Monitor...then you are certainly aware of your operating temps.

Since you're having trouble with the ram...is Temperature Monitor reporting any ram temps? I know with some desktops/laptops...sometimes Temperature Monitor will report ram temps...sometimes by "bank or slot".

Maybe if there is some ram near the hotter CPU A (I'm not familiar with the logic board design of a Quad G5)...it's getting extra warm...and causing issues with that ram.

Again...just trying to think "out-loud" and maybe "stir-up" a "cause-effect" relationship.

- Nick

p.s. By the way...that possible clog in the cooling loop for CPU A...is there any way of removing the possible clog or is the only solution the expensive "replacing the cooling loop" option?

baggss my 2.3GHz Dual Core at idle, iStat shows CPU A at 110 degrees and CPU B is also 110 degrees, so sure sounds like heat paste cracked on CPU A. Why not try replacing the paste with Arctic Silver?

harryb2448 said:

baggss my 2.3GHz Dual Core at idle, iStat shows CPU A at 110 degrees and CPU B is also 110 degrees, so sure sounds like heat paste cracked on CPU A. Why not try replacing the paste with Arctic Silver?

Click to expand...

Have you looked at the cooling system on a Quad G5? There are two separate liquid cooling loops that sit atop the CPUs inside a sealed compartment. Servicing them is a serious challenge at home and isn't really feasible. You have to disassemble (and drain) both cooling loops, remove the pumps, then remove the heat sinks to even get to the CPUs. Then you have to put it all back together and hope it works.

So after spending the better part of the day today troubleshooting these issues I discover that 4 of the 512Mb pairs of RAM (2Gb) were in mismatched pairs. In other words both pairs from maker A were in upper slots 2 & 3 and both pairs from maker B were lower slots 2 & 3. When I swapped them so they matched up all 3Gb of RAM showed back up. Much better.

Still nothing new on the not booting or heat issues, but at least my machine runs normally now. 1Gb in this thing was SO not enough RAM. It seems to take between 30 and 45 min of being unplugged for the machine to boot up normally. Now when it does boot, no error light on the Motherboard (as described in my initial post) illuminate though.

baggss said:

Still nothing new on the not booting or heat issues, but at least my machine runs normally now. 1Gb in this thing was SO not enough RAM. It seems to take between 30 and 45 min of being unplugged for the machine to boot up normally. Now when it does boot, no error light on the Motherboard (as described in my initial post) illuminate though.

Click to expand...

Congrats on figuring out the ram issue...but if the ram was mismatched...how well did the ram work previously when the computer was running ok?

I'm curious...if you start up this computer when it's "stone cold" (hasn't been used for many hours):

1. How long can you use it (hours or minutes) until something "bad" happens?
2. What exactly happens? Does it:
- just lock-up/freeze
- do you get a kernel panic
- does it just shut down on it's own?

Thanks,

- Nick

The RAM issue was caused by me when the booting issue first began. I started removing RAM believing I might be having an issue with the fist sticks and when I put them back I mismatched them. When it finally did boot and I only had 1Gb showing, I assumed some of it had gone bad. Unfortunately I just had to wait until I had a day (and the patience) to TS this properly to realize I had messed that up.

Once the machine is running it runs fine. I haven't had any errors or issues while it's in operation, as long as I keep the CPUs throttled back. The issues start if I set the CPUs to Automatic or Highest and stress them. In those cases the heat issue takes about 30 seconds to happen and the machine just goes to sleep and the fans kick to high speed. If I leave it long enough it will wake up, but we are talking hours here. Force rebooting is just easier.

The booting issue just started the day I posted this thread. In those instances error light 2 on the board will come on sometimes followed by the screen getting to the white Apple boot screen (but not going any further), sometimes not, followed by error light 6 on the board coming on. Once that happens the fans kick on high and the machine has to be forcibly shut down or unplugged. My feeling is still that this is a board and or power supply issue. If it were a HDD issue, the machine wouldn't boot normally when it does boot. Disc utility finds no software errors once it is running either.

