TOA Electronics TOAEXES-5OOO Fault in photo coupler PC-504

Sound of the other

party is broken

during call.

Same symptom

remains even

the station

is replaced.

Immediately after

the calling tone,

the line switches

to cancel, busy,

dial tone, etc.

Same symptom

remains even

the station

is replaced.

Becomes normal

if the station

is replaced.

Adjust the volume control of

station speaker if the room

produces reverberation.

(Lower the volume.)

Increase the gain of MIC AMP.

Replace PCB after checking if

MIC unit is not touching its

case.

One of R-Lines is disconnected.

Fault in photo coupler PC-504

LMU.

Fault in MT-547 on LMU or in

the station.

One of the R-Lines is discon-

nected or the station connector

is not connected properly.

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Contents

Main , CPU off ? -61- on HCU li t as Fig. 1 CPU- P54 P56 Before power supply check, confirm the following three 1. Is voltage selector set correctly? 2. Is AC power supplied? 3. Is power switch O N ? Start checking after disconnecting all wiring connected to DC output of the power supply unit. Faulty power transformer. 1. Turn off the privacy switch on all stations in the 1-1 1-2 1-3 1-4 1-5 Page 8-3. FAULT IN SPECIFIC STATION ONLY Find the cause according to the following table if the fault party. lies with a specific station only, not with all stations. be made at privacy Specific Lamp Fault in photo coupler PC-504 the speech test for each station can then take place. The sound volume can be adjusted by the volume on the The Press-To-Talk bar on the station keyboard must be in high noise areas (more than 60dB noise). tone quality, etc.) must be tested with each line in Secretary Transfer: Is transfer made correctly sure that the switch works.