Chapter 7: Service and troubleshooting
EST3X Technical Reference Manual 173
Table 39: Power Supply troubleshooting
Possible cause
(< 20 V) • There is an excessive load
Batteries will not charge
• The system is in alarm mode
• The NAC/AUX outputs on the power supply are configured
for AUX and are loaded with more than 6.0 A
• The wrong battery type is configured in the 3-SDU
• The battery is shorted
• The battery is not wired correctly to the PS10-4B
System will not operate on
batteries
• The battery voltage is low
• The batteries were connected before AC power was
energized
• The batteries are defective
SFS1-CPU Main Board troubleshooting
The SFS1-CPU controls all the communication and processing of information for
modules located in its cabinet. EST3X life safety network communication
between SFS1-CPU modules in other cabinets is also processed by the
SFS1-CPU.
Network communication is RS-485 when a 3X-NET8 or 3X-NET RS-485 network
option card is installed in the SFS1-CPU or fiber optic when a 3X-FIB8 or 3X-FIB
fiber network option module is installed.
The SFS1-CPU main board provides several LEDs that indicate activity on a
communication path. See Figure 44 on page 174 for the LED locations on the
main board and Table 40 on page 174 for LED descriptions.
Note: If an SFS1-CPU is defective, the entire SFS1-ELEC must be replaced.
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