3M 478DA, D-15 User Manual
Troubleshooting Guide
Model 478DA (D-15)
Single Intercom System
Introduction
The Model 478DA is a single-channel intercomsystem that is used for point-to-point communication applications.
The system includes a visible/audible presence alert and the capability of multiple units communicating with the same
loudspeaker.
Problem Isolation Procedure
Use the troubleshooting table on the following pages to help isolate the problem:
1. Start at the top of the table a nd work down to the bottom.
2. For each symptom listed, determine if it applies to the situation.
3. If a symptom does apply, check (ü) the box adjacent to the symptom.
4. Read across the table to the possible causes and corrections listed in the middle and right columns.
5. Investigate these possible causes and implement the corrections. Possible causes are listed in the order in which
they are most likely to occur.
If none of the possible causes and corrections applies to the situation, call 3M Media InTouch and review the
"checked" symptoms with the t echnical support staff.
1
Technician Troubleshooting Guide Model 478 (D-15)
Figure 1. Operating Controls
Key Control Name Function
1 Power Switch Controls application of power to the system.
Power Indicator Light Indicates power is applied to the system.
2 Volume Control
3 Standby Touch Switch Silences intercom audio to eliminate pickup of undesired
4 Touch/Talk Switch Controls talk/listen communications. Operator touches switch
5 Indicator Lights Red indicates TALK mode.
Adjusts the internal speaker (listen) audio level.
background noise and reconnects optional music/message
source to the external speaker when unit is not in use. The
system automatically exits the standby mode with vehicle
detection or when the Touch/Talk switch is pressed.
to talk and cancel alert tone. Operator releases switch to
listen.
Green indicates LISTEN mode.
Yellow indicates vehicle presence.
Yellow light above STANDBY lights and all other lights are
extinguished when the system is placed in the standby mode.
2
Model 478 (D-15) TechnicianTroubleshooting Guide
Troubleshooting Table
Problem Possible Cause Correction
No inbound audio. Power
Indicator Light (green) is
OFF.
No inbound audio:
• Power Indicator Light
(green) is ON.
• LISTEN Indicator Light
(green) is OFF.
No inbound audio:
• Power Indicator Light
(green) is ON.
No AC power to the unit. Check power supply
transformer or wall outlet.
Defective analog board. Check and replace analog
board.
Defective logic board or
touch pad.
Defective menu speaker,
menu mic, or wiring.
Check and replace logic
board or touch pad.
Check and replace menu
speaker, menu mic, or wiring.
• LISTEN Indicator Light
(green) is ON.
Defective analog board. Check and replace analog
Inbound audio distorted. Defective menu speaker,
menu mic, or wiring.
Defective analog board. Check and replace analog
No outbound audio. Power
Indicator Light (green) is
OFF.
No outbound audio:
• Power Indicator Light
(green) is ON.
• TALK Indicator Light
(red) is OFF when TALK
SWITCH is pressed.
No AC power to the unit. Check power supply
Defective analog board. Check and replace analog
Defective logic board or
touch pad.
board.
Check and replace menu
speaker, menu mic, or wiring.
board.
transformer or wall outlet.
board.
Check and replace logic
board or touch pad.
(continued)
3
Technician Troubleshooting Guide Model 478 (D-15)
Problem Possible Cause Correction
No outbound audio:
• Power Indicator Light
Defective menu speaker,
menu mic, or wiring.
Check and replace menu
speaker, menu mic, or wiring.
(green) is ON.
• TALK Indicator Light
(red) is ON when TALK
SWITCH is pressed.
Defective analog board. Check and replace analog
board.
With car on loop, VEHICLE
Indicator Light (yellow) is
ON, but vehicle detection tone
Alert volume control setting
too low.
Check and/or increase the
Alert volume control setting
on bottom of unit.
does not sound.
Defective analog board. Check and replace analog
board.
With car on loop, VEHICLE
Indicator Light (yellow) is
Defective logic or analog
board.
Check and replace logic or
analog board.
OFF, and vehicle detection
tone does not sound.
Outbound audio distorted. Defective analog board. Check and replace analog
board.
Defective internal
Replace microphone.
microphone.
Defective menu sign
Replace menu sign speaker.
speaker.
3M Media InTouch
3M Center, Building 551-1E-02
St. Paul, MN 55144-1000
Printed on 50% recycled paper,
including 10% post-consumer waste.
Printed in U.S.A.
© 3M 1997 January
78-6912-0660-7 Rev. A
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