Fan Control
The fan is connected to +15 VU over a speed control circuit. It
is only ON if a control signal from the processor is present.
The first 8 mi nutes after power-up the fan will run at a fixed
speed, fed with +8.3 V. After that the fan is temperature con
-
trolled. The processor reads the temperature from U39 via the
I
2
C bus. Depending on the temperature, the fan is fed with a
DC voltage between 8 and 13.5 V. The processor uses a PWM
signal that is filtered to control the fan.
Troubleshooting 6-7
Figure 6-4 Important power supply locations #1.
Figure 6-5 Important power supply locations #2.
To Next Page
Loading...
