Key Telephone / Slt Telephones Dead - Vodavi Starplus DHS Technical Manual

CPU/Power LED
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 current sensing
poly-switch limits excessive current going to each station. If a station cable pair is shorted or a
telephone's DC power supply is damaged, the poly-switch will temporarily open to protect the
KSU 3x8 Module circuitry.
Table 7-2: Key Telephone / SLT Telephones Dead
DIAGNOSTIC
AID
CPU Heartbeat / Shorted Station
Power LED Lit Pair(s)
Key Telephone Bad Key
Telephone
Shorted station
cable
Shorted KSU-MDF
cable
3x8 Module
ribbon cable not
properly aligned
during installation
3x8 Module bad
CPU Module bad
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; remove all cross connect
wiring that run between the 3x8 Module
66 block and the station cable 66 block.
3 Connect one station directly to the 3x8
Module 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 25 pair cable
from the 3x8 Module to the MDF.
Once the 25 pair cable from the 3x8 Module to
the MDF is inspected, repaired or replaced;
connect the known working telephone directly
to the 3x8 Module 66 block station pair.
If the telephone still will not properly power
up, power down the system and inspect the
3x8 Module ribbon cable for properly aligned
installation. If any problem exists here correct
it and power up the system.
If no problems can be found at the ribbon
cable connector, replace the 3x8 Module.
If the problem persists, replace the KSU.
CORRECTIVE ACTION
7-3