Motorola ASTRO SPECTRA Service Manual

6881076C20-E February 3, 2003
Disassembly/Reassembly Procedures: Replacement Procedures 8-15
8.2.9.2 High-Power Radio
1. Turn the radio topside down and remove the four bottom-cover screws, and remove the
bottom cover.
2. Remove the power amplifier and RF board shields.
3. Remove the six VCO board shield screws and remove the VCO board shield.
4. Gently pry up on the VCO board, where it extends over the RF board, until the VCO board is
disconnected from the RF board.
5. Disconnect the two coaxial cables that plug into the VCO board and remove the board.
6. Remove the metal VCO gasket from around the VCO board.
7. Place the VCO metal gasket around the new VCO board.
NOTE:Be sure the board and gasket are straight and that the board does not bind as the
screws are tightened, pulling the board down to the cavity ledge. Tighten the screws
evenly to avoid warping the board. It is very important to use proper screw torque
to ensure proper operation in vibration environments. Use only new screws.
8. Reconnect both of the coaxial cables to the VCO board.
9. Place the board into the chassis cavity by aligning the pins on the VCO board with the mating
part on the RF board, and pressing the board firmly into place.
10. Replace the VCO board shield using six new mounting screws, and then torque the screws to
8-10 in.-lbs.
11. Install the power amplifier and RF board shields.
12. Replace the bottom cover, and torque the four bottom-cover screws to 6-8 in.-lbs.
8.2.10 RF Board
8.2.10.1 Low-/Mid-Power Radio
1. See the previous paragraph and remove the VCO board.
2. Remove the control head.
3. Disconnect the RF cable that passes through the chassis to the RF board.
4. Remove the six mounting screws, and then remove the RF board.
5. Install the new RF board, and connect the RF cable through the front of the chassis to the RF
board.
6. Install six new mounting screws in the RF board, but wait to tighten them until after you install
the VCO board. Ensure the screws are aligned with the holes.
NOTE:Make sure the male-to-male command board header is fully seated in the command
board before installing the RF board.
7. Install the VCO board.
8. Tighten the new RF and VCO board mounting screws (torque to 8-10 in.-lbs.). Ensure the
screws are aligned with the holes.
NOTE:It is very important to use proper screw torque on both boards to ensure proper
operation in vibration environments.
9. Install the control head and radio covers.

Motorola ASTRO SPECTRA Specifications

General

Frequency Range	136-174 MHz, 403-470 MHz
Number of Channels	Up to 255
Channel Spacing	12.5 kHz, 20 kHz, 25 kHz
Modulation	FM
Operating Temperature	-22°F to +140°F (-30°C to +60°C)