Fan Problem - New Motherboard???

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Level 3

838 points

Fan Problem - New Motherboard???

My Power Mac G5 is about five years old. It has had the motherboard replaced twice in it's life time. Towards the latter part of the five years, the dreaded fan roar has popped in and out.

I have done the usually steps, reset PMU (without the power cord attached), repair permissions and disk, ran OnyX, clean the dust from within the casing and all around the fans. Usually some thing gets rid of the fan problem. Of course there is no real clear indication what did it.

Otherwise, never really much of a problem since it disappears for long spells. In the last two days it has been harder to get the fans back to normal.

I ran TechTool Pro and it some how temporarily quieted the fans. But it came back after waking the G5 from sleep after a couple of hours. Right now it is quiet.

I read somewhere as one solution to the fan problem that running the Apple Hardware Test is suppose to reset the fans to the factory default. I am not sure if that is true or not. I ran the Apple Hardware Test (V2.2.1). It produced an the following error message about the motherboard:

**ERROR*CODE***ERROR*CODE**
2FAN/4/7" Fan For DRIVE BAY
post/192/0
**ERROR*CODE***ERROR*CODE**

Does does it mean the components on the motherboard that controls the fan in the drive bay has finally gone bad?

PowerMac G5/Dual 2.0 GHz, Mac OS X (10.5.6)

Posted on Jan 15, 2009 7:27 PM

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Answer 1

JeffDy

Level 1

5 points

Jan 16, 2009 1:53 AM in response to Carlton Chin

Hello,
Fans will probably be resetted when doing a thermal calibration again. Do a search to find the Apple Diagnostic Software in order to do that.
Did you checked that the fan itself is running? And if it's noisy, maybe it needs to be replaced. You can buy it mail order: http://www.mac-pro.com/s.nl;jsessionid=0a010c451f431bae17d26187434aadc89eca6a1d7 a7a.e3eTaxiMa38Te34Pa38Ta38Nch50?sc=2&category=408&it=A&id=2332 or somewhere else
You will have to take the whole machine apart to do that...
Hope it helps

Jeff

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Answer 2

Carlton Chin Author

Level 3

838 points

Jan 16, 2009 6:23 AM in response to JeffDy

It is hard to tell where most of the fan roar is coming from. I think it is coming from the drive bay area (or maybe at the rear of the G5??).

If I wanted to see if the noise is coming from the drive bay, would removing the plastic fan assembly at the front and rear of processor for a few seconds be a bad thing?

The Mac OS X Install CD that originally came with the G5 only had the Apple Hardware Test on the same CD? But I did not see anything labeled Apple Diagnostic Software. What does the disc look like?

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Answer 3

Carlton Chin Author

Level 3

838 points

Jan 16, 2009 10:55 AM in response to Carlton Chin

Okay, I did a little more research. The Apple Service Diagnostic CD is not available to the public. So how can I execute a thermal calibration? Is there a utility out there just for that purpose?

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Answer 4

JeffDy

Level 1

5 points

Jan 16, 2009 12:57 PM in response to Carlton Chin

Hello again,
The machine works without the front CPU fans, no problem. Removing the back fans is impossible without removing both processors and i didn't test.

Maybe there's something else...
There are 2 fans in the "noisy" place. The one you see (for HD) and the one you don't see behind...

This kind of fan (not the same kind as the others) is A real dust trap, even more in smoke and dust. Maybe you can check with a mirror after removing the hard disk(s) to see if yours is clogged. There's as small opening in the back, next to the HD fan. A lot of chance it is. It's mounted on rubber. If then, you have to take apart the whole machine to remove it and clean it.

Jeff

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Answer 5

Carlton Chin Author

Level 3

838 points

Jan 16, 2009 6:45 PM in response to JeffDy

If you are looking straight on, there is the fan with the metal grill to the left and just to the right are the drive bays. Just beyond that fan, I recall seeing some kind of structure. Was not sure what it was and I did not see anything resembling plastic blades that look like a fan. Is that the area you are referring to or Is the fan directly behind the drive bays?

How much of the hardware do I need to remove to get to that area? The fan with the grill? The bay that support the drives?

Just want to make sure that I do not remove something that would cause permanent damage or require special tools that only a technician would have? I already can see I need a real short philips screwdriver to remove the screw from the under side of the fan with the grill.

Message was edited by: Carlton Chin

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Answer 6

JeffDy

Level 1

5 points

Jan 17, 2009 11:02 PM in response to Carlton Chin

Hello

You have to remove everything inside the box. And you'll need the right tools
to do that. And some skill.

Did you check the fan?

Jeff

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Answer 7

Carlton Chin Author

Level 3

838 points

Jan 20, 2009 5:39 AM in response to JeffDy

I was all out of compressed air to help with clearing the dust. Did not make sense to open up the G5. So I ended up putting up with the fan noise for a few days. I finally got a can yesterday.

The machine has been quiet yesterday and this morning. Does it still make sense to open it up? I am am afraid to do something that would inadvertently start the problem up. You know, "let sleeping dogs lie."

BTW -- Are there inexpensive vacs appropriate for cleaning the inside of computers that actually work or would it create static of some kind?

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Answer 8

direwolf8

Level 4

1,286 points

Jan 20, 2009 10:46 AM in response to Carlton Chin

Are there inexpensive vacs appropriate for cleaning the inside of computers that actually work or would it create static of some kind?

A good vacuum cleaner can pull enough air across a plastic hose or accessory to ionize the air and generate a high voltage. Mine will light up an NE-2 neon lamp just holding the crevice tool near it (and it's a 40 year old Silver King). Don't do that inside your computer!

Typically we clean computers with compressed air. Use a blowgun a about 20 PSI pressure and blow the dirt out and away from the places where it gets trapped. The benefit of blowing air rather than using a vacuum is that you can cover a larger area without having to get your vacuum pickup in every crevice, and you won't generate the high volume of air over a very small area that can cause the ionization that can damage components.

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Answer 9

Carlton Chin Author

Level 3

838 points

Jan 20, 2009 11:39 AM in response to direwolf8

How do you wipe away areas that compress air can't remove dirt from and without worrying about static charge (e.g. motherboard)?

Also, the fans just kicked in but I am wondering if Safari triggered something. It seem to started acting up when I began surfing. Is there a way to check some kind of logs and if so what am I looking for?

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Answer 10

Carlton Chin Author

Level 3

838 points

Jan 20, 2009 2:13 PM in response to Carlton Chin

Okay I was able to clean the area around the bays but most of the dust was on the fans to the left of it.

It was quiet when I booted up but a few minutes later the fan is speeding up and slowing down. Up and down.

There is a small chip located just above the drives bay. Is that the thermo sensor? I think that is an odd place to put it especially if you have two drives installed.

Any other thoughts on this?

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Answer 11

Carlton Chin Author

Level 3

838 points

Jan 21, 2009 7:22 AM in response to Carlton Chin

Just wondering....aside from thermo calibration, does it makes sense to install another fan inside the G5. I think there are kits for this.

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