Chapter 7: Service and troubleshooting
P/N 3101890-EN • REV 006 • ISS 21JUN18 139
Label Source Description
Battery Internal Resistance Trbl PS10-4B Battery is degraded
Demux Audio Input ACHS The digitized audio data is missing
Waiting for SDU Download DACT A database download from the VM-CU is in
progress or incomplete
NAC Charge Pump Trouble PS10-4B • The charge pump for the NACs is in trouble
state
• The NAC charge pump voltage is below
30V, preventing the NACs from operating
• The power supply is defective
Amplifier Overcurrent ACHS • A short is detected on the circuit
•
The speaker wattage tap setting exceeds the
output rating of the amplifier
Primary Audio Output DC ACHS • There is an open DC NAC circuit, or missi
or wrong value EOL resistor
• A short is detected on the a DC NAC circuit
Rail Over Current Trouble PS10-4B The power supply detected an over current
condition (> 10A)
Battery Charger Trouble PS10-4B The charger may not be able to charge the
batteries
Primary Audio Output Analog ACHS • There is an open Audio NAC circuit, or
missing or wrong value EOL resistor
• A short is detected on the Audio NAC circuit
• The output voltage jumper is set wrong
Application Fault PS10-4B The power
supply detected a fault while testing its
internal subsystems
Backup Audio Output Analog ACHS • There is an open audio NAC circuit, or
missing or wrong value EOL resistor
• A short is detected on the Audio NAC circuit
• The output voltage jumper is incorrectly set
Amplifier Daughter Board ACHS The board is defective
Thermistor Supervision PS10-4B The thermistor is either missing or not functioning
Fuse Supervision ACHS There is an open fuse on the amplifier
Measurement Trouble PS10-4B The A/D readings are not reliable
PAL Supervision ACHS The PAL chip on the amplifier is bad
NAC Class A Mismatch PS10-4B •
The expected Class A configuration does not
match actual hardware
• The CLA-PS10 adapter is missing
Riser Supervision FTCU A short or open is detected on the telephone riser
User Interface FTCU A board fault is detected
Master Phone Supervision FTCU A short or open occurred on the phone handset