Noisy PowerMac G5 Quad - LCS system?

[mayor686]

Hi, I own a PowerMac G5 Quad. It is very very noisy! I tried to execute the ASD calibration but nothing has changed. I tried to unplug all the fans to understand the cause of the noise. So the noise came from the power supply or the LCS system. Remove the power supply from the case is very difficult, so for now, I'm investigating the LCS system. I have the Dolphy LCS with two pumps. It is possible that the LCS system has some problem and the noise came from it? Can you suggest me some methods to understand if there are few liquids inside the system? I read some threads about the Air conversion from the 2.0 dual heatsink, what you think about it? Heatsinks are really enough for the G5 Quad?

Many thanks

 

[Eriamjh1138@DAN]

What kind of noise? Mechanical noise? Electrical noise? Hum? Whine? Squeak? Squeal? Buzz?

Does it vary with temp, fan speed, load, time, CPU temp, etc?

With these systems pushing 15 years old they need maintenance like an old car. It may be time to rebuild the LCS.

There are posts here and elsewhere on how to disassemble and rebuild the LCS. You should start reading up and plan on a weekend of rebuilding and possibly losing the patient.

 

[mayor686]

Idle:

This is the noise in idle -> Idle Noise

Full load

This is the noise in full load -> Full load noise

 

[NikolaPPC]

Greetings!

From my point of view, i don't think the LCS has failed. It doesn't perform as new, but it is far better thank a leaky one (this conclusion was only from the temperatures).

First of all, check if the backside sensor is interfering with ASD calibration because it has obviously failed and reports 3000 degrees celsius.
Second, check the fans while they are working, failed fan bearing can make a squealing noise. A little drop of oil on the bearing can fix this problem.
Third, to be absolutely sure, listen to the pump and hoses closely, check for any noise or bubbles in the system.


To do this all, open the side panel, remove the clear acrylic cover and on the bottom right side, put a piece of paper to trick the sensor that the acrylic cover is still there and doesn't increase fan & pump RPM to the max.

 

[z970]

A little drop of oil on the bearing can fix this problem.

I recommend silicone-based lubricants.

To do this all, open the side panel, remove the clear acrylic cover and on the bottom right side, put a piece of paper to trick the sensor that the acrylic cover is still there and doesn't increase fan & pump RPM to the max.

I can't speak for the pump, but the HDD bay fan does not kick up to max RPM like models prior to the 11,2s did when the wind deflector is removed.

 

[NikolaPPC]

I can't speak for the pump, but the HDD bay fan does not kick up to max RPM like models prior to the 11,2s did when the wind deflector is removed.

You are right, i totally forgot about that!

 

[Eriamjh1138@DAN]

This is the noise in full load -> Full load noise

I’d call that a whirry-grindy noise. I think that’s most likely fan beatings as said.
You should be able to isolate fans vs. the pump. You can gently stall the fans with a non-destructive or otherwise spongey tool, or jam them so they don’t spin up. Take all necessary precautions.

 

[philgxxd]

I find your CPU temps actually quite low, no worries at the moment.
I would say that memory controller is at a high temp. I had that too and did a an overhaul and repaste. I completely disassembled my quad to get to the backside of the logic board but was absolutely worth it.

See

Power Mac G5 Dust Out and Thermal Paste Re-do

Argh! I'm in the middle of cleaning my quad and I finally arrived to the back of the motherboard to take a look at the memory controller heatsink because I always get temperatures over 80°C from the controller even when idleing. But I can't get out the 3 white plastic pins. I'm even wiggling...

forums.macrumors.com

and my following posts in this thread.

 

[Eriamjh1138@DAN]

I find your CPU temps actually quite low, no worries at the moment.
I would say that memory controller is at a high temp. I had that too and did a an overhaul and repaste. I completely disassembled my quad to get to the backside of the logic board but was absolutely worth it.

i was going to say the same thing. Mine runs 60-70C. And it definitely needs a rebuild.

 

[mayor686]

Some other informations:
Open Mac In idle

ASD Test results

Calibrations

This noise near the LCS is normal?

 

[NikolaPPC]

Are you running your Quad in the reduced mode?
You probaby need a repaste if it hasn't been done before.

Cheers, Nikola!

 

[philgxxd]

I would say if there is a lot noise from the LCS there are probably air bubbles in the loop and you have to overhaul also the system that means to drain the loop and refill it.

 

[Macbookprodude]

basically, its a lot of work. You may want to try to find the single pump which was more reliable according to many sources. The dual pumps usually go bad.

 

[necreation]

I've put my power settings to "Automatic" and tried to play a youtube video in ArticFox. The temperature seems to be going higher than usual. Seems like I've always been running it in reduced mode.

Seems like I should do a LCS rebuild soon. Any advise on how to do this?

 

[mayor686]

Are you running your Quad in the reduced mode?
You probaby need a repaste if it hasn't been done before.

Cheers, Nikola!

