High-Power Radios - Motorola ASTRO SPECTRA Service Manual

8-12
7. Carefully lift the command board from the housing, making sure that the floating header is
with the RF board.
8. To reassemble the command board, apply a thin coat of thermal compound (for example,
Motorola part no. 11-83166A01) to the audio amplifier mounting surface.
NOTE: Do not use a thick coating of compound as it could degrade the thermal efficiency
9. Install the new command board, and clip the power devices to the chassis, being sure that the
insulator is in place behind the devices.
10. Install new mounting screws (torque 8-10 in.-lbs.), starting with the screw holding down the
audio amplifier. Ensure the screws are aligned with the holes.
11. Connect the VOCON board and option board.
12. Install the VOCON board shield.
13. Reconnect the two connectors.
14. Install the PA assembly, control head, and radio covers.

8.2.7.2 High-Power Radios

1. Use a Torx T15 driver to remove the two screws. Remove the top cover.
2. Disconnect and remove the 12-connector ribbon cable from the command board and the PA
board.
3. Disconnect the 38-conductor ribbon cable from the command board.
4. Remove the heatsink clip from the three transistors in the corner of the board.
5. Remove the VOCON board shield.
6. Remove the VOCON board from the command board after reading the NOTES and
CAUTIONS in the VOCON board section.
7. Use a Torx T15 driver to remove the six screws retaining the command board.
8. Gently work the command board out of the chassis cavity and then remove the foam piece
from the crystal near the PA ribbon connector.
9. To reassemble the command board, apply a thin coat of thermal compound (for example,
Motorola Part No. 11-83166A01) to the audio amplifier mounting surface.
NOTE: Do not use a thick coating of compound as it could degrade the thermal efficiency
10. Install the new command board into the chassis cavity.
11. Replace the foam piece.
12. Using six new screws, start all the screws, and then torque them to 8-10 in.-lbs. Ensure the
screws are aligned with the holes.
13. Replace the heatsink.
14. Connect the 12-connector ribbon cable from the command board to the PA board.
15. Connect the 38-conductor ribbon cable to the command board.
16. Reassemble the VOCON board.
February 3, 2003
Disassembly/Reassembly Procedures: Replacement Procedures
of the heatsink.
Prior to installing the command board, make sure the male-to-male command board
header is fully seated in the RF board.
of the heatsink. Prior to installing the command board, make sure the male-to-male
command board header is fully seated in the RF board.
6881076C20-E