Circuit Pack Descriptions
Issue 8.0 July 2002
7-49
Power Circuitry 7
The STS1E circuit pack receives two sources of −48 volts that are diode OR'd,
fused, and filtered. A modular DC-to-DC power converter produces +5 volts used
on the circuit pack. The LSSW circuit packs supply power to the input and output
protection relays on the STS1E circuit packs.
If the STS1E circuit pack detects a failure of the onboard fuse or power converter,
the red FAULT LED will light. If the fuse or power converter fails, the LNCTL circuit
pack provides +5 volts to light the FAULT LED on the STS1E circuit pack.