GE Security EST3 Installation And Service Manual page 272

Service and troubleshooting
DS5 DS4
TB1-OUT
TB1-IN
DS1
TB2-OUT
TB2-IN
TB3
SIGA +IN- +OUT-
8.22
Table 8-15: SIGA-AAxx LED indications
LED Color
DS1 Yellow
DS2 Yellow
DS3 Green
DS4 Green (flashing)
(daughter board)
DS5 Red (flashing)
(daughter board)
Gain adjustment
With the amplifier connected to the speaker load, use the gain
adjust potentiometer (R116) to get a 25 Vrms or 70 Vrms signal
(depending on JP2 setting) with a 1Vrms 1 kHz tone at the
amplifier input. If a oscilloscope is used to adjust levels, use the
following peak-to-peak voltage levels:
• 25 Vrms = 71V
PP
• 70 Vrms = 200 V
PP
The amplifier must be connected to a load to properly adjust the
gain. In the event the actual speaker circuit can not be used, a
dummy load must be fabricated according to Table 8-16. The
wattage rating of the dummy load must exceed the output power
rating of the amplifier.
Table 8-16: Amplifier dummy load values
Output power 25 Vrms output
30 Watts 20.8 Ω   @ 30W
50 Watts 12.5 Ω  @ 50W
To maintain DC supervision and keep the amplifier out of
trouble while adjusting the gain, connect a 47 kΩ EOL resistor
DS3 DS2
JP2
Description
Power Amp Enabled
Backup Mode
Amplifier Active
Normal
Active Condition
70 Vrms output
167Ω  @ 30W
100Ω  @ 50W
EST3 Installation and Service Manual
TB4
NAC
TB5
BACKUP
TB6
+ 24V -
[3SIGAMP1.CDR]