5-8
A Guide to TracVision Cruiser
5.4.4 Antenna LNB Replacement
Estimated Time to Repair:
1
⁄
2
hour
The LNB (Item 19) receives preamplifier operating power from
the IRD via the RF Detector PCB
– Fig. 5-3
. Be certain that the
IRD is disconnected from its power source before removing or
reconnecting the LNB.
1. Disconnect and label both RF coaxial connectors
at the LNB. Remove 4 pan head screws and
washers (Items 57 and 58)
– Fig. 5-3
.
2. Remove LNB clamp (Item 23)
– Fig. 5-3
.
3. Remove LNB.
4. Replacement is the reverse of this procedure.
Check the rotation to ensure that the LNB is not
striking any wires or the baseplate.
Antenna LNB Normalization and Stability Test
1. Type
HALT<cr>
to put the system into Idle
Mode.
2. Type
DEBUGON<cr>
to put the system into
Debug Mode.
3. Use the PC 2, 4, 6, and 8 keys along with the
Signal Strength Display Meter on the TV screen
to peak the RF Signal.
4. Type
=CALLNB<cr>
to start the LNB
Normalization Function.
Note: The CALLNB Function requires the
antenna to be pointed directly at the satellite
peak before performing this routine.
5. The system must respond with the following
message:
CALLNB: PASS
. If the system
displays
CALLNB: FAIL
, return to step 1 and
retry the procedure, making sure to achieve the
highest possible RF signal peak.
6. Record the Cold Sky Average and the RFGAIN
value reported in step 5.
7. Type
ZAP<cr>
. The system will re-initialize
using the new RFGAIN and RFOFFSET scale
factors displayed following step 5.
When replacing the LNB, make
certain to restore it to its original
orientation, as shown in Figure 5-3.
