Troubleshooting Guide
Model 478DA (D-15)
Single Intercom System
The Model 478DA is a single-channel intercom system 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.
Use the troubleshooting table on the following pages to help isolate the problem:
1.Start at the top of the table and 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 technical support staff.
1
Technician Troubleshooting Guide |
Model 478 (D-15) |
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Figure 1. Operating Controls |
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Key |
Control Name |
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Function |
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1 |
Power Switch |
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Controls application of power to the system. |
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Power Indicator Light |
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Indicates power is applied to the system. |
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2 |
Volume Control |
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Adjusts the internal speaker (listen) audio level. |
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3 |
Standby Touch Switch |
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Silences intercom audio to eliminate pickup of undesired |
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background noise and reconnects optional music/message |
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source to the external speaker when unit is not in use. The |
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system automatically exits the standby mode with vehicle |
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detection or when the Touch/Talk switch is pressed. |
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4 |
Touch/Talk Switch |
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Controls talk/listen communications. Operator touches switch |
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to talk and cancel alert tone. Operator releases switch to |
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listen. |
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5 |
Indicator Lights |
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Red indicates TALK mode. |
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Green indicates LISTEN mode. |
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Yellow indicates vehicle presence. |
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Yellow light above STANDBY lights and all other lights are |
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extinguished when the system is placed in the standby mode. |
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2
Model 478 (D-15) Technician Troubleshooting Guide
Troubleshooting Table
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Problem |
Possible Cause |
Correction |
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No inbound audio. Power |
No AC power to the unit. |
Check power supply |
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Indicator Light (green) is |
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transformer or wall outlet. |
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OFF. |
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Defective analog board. |
Check and replace analog |
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board. |
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No inbound audio: |
Defective logic board or |
Check and replace logic |
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∙ |
Power Indicator Light |
touch pad. |
board or touch pad. |
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(green) is ON. |
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∙ |
LISTEN Indicator Light |
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(green) is OFF. |
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No inbound audio: |
Defective menu speaker, |
Check and replace menu |
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∙ |
Power Indicator Light |
menu mic, or wiring. |
speaker, menu mic, or wiring. |
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(green) is ON. |
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∙ |
LISTEN Indicator Light |
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(green) is ON. |
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Defective analog board. |
Check and replace analog |
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board. |
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Inbound audio distorted. |
Defective menu speaker, |
Check and replace menu |
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menu mic, or wiring. |
speaker, menu mic, or wiring. |
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Defective analog board. |
Check and replace analog |
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board. |
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No outbound audio. Power |
No AC power to the unit. |
Check power supply |
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Indicator Light (green) is |
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transformer or wall outlet. |
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OFF. |
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Defective analog board. |
Check and replace analog |
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board. |
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No outbound audio: |
Defective logic board or |
Check and replace logic |
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∙ |
Power Indicator Light |
touch pad. |
board or touch pad. |
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(green) is ON. |
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∙ |
TALK Indicator Light |
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(red) is OFF when TALK |
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SWITCH is pressed. |
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(continued)
3
Technician Troubleshooting Guide |
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Model 478 (D-15) |
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Problem |
Possible Cause |
Correction |
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No outbound audio: |
Defective menu speaker, |
Check and replace menu |
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∙ |
Power Indicator Light |
menu mic, or wiring. |
speaker, menu mic, or wiring. |
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(green) is ON. |
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∙ |
TALK Indicator Light |
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(red) is ON when TALK |
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SWITCH is pressed. |
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Defective analog board. |
Check and replace analog |
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board. |
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With car on loop, VEHICLE |
Alert volume control setting |
Check and/or increase the |
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Indicator Light (yellow) is |
too low. |
Alert volume control setting |
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ON, but vehicle detection tone |
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on bottom of unit. |
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does not sound. |
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Defective analog board. |
Check and replace analog |
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board. |
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With car on loop, VEHICLE |
Defective logic or analog |
Check and replace logic or |
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Indicator Light (yellow) is |
board. |
analog board. |
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OFF, and vehicle detection |
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tone does not sound. |
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Outbound audio distorted. |
Defective analog board. |
Check and replace analog |
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board. |
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Defective internal |
Replace microphone. |
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microphone. |
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Defective menu sign |
Replace menu sign speaker. |
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speaker. |
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3M Media InTouch
3M Center, Building 551-1E-02
St. Paul, MN 55144-1000
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