EM Acoustics EMS-81 compact passive loudspeaker - Manual (Page 19)

19
EMS Series User Manual
www.emacoustics.co.uk
EMS-152: Low Frequency Drive Unit
1. Carefully lift back the foam on the top & bottom edges of the grille. Remove the five
PoziDrive screws (3 top, 2 bottom using a PZ2 screwdriver) and insert a flat-blade
screwdriver under the grille. This can then be used to ease the grille out of its locating slots.
2. Using a 5mm Allen Key, undo the six bolts securing the drive unit in place. The drive unit can then be
lifted out of place by using your finger or a flat blade screwdriver into the recesses in the baffle. Carefully
disconnect the cables from the drive unit.
3. To reinstate the drive unit, simply reverse the above procedure. Please observe correct polarity – red
cable to positive terminal, black to negative. When tightening the six M6 bolts holding the drive unit in
place, it is a good idea to run a sine wave signal through the enclosure to ensure that the drive unit is
evenly tensioned around its circumference. Uneven tension will be apparent by the sound of the voice coil
rubbing.
4. Reinstate the grille by easing into one slot, then gently applying a curve to the grille and easing it into the
other slot. Reinstate the screws and push the foam back into place.
EMS-152: High Frequency Drive Unit
1. Follow the procedure above to remove the grille.
2. Using a 5mm Allen Key, undo the ten bolts securing the waveguide in place. The assembly can then be
lifted out of place. Carefully disconnect the cables from the drive unit as soon as you can reach them to
avoid placing unnecessary strain on the crossover network.
3. To remove the drive unit from the waveguide, use a 7/16” spanner to undo the four locking nuts.
4. To reinstate the drive unit, simply reverse the above procedure. Ensure when reconnecting the cables
that you not only observe correct polarity (white to positive terminal, yellow to negative) but also that the
cable threads through the HF support brace, otherwise it will prevent the drive unit sitting correctly in
place. Reposition the waveguide correctly and then reinstate the ten bolts, ensuring you have all three
washers for each bolt (shakeproof, flat steel and flat nylon).
5. Reinstate the grille by easing into one slot, then gently applying a curve to the grille and easing it into the
other slot. Reinstate the screws and push the foam back into place.
EMS-152: HF Diaphragm replacement
1. Lie the enclosure on its front.
2. Using a 3mm Allen key, undo the four countersunk M5 bolts holding the rear HF door in place.
3. Disconnect the cables, and using a 3mm Allen key, undo the bolts securing the back cap of the driver.
4. Use a PZ2 screwdriver to remove the screws holding the diaphragm in place.
5. Sit a new diaphragm in place, and reinstate the screws. Reconnect the cables and run a sine wave signal
through the enclosure to ensure that the diaphragm is properly centred before applying final tension to the
diaphragm screws.
6. Reposition the rear door and retighten the M5 countersunk bolts.