TB8100 Service Manual Power Amplifier Board Replacement 193© Tait Electronics Limited September 200610.9 Replacing the Boost Regulator Board in a 12V PARefer to “Power Amplifier Disassembly and Reassembly” on page 173 fordetails on removing and refitting the cover, and for screw torque settings.The circled numbers in the following instructions refer to Figure 10.8 onpage 194.Removal 1. Remove the cover.2. Disconnect the 12VDC b and 28VDC c output cables from theirsockets on the boost regulator board.3. Remove the M3 Torx screws securing Q3 d and D1 e to theheatsink.4. Remove the M3 Torx screws securing the board to the heatsink andspacers. Note that the two screws f in the DC input filtercompartment are longer than the other screws.5. Carefully lift the board off the spacers and heatsink.Refitting theOriginal Board 1. If you are refitting the original board, follow the removal instructionsin reverse order.2. If necessary, check the board is working correctly (refer to “BoostRegulator Board (12V PA Only)” on page 168).3. Refit the cover.Refitting a NewBoard Replacement boost regulator boards are supplied as two separate assemblies:the main boost regulator board g, and the DC input filter board h. Youmust mount both boards to the heatsink before soldering them together.1. Position the main board on the spacers. Align the mounting holes forQ3, D1, and the board itself, then fit the M3 Torx screws. Tightenthe screws to the correct torque.2. Position the DC input filter board on the heatsink and secure withthe M3 Torx screws. Ensure the legs of the two feedthroughcapacitors 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 theshield 1).5. Reconnect the 12VDC and 28VDC output cables.6. If necessary, check the board is working correctly (refer to “BoostRegulator Board (12V PA Only)” on page 168).
