S408 REPAIR MANUAL
These instructions are intended to help restore any ailing S408 Passive Loudspeaker back to factory working conditions. They show how to remove and replace the drivers. Please contact Mackie Technical Support (1-800-898-3211) to receive a Service Request Number and Order Number for parts needed for this restoration. They will also help you determine the nature of the problem and what parts will repair the unit.
Top left woofer replacement: 1 8 7 1 2 3 7 8 2 3 9 4 10 5 11 6 12 1 Six screws need to be removed from each side of the front of the grill (twelve screws total) using the phillips head screwdriver. This grill has a tendency to want to “pop” off, so please be sure to hold it in place with one hand or arm while removing the screws with your free hand. In addition to the grill, the screws also hold the decorative trim. The trim should be removed, too. Keep the twelve screws in a safe place.
Top left woofer replacement continued: 3 Carefully begin to remove the woofer. Caution: The woofer is approximately 8 pounds with the weight unevenly distributed. + - 5 push down 4 The positive (blue and black) and negative (solid black) cables are still attached to the woofer terminals. Remove the cables from their terminals simply by pushing down on the terminal and pulling out the cable. * The picture above shows what the S408 looks like with the grill and top left woofer removed.
Top right woofer replacement: 8 7 1 1 2 7 8 2 3 6 5 3 9 4 10 5 11 6 12 1 Six screws need to be removed from each side of the front of the grill (twelve screws total) using the phillips head screwdriver. This grill has a tendency to want to “pop” off, so please be sure to hold it in place with one hand or arm while removing the screws with your free hand. In addition to the grill, the screws also hold the decorative trim. The trim should be removed, too.
Top right woofer replacement continued: 3 Carefully begin to remove the woofer. Caution: The woofer is approximately 8 pounds with the weight unevenly distributed. 5 - + push down 4 The positive (blue and black) and negative (solid black) cables are still attached to the woofer terminals. Remove the cables from their terminals simply by pushing down on the terminal and pulling out the cable. * The picture above shows what the S408 looks like with the grill and top right woofer removed.
Bottom left woofer replacement: 1 7 2 8 3 9 4 10 5 8 11 1 2 7 6 12 3 6 5 1 Six screws need to be removed from each side of the front of the grill (twelve screws total) using the phillips head screwdriver. This grill has a tendency to want to “pop” off, so please be sure to hold it in place with one hand or arm while removing the screws with your free hand. In addition to the grill, the screws also hold the decorative trim. The trim should be removed, too.
Bottom left woofer replacement continued: 3 Carefully begin to remove the woofer. Caution: The woofer is approximately 8 pounds with the weight unevenly distributed. push down 5 4 + The positive (blue and black) and negative (solid black) cables are still attached to the woofer terminals. Remove the cables from their terminals simply by pushing down on the terminal and pulling out the cable. * The picture above shows what the S408 looks like with the grill and bottom left woofer removed.
Bottom right woofer replacement: 1 7 2 8 3 9 4 10 1 5 8 11 2 3 7 6 12 1 Six screws need to be removed from each side of the front of the grill (twelve screws total) using the phillips head screwdriver. This grill has a tendency to want to “pop” off, so please be sure to hold it in place with one hand or arm while removing the screws with your free hand. In addition to the grill, the screws also hold the decorative trim. The trim should be removed, too.
Bottom right woofer replacement continued: 3 Carefully begin to remove the woofer. Caution: The woofer is approximately 8 pounds with the weight unevenly distributed. push down 5 + 4 The positive (blue and black) and negative (solid black) cables are still attached to the woofer terminals. Remove the cables from their terminals simply by pushing down on the terminal and pulling out the cable. * The picture above shows what the S408 looks like with the grill and bottom right woofer removed.
High Frequency Driver replacement: 1 7 2 8 1 2 3 4 3 9 12 5 4 10 11 6 10 5 11 6 12 1 Six screws need to be removed from each side of the front of the grill (twelve screws total) using the phillips head screwdriver. This grill has a tendency to want to “pop” off, so please be sure to hold it in place with one hand or arm while removing the screws with your free hand. In addition to the grill, the screws also hold the decorative trim. The trim should be removed, too.
High Frequency Driver replacement continued: 3 Carefully begin to remove the entire horn assembly (with the high frequency driver still attached). Caution: The horn weighs about 8 pounds, and the weight is unevenly distributed. - 5 Push down + 4 The positive (red and black) and negative (solid black) cables are still attached to the high frequency driver terminals. Remove the cables from their terminals simply by pushing down on the terminal and pulling out the cable.
High Frequency Driver replacement continued: locking washer bolt flat washer 6 7 Four bolts and eight washers may be removed from the driver using the 8mm combination wrench. Turn counterclockwise to loosen and remove, clockwise to tighten. The other three are located around the horn assembly. Notice that the flat washer is on the bottom, followed by the locking washer, and finally the bolt. Keep the four bolts, four locking washers, and four flat washers in a safe place.
Diaphragm replacement: 1 At the present time (January 2007), diaphragms are not currently available, so you will have to replace the complete driver following the previous section (pages 11-13). If you have received a diaphragm, please follow the steps below. 2 Follow steps 1-5 of the high frequency driver replacement instructions, as the horn will need to be removed in order to access the diaphragm. 1 4 2 3 3 The horn assembly is shown above with the high frequency driver circled.
Diaphragm replacement continued: 7 6 This is what the plate adapter and diaphragm look like after they have been removed from the horn assembly. The diaphragm is separated from the plate adapter simply by pushing down on the terminals. This is what the plate adapter (left) and diaphragm (right) both look like. Place the new diaphragm (part # coming soon) where the old one was. Follow the same steps as above, but backwards 6 to 1.
Input assembly replacement: 1 2 8 3 7 4 6 5 1 2 8 3 7 4 6 1 5 Eight screws need to be removed from the input assembly (located on the rear of the cabinet) using the phillips head screwdriver. Once the screws are removed, the input assembly may be loosened by prying a flat head screwdriver in between it and the cabinet. Keep the eight screws in a safe place.
Input assembly replacement continued: J3 + 1 2 Thru J4 Input Pull out J3 J4 + - Thru 2 Once loosened, the input assembly may be easily removed from the cabinet. Do not completely take the input assembly off yet, as two cables need to be removed first. J4 Pull out J3 - + Input Thru 1 2 3 2 1 Input Two cables need to be removed from the input assembly PCB (as shown on the left and above): (1) the solid black cable attaches to the negative terminal (connection J4).
Input assembly replacement continued: 4 Place the new input assembly (part #0012048) where the old one was. Follow the same steps as above, but backwards 3 to 1. Remove the serial number from the faulty input assembly (as shown in the picture above) and place on the new input assembly. Power up the S408 and relish in the fact that you just replaced an input assembly.
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