1
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 systemincludes 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 pagesto help isolate the problem:
1. Start at the top of the table and work down to the bottom.
2. For each symptomlisted, determine if it applies to the situation.
3. If a symptomdoes 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 rightcolumns.
5. Investigatethese 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 InTouchand review the
"checked" symptomswith the technical support staff.