Nokia 500s Installation Manual page 121

The power supplies are autosensing and can accept input voltages between
85 VAC and 264 VAC. The power supply output is regulated to a tolerance of
± 5 percent of the specified output voltage.
Under certain circumstances, the power supplies feel hot to the touch. This
happens when the power supply is connected to AC power, but is not turned
on. In this state the 3.3 V standby circuitry is powered on, causing the power
supply to heat up. Because the power supply is not turned on, the integrated
cooling fan is not operating.
In this situation, the power supply still meets all safety standards.This
condition is normal and does not affect the performance of the Nokia 500s
appliance. To cool the power supply down, use the power supply switch to
turn on power and activate the integrated cooling fan.
Caution
The Nokia 500s power supply might be hot to the touch when the
power supply unit is plugged in to an AC power source and the
power supply is not turned on
AC power receptacle
Power supply A
Power supply B
Nokia 500s Installation Guide
Integrated power supply
cooling fans
Installing or Replacing a Power Supply
Power supply switches
00308a
121