User's Manual

SBS-900 Shore Based Radar Systems
Chapter 10: Corrective maintenance
KH-1602-2 issue 1: Standard SBS900 Systems Operator & Maintenance Handbook
Page 147 of 240
10.7.6 Power unit assembly
AC-DC power supply unit
Part number SBS-A146
The AC-DC power supply unit is a single assembly that provides the DC
outputs required by the transceiver enclosure.
The PSU assembly consists of a mains rectification unit and a number of DC/
DC converters mounted onto a chassis.
WARNING: Lethal AC and DC voltages of up to 450VDC are present within the SBS-
A146 assembly. Ensure the system is fully isolated prior to disconnecting the unit.
AC supplies: Prior to carrying out any maintenance, the system must be fully isolated
and disconnected from all single and 3-phase AC supplies. See system isolation in the
planned maintenance section of the system handbook.
UPS (Uninterruptable Power Supply): Where connected, ensure that UPS supplies to
the RDU are fully isolated prior to carrying out any maintenance task on the system.
Location: Depending on the system there will be one or two power units in the chassis.
Single transceiver systems: One PSU located in the left hand side of the
enclosure.
Dual transceiver systems: Two power supplies one on the left and another
on the right hand side of the enclosure.
10.7.6.1 Spares & repairs
The repair of the SBS-A146 is limited to unit replacement only.
- The power supply assembly contains no field serviceable or user adjustable parts.
- The unit must NOT be dismantled in the field as specialist equipment is required for testing the
electrical safety barriers.
- Circuit diagrams and sub assembly spares for the power unit assembly are not available.
10.7.6.2 Output checks
With the system switched ON, the voltages for the Transceiver Enclosure power supply can
be check using the menus on the RDU.
From the RDU front panel select Status then Enclosure. In the Enclosure menu, the
following power supply rails can be checked:
PSU A PSU B Internal supplies
PSU Tx A 3.3V PSU Tx A 3.3V PSU INT +15V
PSU Tx A 15V PSU Tx A 15V PSU INT +5.0V
PSU Tx A 13V PSU Tx A 13V