StarBand 75E, Информационные бюллетени по обслуживанию и ремонту, Страница: 19 / 28

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Field Service & Maintenance Bulletins
19
should read between 13 and 18 V DC. If there is no voltage present there is typically
an
open or short somewhere in the IFL. See the previous two figures, labeled “ IFL With
an Open Circuit ” and “ IFL With a Short Circuit ”. If there is a short in the IFL, the
satellite modem will not function normally. You will be able to see this, if you check
the LEDs.
DC Continuity Check – Receive Line Amplifier
If a line amplifier was installed, check the voltage at the input and output of the line
amplifier to determine if it has failed. A DC resistance test can be performed, to
determine if the IFL has an open or a short. In either case, the IFL must be replaced.
DC Continuity Check – Transmit IFL
Remove the transmit IFL cable from the
RF-Out
connector and install the Type
F/male-male coaxial adapter. Place the multimeter's red probe on the center conductor
and the black probe on the outer shell of the coaxial adapter. The DC voltage reading
should nominally be between 22 and 24 V DC. After checking this voltage, remove the
coaxial adapter and re-install the transmit IFL cable on the satellite modem
RF-Out
connector.
Caution
Do not use a DigiSat II to measure the DC voltage of the transmit IFL, as
it is only rated to 18 V DC and will be damaged with higher voltages.
Remove the transmit IFL cable from the ODU. Check the DC voltage of the transmit
IFL at the ODU end using the multimeter, as described previously with the receive IFL,
except the voltage should be between 13 to 24 V DC. If there is no voltage present,
there is typically an open circuit, somewhere in the IFL. If there is a short in the IFL,
the satellite modem will not function properly.
DC Continuity Check – Transmit Line Amplifier
If a line amplifier was installed, check the voltage at the input and output of the line
amplifier to determine if it has failed. A DC resistance test can be performed, to
determine if the IFL has an open or a short. In either case, the IFL must be replaced.