Power Fail - GE PANDA Service Manual

Chapter 1: Functional Description
System Functions
FIGURE 1-7. Battery Management

1.3.5 Power Fail

The next paragraph assumes loss of AC power and resulting loss of DC power.
A power fail is detected when the audio processor (refer to Figure 1-8) senses the 3.3 Volt power supply
below normal operating level with the stand-by switch on. This will result in a shut down of the main
application processor and initiate a power fail alarm for a minimum of 10 minutes. The lithium ion battery or
the "super" capacitor provides power for the alarm. The audio signal for a power fail alarm is a repeating
sequence of 3 beeps from a piezoelectric buzzer on the Alarm Light Board. The visual signal is one LED on
the Alarm Light Board.
The heat control processor on the Power Board has an independent circuit to detect a drop in 12 Volt power
below normal operating levels. In the event of low 12 Volt power the heat control processor will initiate a
controlled shutdown of the heater circuit. In the event of an internal malfunction resulting in loss of one
level of DC power, one or more of the processors will shut down causing the smart monitoring function to
initiate a system failure.
Service Manual 1-13