AT&T System 25 - Manual (Page 279)

MAINTENANCE
Multiple Troubles or Trouble That Cannot Be Diagnosed
Symptoms:
Red LED is lighted on all port CPs. SAT displays this message:
“FAIL:
C P U : A R C H ANGEL INSANE: CHECK ZTN85:
TERMINATOR?”.
P r o c e d u r e s :
1.
2.
3.
4.
5.
Check that the TDM bus terminator card(s) is installed in the rear pin
f i e l d ( s ) .
Note: The CPU/Memory CP provides built-in b u s
termination circuitry for one end of the bus, and the
TDM bus termination card is used to terminate the
other end.
Reseat the CPU/Memory and Service CPs (see “Reseating and
Replacing Circuit Packs” under “Routine Maintenance” in this
section).
If troubles persist, replace units in this order: TDM bus terminator
card; Service Circuit CP; CPU/Memory CP. Recheck the system
after each unit has been replaced to see if the trouble is clear.
If troubles still persist, check the intercabinet cabling.
If troubles cannot be cleared, escalate to higher level maintenance.
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