Halo-C: Removing The Lf Drive Unit - EM Acoustics Halo Compact System User Manual

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attach the washers and Nyloc nuts to the studs and retighten until firm. Check
that the gasket around the rear door is complete, and replace if necessary. You
can then reinstate the wadding (ensure it does not block the port) and reconnect
the cables to the crossover PCB on the access door. Note the polarity: Brown
cable to LF +, blue cable to LF -, white cable to HF +, yellow cable to HF -. Also
note that the cables are an exact length, meaning the door only fits onto the
enclosure one way round. Reinstate the six M4 socket cap bolts that secure the
door, along with their flat and spring washers, and retighten. You can then lie the
enclosure flat and reinstate the grille and grille screws to return to normal service
– note that the badge on the grille goes over the 8" drive unit.

HALO-C: Removing the LF Drive Unit

1. Follow steps 1-4 above to remove the AMT drive unit. This then gives access to
the four M5 socket cap bolts that secure the 8" drive unit into the enclosure (two
of these are obscured by the AMT waveguide).
2. Remove the four socket cap bolts holding the LF drive unit in place using a 4mm
Allen bit – ensure to collect both the flat and spring washers for each bolt. Do not
undo the four dome head socket bolts – these secure the phase bung to the 8"
drive unit! Gently lift the drive unit out of the enclosure – the cables have already
been disconnected so will come free with the drive unit. Please make a note of
drive unit polarity for future reinstatement (brown cable to positive, blue cable to
negative). Note that the phase bung is attached to the 8" drive unit – this can be
removed if required using a 3mm Allen key or bit, and an 8mm spanner. If you do
remove this and need to reinstate it, ensure the axis of the phase bung is
perpendicular to the drive unit terminals or the 8" drive unit will not fit back into
the enclosure.
3. To reinstall the 8" drive unit, first check that the phase bung is in the correct
orientation as described above, and that the sealing gasket around the flange of
the drive unit is complete. Then, sit the 8" drive unit back in its location and
reinstate the four M5 socket cap bolts (with flat and spring washers) and tighten
until firm.
4. Now, follow step 6 above for reinstating the AMT drive unit to reassemble the
HALO-C enclosure.
HALO Compact User Manual
V7 December 2019