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 GuideModel 478 (D-15)
Figure 1. Operating Controls
KeyControl NameFunction
1Power SwitchControls application of power to the system.
Power Indicator LightIndicates power is applied to the system.
2Volume Control
3Standby Touch SwitchSilences intercom audio to eliminate pickup of undesired
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
ProblemPossible CauseCorrection
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 GuideModel 478 (D-15)
ProblemPossible CauseCorrection
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.
The Model 481 is a 6-channel intercom system that is typically used to provide communication between store
counters and pump islands in self-service gas stations, convenience stores and truck stops.
Intracom D-20
3
OFF ON
VOLUME
SP-206A
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.
1Power SwitchProvides power to mainstation.
2Power Indicator LightIndicates power is on and the system is ready to operate.
3Volume ControlAdjusts INCOMING audio level.
NOTE: Volume level adjustments for alert tone and outside
speakers are set by the installer.
4Channel Selector Switches (1-6)These switches control talk/listen communication for
numbered channels. Operator touches switch to talk and
releases switch to listen.
5Indicator LightsRed indicates TALK mode.
Green indicates LISTEN mode.
Yellow (steady) indicates channel on "HOLD."
Yellow (flashing) indicates incoming call WAITING.
SP-205A
6Hold SwitchPlaces selected channel in "HOLD" mode.
7All Call SwitchControls conversation with all channels simultaneously.
8Standby SwitchSilences incoming audio to eliminate undesired background
noise pickup when unit is not in use. Touching any
CHANNEL SELECTOR SWITCH releases STANDBY
mode.
9Standby Indicator LightIndicates unit is in STANDBY mode.
2
Model 481BA (D-20)TechnicianTroubleshooting Guide
Troubleshooting Table
ProblemPossible CauseCorrection
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.
•LISTEN Indicator Light
(green) is ON.
No AC power to the unit.Check power supply
transformer or wall outlet.
Defective logic board or
touch pad.
Defective speaker/mic or
analog board.
Check and replace logic
board or touch pad.
Check and replace speaker or
analog board.
Inbound audio distorted.Defective speaker/mic or
analog board.
No outbound audio:
•Power Indicator Light
(green) is ON.
•TALK Indicator Light
(red) is OFF when TALK
SWITCH is pressed.
No outbound audio:
•Power Indicator Light
(green) is ON.
•TALK Indicator Light
(red) is ON when TALK
SWITCH is pressed.
The VEHICLE Indicator
Light (yellow) blinks, but
vehicle detection tone does
not sound.
The Model 479 is a 2-channel intercom system that is typically used to provide communication between store
counters and pump islands in self-service gas stations, convenience stores and truck stops.
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 GuideModel 479 (D-30)
6
5
3
5
1
2
4
SP-208A
Figure 1. Operating Controls
KeyControl NameFunction
1Power SwitchControls application of power to the system.
Power Indicator LightIndicates power is applied to the system.
2Volume Control
3Talk Switches (A & B)Control talk/listen communication for the respective channel
4Standby SwitchSilences audio to eliminate pickup of undesired background
Adjusts the mainstation internal speaker (listen) audio level.
(A or B). Operator touches switch to talk and releases switch
to listen.
noise when unit is not in use. Touching either the Channel A
or Channel B Talk Switch releases STANDBY mode.
Vehicle Detection automatically places the system into the
Channel A listen mode.
5Indicator Lights (same for Channel A and
Channel B)
6Standby Mode SwitchAUTO (automatic) position causes system to switch from
Red indicates TALK mode.
Green indicates LISTEN mode.
Yellow indicates vehicle presence (when used with 3M
SODAR or magnetic loop detection system).
All indicator lights are extinguished when mainstation is in
the standby mode.
Channel A Listen to Standby when there is no vehicle detect
signal. MAN (manual) position allows operator to use
Channel A without vehicle detection.
2
Model 479 (D-30)TechnicianTroubleshooting Guide
Troubleshooting Table
ProblemPossible CauseCorrection
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 GuideModel 479 (D-30)
ProblemPossible CauseCorrection
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
Vehicle Detect-to-Main
signal too low.
Adjust R6 to increase signal
level.
ON, but vehicle detection tone
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.
Food Services Trade Department
3M Center, Building 551-1E-02
St. Paul, MN 55144-1000
Printed on 50% recycled paper,
including 10% post-consumer waste.