Receiver Front-End Board - Motorola ASTRO SPECTRA Service Manual

Disassembly/Reassembly Procedures: Replacement Procedures
17. Replace the section VOCON board shield and the top cover, and then torque the screws to 6-
8 in.-lbs.
8.2.8

Receiver Front-End Board

8.2.8.1 Low-/Mid-Power Radio
1. Remove the radio top cover.
2. Remove the two mounting screws and unplug the control head.
3. Remove the EMI metallic shielding tape (Motorola Part No.11-85984D01).
Be careful to prevent any tape particles from falling inside the chassis.
4. Disconnect the coaxial cable that passes through the front of the chassis from the RF board.
5. Remove the PA assembly.
6. Disconnect the coaxial cable that passes through the rear of the chassis to the receiver front
end.
7. Remove the four screws and front-end cover, and carefully lift the receiver front-end board
from the chassis.
NOTE: Be careful to insert the Rx injection coaxial cable straight into the receptacle on the
8. Install the new assembly, being careful not to damage the RF connection that passes through
the chassis to the VCO.
9. Reconnect both coaxial cables.
10. Clean the chassis surface with isopropyl alcohol, and place a new piece of EMI metallic
shielding tape (Motorola Part No. 11-85984D01) over the coaxial cable passing through the
front of the chassis.
NOTE: The EMI metallic shielding tape must cover the hole in the receiver front-end board.
11. Install the front end cover and four mounting screws.
12. Install the PA assembly, control head, and radio cover.
NOTE: No alignment is necessary.
8.2.8.2 High-Power Radio
1. Turn the radio top side down and use a Torx T15 driver to remove the four bottom-cover
screws.
2. Remove the bottom cover.
3. Remove the power amplifier and RF board shields.
4. Disconnect the RX coaxial cable that comes through the power amplifier board.
5. Disconnect the coaxial cable from the RF board.
6. Feed both cables back to the top side of the radio.
7. Using a Torx T15 driver, remove the two top cover screws, and then remove the radio top
cover.
8. Using a Torx T15 driver remove the four screws to the receiver front-end shield, and then
remove the shield.
6881076C20-E
VCO board, and be sure it is fully inserted. Be careful not to bend the tip of the
coaxial cable, which provides the contact for the connection.
This same piece of tape must also cover at least half of the coaxial cable.
8-13
February 3, 2003