Haygar I think your reasoning is very sound. I was just going to post my thoughts after reading most of the topic/replies when I read your reply. I think we reached the same conclusion.
The following will provide some background of typical fan speed control circuits employed in a PC and likely the method employed on the Xbox 360 motherboard:
TEMPERATURE MONITORING
The prerequisite for intelligent fan-speed control within PCs is the ability to measure both system and processor temperature accurately. The temperature monitoring technique used has been the subject of many articles (for example, see Analog Dialogue 33-4.) and will only be briefly visited here. All Analog Devices system monitoring devices use a temperature monitoring technique known as thermal diode monitoring (TDM). The technique makes use of the fact that the forward voltage of a diode-connected transistor, operated at a constant current, exhibits a negative temperature coefficient, about -2mV/°C. Since the absolute value of VBE varies from device to device, this feature by itself is unsuitable for use in mass-produced devices, because each one would require individual calibration. In the TDM technique, two different currents are successively passed through the transistor, and the voltage change is measured. The temperature is related to the difference in VBE.
In any CPU, the most relevant temperature is that of the "hot spot" on the die. All other temperatures in the system (including the heat-sink temperature) will lag the rise in this temperature. For this reason, practically every CPU (manufactured since the early Intel Pentium II processors) contains a strategically located transistor on its die for thermal monitoring. It gives a true, essentially instantaneous, profile of die temperature.
From:
http://www.analog.com/library/analogDialog...ives/34-04/fan/ It is resonable to believe that the xbox 360 motherboard employs a similar circuit/method to monitor temperature and control fan speed. The circuit would obviously be on the motherboard and the voltage going to the positive terminal on the fan connector is being varied from 3 to 12vDC.
The 12v fan mood is designed to supply 12v directly to the positive wires of the DC fans. The mod involves cutting the positive wires and supplying 12vdc directly to the fan. As some one stated in a previous reply to this thread the xbox 360 fans do not have a 'voltage sense terminal thus the fan itself is not involved directly in reporting fan speed. The 12vDC fan mod does not disable or bypass the temperature monitoring circuit on the xbox 360 motherboard. Therefore the temperature monitoring circuit is still varying the voltage supplied to the positive terminal on the motherboard fan connector and thus still reporting that the fan speed varies. If you were to have performed the 12vDC mod by just nicking the insulation to the positive wires and supplying 12vDC from another source then the fan speed would be reported as 12vDC or full speed fan operation. Based upon this I find it extremely unlikey or impossible that a properly done 12DC fan mod could ever be responsible for a ban.
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Topic: Xbox Live ban updates (Read 1128 times)