9-34
September 27, 2000
68P81093C75-O
7. Finish reassembling the station as described in Steps 8 through
12 of the Backplane subsection of “Module Replacement.”
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 10.
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. Remove the cover plate on the left end of the front of the station
by removing two Torx screws from the front of the plate and
four Phillips screws from the side and bottom edges of the plate.
4. Pull the Station Control Module and Wireline Module until they
disengage from their respective backplane connectors. The
modules need not be completely removed from the chassis.
5. On the back of the chassis, remove the six Phillips screws
holding the backplane in place.
6. Slowly, but firmly, pull the bottom edge of the backplane away
from the chassis. Continue pulling until the 80-pin card edge
connectors dislodge from the Receiver and Exciter modules.
Then pull the backplane down and away from the top panel of
the chassis.
7. Lay the backplane flat behind the station, and remove all the
attached wires.
8. If the dip switches on the new backplane have not been set to
match the PA/Exciter combination of the station, set them now
according to Table 10.
Table 10
Motherboard DIP Switch Settings
Exciter Frequency
Band
PA Model
Switch 1
Switch 2
VHF Range 1
PLD7981
OFF
OFF
VHF Range 2
PLD7981
ON
OFF
UHF Range 1
PLE9367
OFF
ON
UHF Range 2
PLE9369
ON
ON
