2. Service
Assembly/Module Diagnostic Trees (Diagnostic Section 3)
99
A9 Diagnostic Tree
(A/M Subsection 4)
This subsection describes the A9 Frequency Multiplier module diagnostic
tree.
3.4.1.0 A9 Module Power Checks
1 Check the -12V and +5V terminals on A9 with a DMM and verify that: -12V is
between -12 and -12.5V to chassis
2 Verify +5V is between 5.25 and 5.5V to chassis.
QUESTION: Are power-supply voltages correct?
If Yes: Go to, 3.4.2.0.
If No: Remove power, replace A9, and retest.
3.4.2.0 10-MHz Signal Test
1 Disconnect semi-rigid cable from A9J5.
2 Connect free end of the cable to a scope with 50 input impedance.
(If the scope doesn't have a 50 input, use the high impedance input with a
50 coaxial feedthrough terminator installed at the scope end of the coax).
3 Verify presence of 10-MHz undistorted sine wave with at least
1 Vp-p amplitude.
4 Reconnect cable to A9J5.
QUESTION: Does the scope show a 10-MHz undistorted sine wave
with at least 1 Vp-p amplitude?
If Yes: Go to, 3.4.3.0.
If No: Go to, 3.4.2.1.
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