Specifications

82 MDS 4790/9790 Series I/O Guide MDS 05-3438A01, Rev. E
Invisible place holder
Figure 37. RJ-11 to DB-9 Adapter Cable
8.0 REPLACING ASSEMBLIES
Component-level repair of a transceiver board in the field is not recom-
mended due to the complex nature of the circuitry and the use of sur-
face-mount technology throughout the radio. Malfunctioning
assemblies should be returned to the factory (or authorized service
center) for repair or replacement.
One approach to field-level servicing is to have spare modules available
for the four easily replaced assemblies—the Main Transceiver Board,
Power Supply, Front Panel, and Internal Duplexer. In this way, a defec-
tive assembly can be quickly removed and replaced with a working unit.
The following instructions describe the removal and installation of these
assemblies.
Primary power to the radio must be disconnected before removing or
installing transceiver board or power supply assemblies.
8.1 Transceiver Board and Power Supply
Assemblies
To remove either of these assemblies, loosen the two captive thumb-
screws at each side of the module, and slide the unit straight out as
shown in Figure 38. (There are no cables to disconnect, as the modules
are fitted with in-line connectors.)
To re-install these modules, make sure that the slides are properly
aligned with the guide slots on the chassis, and push straight in. Tighten
the thumbscrews to secure the assembly.
RXD
TXD
GND
2
3
5
DB-9 FEMALE
(TO COMPUTER)
TXD
RXD
GND
4
5
6
RJ-11 PLUG
(TO RADIO)
RJ-11 PIN LAYOUT
1
6
CAUTION
POSSIBLE
EQUIPMENT
DAMAGE