Thermal Calibration "CPU intake fan speed error. Check that inner door..."

Question

Thermal Calibration "CPU intake fan speed error. Check that inner door..."

Has anyone gotten to the bottom of this error? I see lots of discussion of a possible bug in ASD thermal calibration and claims that it can destroy the eeprom that stores the calibration info on the logic board.
So what's the bottom line here?
Does this error in reality indicate that the eeprom is no longer writable?
Could this simply be an issue of the inner door not sealed properly (perhaps this calibration is critically sensitive to this)?

The fans are racing as intended since the CPU's have been replaced and the calibration stored on the logic board is no longer correct. Everything is fully functional and passes all tests. The inner shield is in place and the sensor (for the rightmost tab) sees it there. The intake fan is running. I also tried another fan with no change. I suspect that some overly high sensitivity to the fan speed is not really the issue here.

I currently have ASD 2.5.7. The notes for 2.5.6 include "Slight modiﬁcations to Thermal Calibration.", so I'm using that newer version. I thought the only change was removing the restrictions for allowing running it. I see reports of success using this version so there must be some hardware related issue here.

dual 2.5 G5 (4G RAM); 2.4GHz MBP (4G RAM); 1GHz TiBook (1G RAM), Mac OS X (10.5.6)

Posted on Mar 7, 2010 1:21 PM

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Answer 1

Mar 8, 2010 11:53 AM in response to Jim Newhouser1

Dear Mr. Newhouser,

This error message suggests the white sticker in the last tab of the inner transparant door is missing or the sensor looking for the reflection coming from that sticker (that sensor board is located beside the PSU) is failing. You can test the sensor by sticking a white piece of paper in the tab slot: if the sensor is o.k., the burning red LED on the logic board should go out.

After you've convinced yourself the parts referred to are functioning as they supposed to do, replace the inner door and execute the thermal calibration. For your 2.5 GHz dual processor G5 the ASD version 2.5.7 is good enough.

And yes, there are some reports coming from Apple technicians indicating the calibration software has a serious bug resulting in a permanent failure of the the regulating chip on the logic board. You should realize the ASD software is intended to be used by Apple technicians who usually have replacement boards at stock, so if one breaks down during calibration it's replaced instantly.

On the other hand, if you don't calibrate, the fans will stay blowing at full speed all the time. It's just a matter of taking the risk.

I hope your logic board is not already damaged by earlier calibrating attempts.

Best of success and regards,
Robbert

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Answer 2

Mar 9, 2010 10:41 AM in response to Mechanic man

The sensor is working. The red led comes on when the shield is removed.

Can you shed any more light on this? I see other people stuck with this and getting this same error message.
I've had experience before with programmable chips that are a bit flakey and need slightly different power for write mode. Could that kind of madness be going on with these logic boards with the ROM chip in question (as opposed to actual damage)? Or is it more of a trick with setup conditions (temperatures, etc). If this is actual damage, will a damaged logic board still pass all factory tests? I think the test only ran for about 3 or 4 minutes (for each CPU) before erroring out. Is this a clue?

Message was edited by: Jim Newhouser1

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Answer 3

Mar 9, 2010 12:48 PM in response to Jim Newhouser1

Dear Mr. Newhouser,

The G5's thermal management system is rather complicated indeed: the OS monitors temperatures and power consumption and reports fan speed adjustments to electronics called the Fan Control Unit. Maybe this link will provide you with some answers.

The transparant deflector door is only there for one reason: the bump protruding into the PCI zone guides the cool air over the NVidia GeForce 6600 Graphics card's heatsink, which is lacking a dedicated fan of its own.

What I did understand from the reports a few somewhat frustrated certified service technicians provided, the apparently not solved bug on the ASD disks damages the chip on the logic board in such a way that as a result it permanently will not accept any information at all. In some instances for a single repair three logic board replacements were necessary after thermal calibration failed. As a result, some service centers consequently skipped calibration, predictably resulting in frustrated customers getting mad from their 'repaired jet enigines'. Detailed technical information?... well, you know Apple!

I hope you're able to find the cause of the problems you're confronted with.

Best regards,
Robbert

Message was edited by: Mechanic man

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Answer 4

Mar 9, 2010 3:23 PM in response to Mechanic man

Yikes!
Well, thanks for the info.
I'm hoping someone can tell me if this error message is indicative of a damaged board. Of course what I'd rather hear is that instead, this means there's some setup trick to the calibration.

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Answer 5

BDAqua

Level 10

250,259 points

Mar 11, 2010 12:51 PM in response to Jim Newhouser1

Not that I advise this, nor does it even look like it's for the 2.7, but I found it interesting.

Device driver for the fan controller of the Apple G5 "PowerMac7,2"...

http://svn.gnumonks.org/trunk/g5-therm/new-kernel/fcu.c

CPU temperature and hardware sensor readouts in bash UNIX ...

http://www.macosxhints.com/article.php?story=20051021115356696

This patch makes the temperature control code more robust, putting

less pressure on i2c, and work around occasional misconfiguration
of the ADC chips leading to incorrect temperature readings...

http://lkml.indiana.edu/hypermail/linux/kernel/0403.1/0846.html

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