I can normally leave the machine running for 30+ days with no real issues (my record is 167 days), I generally only reboot for software updates that require it, otherwise I either turn the monitor off at night or return it to the login screen (without logging out). If I go out of town on business for more than a few days I will shut the machine down just to save on electricity. Haven't had a Kernel Panic or a lockup in a few years now, so the machine itself runs just fine if I don't jack with the CPU settings.

baggss said:

Once the machine is running it runs fine. I haven't had any errors or issues while it's in operation, as long as I keep the CPUs throttled back. The issues start if I set the CPUs to Automatic or Highest and stress them. In those cases the heat issue takes about 30 seconds to happen and the machine just goes to sleep and the fans kick to high speed. If I leave it long enough it will wake up, but we are talking hours here. Force rebooting is just easier.

The booting issue just started the day I posted this thread. In those instances error light 2 on the board will come on sometimes followed by the screen getting to the white Apple boot screen (but not going any further), sometimes not, followed by error light 6 on the board coming on. Once that happens the fans kick on high and the machine has to be forcibly shut down or unplugged. My feeling is still that this is a board and or power supply issue.

Click to expand...

When you say you think that it could be a power supply issue...do you mean the actual power "supplied" by the power supply...or the power supply fan is faulty?

If it's a board issue...what specifically would you guess that it is?

I guess where I'm leading is (unless it's the PS fan)...your computer seems to work too "normally" for too long of a time with the CPU's throttled back to be either the PS or the board. And when you set the CPU's on Auto...then the computer is generating enough extra heat to cause it to shut down...so it seems to be the extra heat is the problem...not a faulty piece of electronics.

It really seems to me that everything points towards an overheating issue. I know that you have also already suspected that the problem is the partially clogged liquid cooling system or the CPU heat paste.

These two possibilities I know are fairly involved to troubleshoot...but if one or both are the problem...then fixing them has got to be done...a pain in the butt or not!

If one of these two problems really are the issue...that's still a lot better than a bad logic board.

- Nick

I guess the obvious question would be: What changes if I leave the machine plugged in as opposed to unplugging it that would cause it to not start? Seems like no power to the Power supply would cool it down and thus supply proper voltage to the machine during the boot process. Then again, I do get the happy Mac chime before it stalls in the boot process, so there is at least correct voltage for the initial start and hardware checks.

In researching the startup issue, I've read similar stories with similar problems where the Power Supply itself was the issue, not the fan. That's what I am basing my assumption on. The fact that I have to unplug the machine for up to 45 min then plug it back in to get it to boot leads me to also believe the PS is at fault. If I could leave it plugged in and it worked it would be different. This machine makes a large power draw when you boot it and it will occasionally pop the breaker in the room where it is located. Now granted, I only have about 50 things plugged into various outlets in this room, and the machine itself is plugged into a 24 outlet power-strip, so there is always a big draw in this room and sometimes even the vacuum cleaner will trip the breaker.

As for specifics on a board issue in regards to the startup issue, I have no idea to be honest.

I agree that that the CPU heat is a problem, but I am not certain it is directly related to the startup issue. Whatever is causing the heat issue, I'm not sure it is worth tackling. The machine itself is 5 years old and the PPC architecture is pretty much dead. I can't upgrade the OS past 10.5.8 and as time goes on more and more software will be Intel only. Given all of that, and the fact that I can live with the heat issue for the near term, it's probably best to just replace the machine all together. My bottom line is as long as I can reasonably rely on the machine for the next 6 months, I'll just replace it. Right now that looks like it's the case.

All that being said though, I'm going to be out of town for a week soon and I may drop the machine off with Apple and let them see if they can figure out what is going on. There was a recall of some of the G5 Power Macs some time back and even though mine didn't qualify maybe I'll get lucky (a pipe dream, I know). I know I mentioned the independent Mac store in my area in an earlier post, but they actually want MORE than Apple to TS any issues, and then they'll only give you an hour.

EDIT: Video card? http://macosx.com/tech-support/g5-startup-problem/8664.html

I actually have reset the PMU, but probably need to boot into open firmware and reset everything as is talked about in that article. I wonder if it will even boot into OF?