Low-/Mid-Power Radio; Vco Board - Motorola ASTRO SPECTRA Service Manual

8-14
9. Carefully remove the front-end receiver board from the radio chassis cavity and disconnect
the coaxial cable beneath it.
NOTE: Be careful to insert the Rx injection coaxial cable straight into the receptacle on the
10. Install the new front-end receiver board into the radio chassis cavity.
11. Reconnect the coaxial cable beneath the front-end board.
12. Feed the coaxial cables through the chassis into the opposite side.
13. Using four new screws and a Torx T15 driver, install the receiver front-end shield, and then
torque the screws to 8-10 in.-lbs. Ensure the screws are aligned with the holes.
14. Replace the radio top cover, and torque the two top-cover screws to 6-8 in.-lbs.
15. Turn the radio topside down and reconnect the coaxial cable into the power amplifier board
and RF board receptacles.
16. Replace the power amplifier shield, RF board shield, and bottom cover.
17. Torque the four bottom-cover screws to 6-8 in.-lbs.
NOTE: No alignment is necessary.
8.2.9

VCO Board

8.2.9.1 Low-/Mid-Power Radio

1. Remove the radio bottom cover.
2. Remove the PA assembly and disconnect the TX injection coax that passes through the
chassis to the VCO board.
3. Remove the RF board cover.
4. Remove the six mounting screws and the cover.
5. Carefully lift the board far enough to expose the Rx injection coaxial cable underneath, which
runs from a receptacle on the VCO through a hole in the chassis to the receiver front end
assembly.
6. Unplug the coaxial cable from the receptacle on the VCO board, and then lift straight up on
the VCO board to remove it from the chassis.
7. To install the new board, plug in the Rx injection coaxial cable (from the receiver front end)
into the receptacle near the outer edge of the board.
8. Align the opposite edge connector with the RF board connector and snap it into place.
NOTE: Be sure the board and gasket are straight and that the board does not bind as the
9. Connect the PA board's RF cable to the VCO board connector (through the chassis).
10. Using six new mounting screws, install the VCO cover, and then torque the screws to 8-10
in.-lbs. Ensure the screws are aligned with the holes.
11. Install the PA assembly and the radio cover.
February 3, 2003
Disassembly/Reassembly Procedures: Replacement Procedures
VCO board, and be sure it is fully inserted.
Also, be careful to not bend the tip of the coaxial cable, which provides the contact
for the connection. Make sure all connections are tight, and that all shields are
pressed firmly into their proper cavities.
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.
6881076C20-E