User's Manual

68P81093C75-A 9-35
Backplane
Before Installing the New
Backplane
The PDR 3500 motherboard contains circuitry which translates
between the Exciter from the original Quantar and the PA from the
Spectra™ mobile radio. Since the translations depend upon the
frequency band of the Exciter and the PA, this circuitry is also
frequency-sensitive. For the proper translation path to be selected,
the DIP switches located on the motherboard must be set based on
the frequency band of the station.
Before installing the new Backplane, set its DIP switches according
to Table 12.
Physical Replacement of
the Backplane
1. Turn off the station’s power by unplugging the AC and DC
power cords from the top panel.
2. Remove the eight Phillips screws from the edges of the station’s
top panel and lift the chassis out of the case.
3. Tilt the chassis up on its back edge; then, from the bottom of the
chassis, remove the six Phillips screws holding the Exciter’s
mounting plate.
4. Remove the cover plate on the left end of the front of the station
by removing two screws from the front of the plate, then
removing the four Phillips screws from the side and bottom
edges of the plate. For VHF and UHF stations, also remove the
two screws under the Receiver’s preselector.
5. Pull the Station Control Module and Wireline Module (if
applicable) away from the backplane until they disengage from
their backplane connectors (approximately 1/2"). The modules
need not be completely removed from the chassis.
6. For non-800 MHz stations, a coaxial cable runs from the
receiver’s preselector through the center wall of the chassis.
Disconnect the cable from the preselector and push the loose
end of the cable through the center wall so that it is clear of the
receiver.
Table 12. Motherboard DIP Switch Settings
Station
Model
Exciter
Band
PA Model Switch 1 Switch 2 Switch 3 Switch 4
P2066 VHF R1 PLD7981 OFF OFF OFF OFF
P2067 VHF R2 PLD7981 ON OFF OFF OFF
P2068 UHF R1 PLE9367 OFF ON OFF OFF
P2069 UHF R2 PLE9380 ON ON OFF OFF
P2070/
P2072
UHF R3 PLE9380/
PLE9381
OFF OFF ON OFF
P2071 UHF R4 PLE9381 ON OFF ON ON
P2073 800 MHz PLF7695 OFF ON ON OFF