Service and troubleshooting
EST3 Installation and Service Manual 8.15
Table 8-7: Control / display module troubleshooting
Problem Possible cause
All module LEDs and switches
inoperative AND host module
working correctly
1. Ribbon cable between display and host module loose or
defective
2. Display not configured in SDU
3. Display defective
LEDs respond incorrectly 1. Display not defined in SDU database
2. LED misidentified in SDU database
3. Rule governing LED operation not correctly written
Switch activation does not
perform the required function
1. Display not defined in SDU database
2. Switch misidentified in SDU database
3. Rule governing switch operation not correctly written
Audio amplifier modules
Table 8-8: 3-ZAxx Zoned Audio Amplifier module troubleshooting
Problem Possible cause
Audio output level too low 1. Jumpers set for 25 Vrms when connected to a 70 Vrms
circuit
2. Gain adjusted too low
3. Input level to ASU too low
No or extremely low audio
output
1. Fuse blown
2. Gain set too low
Audio level too high 1. Jumper set for 70 Vrms when connected to 25 Vrms circuit
2. Gain adjusted too high
3. Input level to ASU too high
Amplifier current limiting 1. Audio circuit overloaded
2. Input level to ASU too high
Incorrect amplifier version
reported to CPU module
1. Jumpers installed incorrectly