Service manual

Troubleshooting 3-3
Table 3– 1 Power Problems (Continued)
Symptom Possible Cause Indicators
System does
not power
up/main
blowers off
CSB bus problems
- Cable broken/disconnected along path from
STD I/O
CSB ID module CSB module
- Vaux problem
Message on
console
regarding lost
connections
See above
System does
not power
up/main
blowers off
OCP problems
- OCP present signal not seen by SCM (signal
cable path from STD I/O
STD I/O cable
interface
OCP) (SCM thinks it’s a slave on
the CSB and cannot issue power-up cmds.)
- 48V problem
SCM states
it’s a slave on
the console
OCP LEDs off
System or
part of
system does
not power
up and/or
main
blowers off
48V power problems (may affect part or
entire system)
- Any Vaux problem will cause 48V problems
- Any CSB problem
- Any OCP problem
- Signal from PSM to power distribution
panel on subrack not good (cable connections)
- PSM failure
- PSM service switch in Service position
See above
See above
See above
Power supply
LEDs off
Same
Switch
serv./ PSM
qbb_dc_good
LED
off/console
message
Continued on next page