Exciter; Frequency Band Considerations; Physical Replacement Of The Exciter Module; After Installing The New Exciter Module - Motorola PDR 3500 Basic Service Manual

Exciter

Frequency Band
Considerations
Physical Replacement of
the Exciter Module
After Installing the New
Exciter Module
68P81093C75-O
When replacing the Exciter Module, it is important to remember the
frequency-sensitive nature of the Exciter/Power Amplifier
combination. The Exciter and the PA must match according to the
model breakdown table in this manual. If an Exciter with a new
frequency band is being installed, the corresponding PA must be
installed, as described in the Power Amplifier subsection of "Module
Replacement."
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. Disconnect the coaxial cable running to a mini-UHF connector
at the front of the Exciter.
4. 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. Slide the mounting plate out of the front of the
chassis.
5. Pull out the old Exciter Module by gripping behind the mini-
UHF connector and pulling gently.
6. Insert the new module. Make sure it is flat on the bottom of the
chassis. Push it firmly into the chassis until it seats into the card-
edge connectors on the backplane. (Do not slam the board
against the backplane or push any harder than necessary to seat
the connectors.)
7. If desired, power up the station while it is still out of the case to
make sure the module is securely in place. If the LEDs do not
light, are dim, or flash rapidly, one or more modules are not
seated properly. Unplug the station before continuing to the
next step.
8. Reassemble the station by reversing Steps 2 through 4.
Perform the following alignment procedures as described in the RSS
User's Guide (part number 68P81085E35):
• Tx Deviation Gain Adjust
• Reference Modulation
For ASTRO Simulcast systems only:
• ASTRO/Simulcast Launch Time Offset
September 27, 2000 9-31