TB8100 Service Manual Power Amplifier Board Replacement 193
© Tait Electronics Limited September 2006
10.9 Replacing the Boost Regulator Board in a 12V PA
Refer to “Power Amplifier Disassembly and Reassembly” on page 173 for
details on removing and refitting the cover, and for screw torque settings.
The circled numbers in the following instructions refer to Figure 10.8 on
page 194.
Removal 1. Remove the cover.
2. Disconnect the 12VDC
b and 28VDC c output cables from their
sockets on the boost regulator board.
3. Remove the M3 Torx screws securing Q3
d and D1 e to the
heatsink.
4. Remove the M3 Torx screws securing the board to the heatsink and
spacers. Note that the two screws
f in the DC input filter
compartment are longer than the other screws.
5. Carefully lift the board off the spacers and heatsink.
Refitting the
Original Board
1. If you are refitting the original board, follow the removal instructions
in reverse order.
2. If necessary, check the board is working correctly (refer to “Boost
Regulator Board (12V PA Only)” on page 168).
3. Refit the cover.
Refitting a New
Board
Replacement boost regulator boards are supplied as two separate assemblies:
the main boost regulator board
g, and the DC input filter board h. You
must mount both boards to the heatsink before soldering them together.
1. Position the main board on the spacers. Align the mounting holes for
Q3, D1, and the board itself, then fit the M3 Torx screws. Tighten
the screws to the correct torque.
2. Position the DC input filter board on the heatsink and secure with
the M3 Torx screws. Ensure the legs of the two feedthrough
capacitors
i are correctly positioned in the slots on the main board.
Tighten the screws to the correct torque.
3. Solder the legs of the two feedthrough capacitors to the main board.
4. Fit the solder tag under the M3 Torx screw labelled
j as shown.
Tighten the screw to the correct torque and solder the tag to the
shield
1).
5. Reconnect the 12VDC and 28VDC output cables.
6. If necessary, check the board is working correctly (refer to “Boost
Regulator Board (12V PA Only)” on page 168).
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