• The reduced mode is enabled from the openfirmware? I use my quad also with Linux and the problem is the same.
• I can repaste, I will try.

I would say if there is a lot of noise from the LCS there are probably air bubbles in the loop and you have to overhaul also the system that means to drain the loop and refill it.

Is it possible to refill without remove tubes?

basically, its a lot of work. You may want to try to find the single pump which was more reliable according to many sources. The dual pumps usually go bad.

• If I can't solve, I want to buy another LCS. Which is the best? Dolphi with one pump or Panasonic?

• Can I use an older LCS model with one pump? A friend owns this model:
  and he can give me the LCS. Do you this it is ok for G5 Quad?

Even if the ASD test is ok in macos the backside sensor fails.
Do you think I can solve this problem or disable this sensor (in macOS or in Linux)?

Really thanks

 

[NikolaPPC]

The reduced mode is enabled from the openfirmware? I use my quad also with Linux and the problem is the same.

It can't be changed in Open Firmware, but can be changed in OS X (Settings > Energy saver > Options > Processor performance).
I don't know about linux (if it has any energy saving options).

Is it possible to refill without remove tubes?

It can be done via service port, but don't expect good results and draining & filling it that way will be a nightmare.

Another thing is that the dual pump Quad is much harder to repair than the single pump version.
I'll soon repair my Quad (single pump version) because the temps are going crazy and will make a step by step guide for that!

• If I can't solve, I want to buy another LCS. Which is the best? Dolphi with one pump or Panasonic?

You can't be sure that the other LCS will work as intended because they are over 15y old. They will start to fail sooner or later..

Can I use an older LCS model with one pump? A friend owns this model:

The LCS on that DP2.5 is much more prone to leaking than the Quad one and you won't be able to mount processors from the Quad on that LCS.

Why don't you check out how to convert you quad to air cooling, there is a good guide from @MrVitalic on this thread.

Even if the ASD test is ok in macos the backside sensor fails.
Do you think I can solve this problem or disable this sensor (in macOS or in Linux)?

I don't think that this is possible, but maybe someone knows more about that!


Cheers, Nikola!

 

[TzunamiOSX]

i would recommend removing the cooling system and checking for leaks and corrosion (also control between cpu and cooling plate. If there are no problems renew the thermal paste.

Possible problems i see:
-Pump is not working normally
-Not enough liquid inside the cooling circlular
-thermal paste bad

 

[necreation]

i would recommend removing the cooling system and checking for leaks and corrosion (also control between cpu and cooling plate. If there are no problems renew the thermal paste.

Possible problem i see:
-Pump is not working normally
-Not enough liquid inside the cooling circlular
-thermal paste bad

There's no visible leakage so far and I suspect the thermal paste is bad.

I have seen a few tutorials on how to service the LCS but never about just renew thermal paste. Is there any where I can find such tutorial?

 

[TzunamiOSX]

This is a conversion video, but it will help and show you also a location where the cooling circular can leak (you only need the first 6 mins. on min 9.00 is cleaning and thermal past).

To remove the CPU cover you must remove a little plastic pin. A good solution is a lighter like this:

Look the video first before start working (between 6:00 and 9:00 is a convertion path where parts must be destroyed, dont do this)

 

[necreation]

This is a conversion video, but it will help and show you also a location where the cooling circular can leak (you only need the first 6 mins. on min 9.00 is cleaning and thermal past).

To remove the CPU cover you must remove a little plastic pin. A good solution is a lighter like this:

View attachment 916206

Look the video first before start working (between 6:00 and 9:00 is a convertion path where parts must be destroyed, dont do this)

Interesting.
I do have some spare Dual CPU G5 around that I might can use for conversion. But before that I better open it up to check for corrosion. Open it up to renew thermal paste don't seem that scary after watching this video. Thanks for the info.

 

[mayor686]

Good news no leaks!

Ok, I repasted CPUs.

And I reassembled all components.

Now PowerMac don't want to boot. If I press Option the boot menu is shown but in few seconds it stucks.

Any ideas? Tomorrow I will try to disassemble it again.

thanks

 

[NikolaPPC]

Don't overtighten the processors screws, check for bent pins, check if it seated evenly and correctly!

Cheers, Nikola!

 

[TzunamiOSX]

Good news no leaks!

View attachment 916394 View attachment 916395


Ok, I repasted CPUs.

And I reassembled all components.

Now PowerMac don't want to boot. If I press Option the boot menu is shown but in few seconds it stucks.

Any ideas? Tomorrow I will try to disassemble it again.

thanks

CPU A must be CPU A, and B must be B. Sure that you put both CPUs to his old place? Did you add the thermal paste correctly? What paste did you get? I hope the paste does not conduct electricity.

 

[NikolaPPC]

I use Artics MX-4 and i recommend thst paste to everyone!

Cheers, Nikola!

 

[TzunamiOSX]

I also use Artics MX-4.