2. Service
Assembly/Module Diagnostic Trees (Diagnostic Section 3)
117
3.8.2.1 A5 87.368230-MHz Input Cable Test
1 Disconnect cable from A5 output connector.
2 Connect A5 output connector to a scope 50 input (If a 50 input is absent,
use the high-impedance input with a 50 coaxial-feedthrough terminator at
the scope end of the coax).
3 Verify presence of an 87.368230 MHz (100 kHz.) sine wave
with at least 0.4 Vp-p amplitude.
QUESTION: Does the scope show an 87.368230 MHz (100 kHz.)
sine wave with at least 0.4 Vp-p amplitude?
If Yes: Remove power, replace the cable between A5 and A18J1,
and retest.
If No: Go to, A5 diagnostic tree.
3.8.3.0 A15 70-110 MHz Input Test
1 Disconnect coax cable from A18J4.
2 Connect free end of the cable to the 50 input of a spectrum analyzer.
3 Verify presence of a signal with frequency between 70 and 110 MHz and
amplitude between -25 and -10 dBm.
4 Reconnect cable to A18J4.
QUESTION: Does the spectrum analyzer verify the signal in step 3?
If Yes: Go to, 3.8.4.0.
If No: Go to, 3.8.3.1.
3.8.3.1 A15J3 and A18J4 Cable Test
1 Disconnect cable from A15J3.
2 Connect A15J3 to the 50 input of a spectrum analyzer.
3 Verify presence of a signal with frequency between 70-110 MHz and
amplitude between -25 and -10 dBm.
4 Reconnect cable to A15J3.
QUESTION: Does the analyzer verify the signal in step 3?
If Yes: Remove power, replace the cable between A15J3 and A18J4,
and retest.
If No: Go to, 3.8.3.2.
To Next Page
Loading...
Need help?
General
