2. Service
Assembly/Module Diagnostic Trees (Diagnostic Section 3)
108
3.6.2.0 320-MHz Signal Test
1 Adjust spectrum analyzer input attenuation for a +30 dBm. maximum signal.
2 Disconnect cable from A15J4.
3 Connect the free end of the cable to the spectrum analyzer.
4 Verify the presence of a 320-MHz signal with at least +18 dBm amplitude.
5 Reconnect cable to A15J4.
QUESTION: Does the analyzer show a 320-MHz signal with at least
+18 dBm amplitude?
If Yes: Go to, 3.6.3.0.
If No: Go to, 3.4.1.0 (A9 diagnostic tree).
3.6.3.0 A15J3 Signal Test
1 Disconnect coax cable from A18J4.
2 Connect free end of the cable to a spectrum analyzer with 50 input
impedance.
3 Verify the 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 analyzer show a signal with frequency between
70 and 110 MHz and amplitude between -25 and -10
dBm.?
If Yes: Go to, 3.6.4.0.
If No: Remove power, replace A15, and retest.
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