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The following procedures detail verification and fault isolation.
5.4.1
Initial Check
1.
Verify that the PC wafer in AlO 11 on receiver rear panel matches available line
voltage.
2. Energize Receiver by turning POWER ON switch to
'~ON"
position.
3. Observe edge lighting and Liquid Crystal Displays (LCDs). If edge lighting is'present
and LCD displays coritain data, there is a reasonable confidence factor (80%) that
the Power Supply (AID) is working properly. Proceed to step
4.
IF: a. Edge lighting is not present, the +15 volts from the AlO is malfunctioning.
Check this voltage through to AlO and correct the malfunction.
b. Edge lighting is present, frequency display contains mostly zeroes, and
no mode indication is present, either the wafer does not match available
line voltage, or the A6A2 Microcomputer Assembly is faulty and should
be replaced.
4. Depress the LOCAL/REMOTE pushbutton switch on the front panel. The LCD
display should indicate a change in receiver control from no display to REMOTE or
vice versa. Repeated pressing of the LOCAL/REMOTE pushbutton switch should
alternate the display between no display and REMOTE indications.
IF: a. The Receiver indicates that it is in the REMOTE.mode, and depressing the
LOCAL/REMOTE pushbutton does not change the display, either the
A6A2 Microcomputer Assembly or the A9 Front Panel Assembly is faulty
and must be replaced.
b. The receiver display does not indicate that it is in REMOTE, further isola-
tion is possible. Depress the METER RF / AF pushbutton switch. The
meter display should change correspondingly. If it does change, the
REMOTE/LOCAL pushbutton switch is probably bad and the A9 Front
Panel Assembly should .be replaced. If the meter display does not change;
initialize the Receiver by depressing the LOCK and AM pushbuttons .
simultaneously and allow the Receiver to initialize (approximately one
minute). Once again attempt to change from LOCAL to REMOTE and
back; and from RF to AF meter indications. If the display still will not
change, the fault is probably on the A6A2 Microcomputer Assembly which
should be replaced.
NOTE
Once steps 1 through 4 have been successfully ac-
complished, it can be assumed with 60% confidence
that both the A6A2 Microcomputer and the A9
Front Panel Assemblies are functional. To increase
the confidence factor, perform step 5.
5. Ensure that the Receiver is under LOCAL control (indicated by absence of REMOTE
in LCD display). Depress the ENTER pushbutton switch momentarily, followed by
5-5
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