Thales DVOR 432, Техническое руководство, Страница: 167 / 234

DVOR 432
Operation and Maintenance Repairs
6-17
Ed. 01.04
6.2.3 Replacing Subassemblies
WARNING
The heat sinks of the modulators (MOD-110P) and of the carrier amplifier (CA-100C)
may warm up during operation. This is normal and does not affect the function. When reĆ
placing these subassemblies it is recommended to let them cool down for a while or take
suitable measures (e.g. gloves). When replacing the subassemblies SYN und CCP avoid
touching the heat sinks of the MOD-110P.
6.2.3.1 Disconnecting the Voltage before replacing Subassemblies
CAUTION
The voltage must always be disconnected before removing or installing subassemblies
(subject to only a very few exceptions). It is sufficient to switch off all the transmitter subasĆ
semblies, the DCC-MV and the DCC-28 with either of switches TX1 or TX2 on the PMM
subassembly. The transmitter subassemblies can also be switched off by means of a PC
command.
Before replacing an ACC-module the BCPS must always be disconnected from the
mains.
If a monitor subassembly is affected (MSP-VD), the associated DCC subassemblies
must be removed. It is not necessary to switch them off beforehand with both TX1 and
TX2 on the PMM.
If the CSL must be changed, both TX1 and TX2 must be switched off beforehand.
The VAM, MODEM and the DCC-3-05 subassemblies may be removed and installed
when live. The special design of their contacts prevents damage from occurring.
6.2.3.2 Subassemblies in the Transmitter Rack and Power Supply
The table below lists the work which may be necessary after a subassembly has been replaced.
Please also refer to Sections 6.2.1.1 and 6.2.1.1.3 .
a) The relevant transmitter must be de-energized before removing or installing subassemblies, prefĆ
erably by switching it off on the PMM subassembly. It should be noted that the following subassemĆ
blies are only de-energized if both switches and switch NAV (for CSL) on the PMM are switched
off:
LCP
DCC-3-05
CSL
MSP-VD
VAM
ASU complete (DVOR only)
b) Several of the subassemblies have DIP-FIX switches or jumpers on their pc boards. It is essential
to check that the switches or jumpers on the new subassemblies are set to the same positions as
on the old subassemblies. Section 6.2.4 contains a list of the DIP-FIX switches and jumpers.
c) Check that all the RF cables have been connected correctly before switching the transmitter on
again, and make sure that either the antenna or a dummy load is connected to the transmitter
output signals (CSB, SB1, SB2).
d) All subassemblies in the assembly carrier have plug-in RF connections.