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The PowerMac G5 is a desktop computer first produced in 2003 by the Apple Corporation. This guide will review the repair process of an Apple PowerMac G5 model number A1047 EMC 2061 from 2004. It was discontinued in 2006 as part of the Intel switch first to developers then consumers.

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Fan speeds up by - mouse or graphic card / G5 2x2,5GHz

G5: PowerMac7,3

CPU: PowerPC G5 (3.0)

CPU-nol: 2

CPU-speed: 2.5 GHz

L2-cache (per CPU): 512 K

Memory: 4 GB

Busspeed: 1.25 GHz

Boot ROM-version: 5.1.8f7

Fan speed up when the mouse is turning.

I have previously believed that it was "Memory Heat Sink " - sensor that caused the problem.

It shows a temperature of 71-81 ° Celsius.

But when I "move" the mouse - the fans will increase as a consequence of this.

If I spin the wheel on the mouse to scroll a web page, it will increases the fans.

Likewise, if I drag the mouse back and forth over the Dock-menu.

In Bouth cases the MHS-sensor do a quick temp. increase - and I don't know - if the Temp. is affecting fan, or the graphic card?

The fan speed up problem - is - as I see it - not fully related to temperature, because sometimes Temp. is higher - without the fan speed up. The only sensor showing "hi" is Memory Heat Sink. Even when the MHS is colder - mouse makes fan to speed up. The CPU Temp. is around 50° C +- 5° with nervous behave in the temp. curves.

I also have notice that the temperature is wobbling, with +-1 ° / per second, with quick differences . The temp. Sensor Windows shows a nervous curve.

Could it be some kind of Capacitor-problem behind that???

(Is it possible to get map over the motherboard, showing the electrical spec)

How should I deal with this problem?

What Temp is normal from "Memory Heat Sink" - sensor ?

Do anyone have the technical spec 4 The Memory Heat Sink Sensor?? ( I believe that is a resistor temperature sensor)

Answer this question I have this problem too

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hej göran,

still working on the powermac ?

in my opinion is the graphics card the bad boy in the described case - since the mouse pointer is also work for the gpu - it could make some "problems" - maybe the heat sink of the graphics card is not well placed (the adhesive sometimes fails)

if i remember right, you wrote about your 3 powermacs - is it possible to change the graphics card with a working one of the other power macs ?

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This is my solution - and it makes stability to the fans "overreaction" who makes them running up and down.

I increase the step value of "MaxTempDeltaBeforeIncrease" from 20 to 40 in appleBlower.kext --> info.plist

Then i Lower the "fan-hysteresis-temp" and the to first step in "fan-speed-table" with 2°C in the AppleFan.kext --> info.plist.

The array's has to divided with 256 to get temp.

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First of all i'd reset the SMU by letting the computer unplugged for a few minutes and pressing and holding the startswitch for a few seconds before plugging it back in.

Also you could recalibrate the fan controls using Apple Service Diagnostic for Power Mac G5 - to be found here:

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hi karsten, göran is way beyond that point - but under normal conditions - i would agree.


OK, i didn't know


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Goran will be eternally grateful.
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