System information

Coastal 24 & 30 Ku-Band TVRO Maintenance
6-7
6.6. Replacing a Defective LNB
Follow the procedure below to install and align a replacement LNB. After the LNB is installed, the POL
OFFSET parameter must be re-optimized.
1 Adjust the Polarization setting in the
Antenna Control Panel to read 090. The
Polarization Motor will rotate the current
LNB to a vertical position (straight up).
2 Turn power OFF at the Antenna Control
Panel.
3 Remove radome top.
4 You may need to rotate the antenna to
gain access the back of the dish.
5 Note that the body of the current LNB is
vertical (straight up) and is aligned with a
line drawn on the counterweight mounting
bracket.
6 Loosen the Allen set screws on the
existing LNB mounting collar (three set
screws, 120 degrees apart) and remove it
from the mounting collar.
7 Insert the new LNB (same style) into the
mounting collar, assure it is seated all
the way into the mounting collar tube,
rotate the LNB as needed to align the
center of the body of the LNB to a vertical
position (straight up) and tighten the set
screws. All Linear and circular LNBs
must be aligned this way to prevent them
from hitting the Motor or Pot during
polarization drive.
8 Transfer the coax cables from the old
LNB to the new LNB, assure that the
correct color coax is attached to the
correct port on the LNB.
9 Re-install the radome top and tighten
radome hardware. Do not exceed 24 in-lb
(21 kg-cm) torque.