Key Telephone / Slt Telephones Dead - STARPLUS DHS-L Technical Manual

System Diagno sti cs
Symptom
Telephones/station
apparatus dead.
The key telephones use only one twisted cable pair for power, data control and voice
communications.There are no fuses for station interface protection.Instead,a currentsensing
poly-switch limits excessive currentgoing to each station. If a station cable pairis shorted or a
telephone's DC powersupply is damaged, the poly-switch will temporarilyopen to protectthe
Module circuitry.
Table 6-2: Key Telephone / SLT Telephones Dead
Diagnostic Aid
MPB Heartbeat / Shorted Station
LED Lit Pair(s)
Key Telephone Bad Key
Telephone
Shorted station
cable
Shorted KSU-MDF
cable
Chapter 6 - Maintenance /Troubleshooting
Cause
1. At MDF, remove cross connect (jumper)
wires at the punch-down (66M1-50) block
going to all affected stations.
2. Reconnect stations one by one verifying
that each power up correctly.
When one is found that will not power up:
1. Disconnect the telephone at the user
location.
2. Replace with a known working telephone.
If the new station power up is normal,
replace the first connected key telephone.
If the new station also does not power up,
follow the remaining steps for the
individual station.
If none power up; removeall cross connect
wiring that run between the Module 66
block and the station cable 66 block.
3. Connect one station directly to theModule
66 block station pair.
If the key telephone power up is normal:
inspect, repair or replace the station cable.
If the key telephone does not power up:
inspect, repair or replace the cable from the
Module to the MDF.
Once the cable from the Module to the MDF is
inspected, repaired or replaced; connect the
known working telephone directly to the
Module 66 block station pair.
Corrective Action
6-5