Satellite TV System User Manual

5-7
Maintenance
54-0157 Rev. C
5. Remove the Molex connector from J11 on the CPU
board – Fig. 5-5.
6. Remove the 4 nuts and washers and take the gyro
off of the bracket.
7. Remove the antenna gyro gasket.
8. Replacement is the reverse of this procedure.
Antenna Gyro Calibration
1. Connect a PC to the communications port as
described in Section 4.4, “Computer Diagnostics.”
2. Type HALT<cr> while the system is performing
the limit switch initialization routine. The system
will complete the initialization function by finding
the azimuth and elevation switch limits and then
go to the home position.
3. Type DEBUGON<cr> to enter Debug Mode.
4. Type =CALGYRO<cr>. Verify that the Antenna
Gyro Azimuth scale factor is between -0.00090 and
-0.00110 and the Antenna Gyro Elevation scale
factor is between 0.00090 and 0.00110.
5. Type ZAP to restart/reinitialize the system.
5.4.4 Antenna LNB Replacement
Estimated Time to Repair:
1
⁄
2 hour
In the event that the LNB experiences problems, it may be
necessary to replace it. To do so, use the following procedure:
1. Make a note of the current LNB skew angle,
pictured in Figure 5-6 (European systems only).
2. Disconnect the RF cable connector at the LNB.
3. Remove the wing nut and washer from the LNB
clamp – Fig. 5-3.
4. Remove the top of the LNB clamp and remove the
LNB.
5. Place the new LNB in the clamp and reattach the
RF connector.
The LNB receives power from the
IRD via the RF Detector PCB. Be
certain that the IRD is disconnected
from its power source before
removing or reconnecting the LNB.
Skew Angles
LNB Clamp
& Wing Nut
Scribe
Mark
LNB
Figure 5-6
LNB Skew Angle Setting
(European Systems Only)