Wj-8718-19/Fe Hf Receiver Troubleshooting Procedures - Watkins-Johnson Company WJ-8718-19/FE Instruction Manual

MAINTENANCE
WJ-8718-19/FE HF RECEIVER
Table 4-4. WJ-8718-19/FE HF Receiver Troubleshooting Procedures. (Cont'd)
Step
3. a.
(cont)
b.
c .
d.
4-12
Fault
IF output
dead on all
bandwidths.
If output
dead on 1
or more BWs.
IF output
level out of
limits on 1
Dr more BWs,
Probable Cause
Faulty LO
signals
Faulty A4A7
Faulty A4A2
Faulty A3
Faulty Filter
Switch A4A1 or
A4A3.
[ncorrect
Alignment,
ncorrect USB ?aulty A4A2
F output in
USB Mode.
Additional Test
Check 2nd LO at A2J1:
32.20500 MHz at 0 dBm.
Check 3rd LO at
A4A2-13: 11.155 MHz
at -6 dBm.
Check A4A7-47 for
0 Vdc.
Check A3C1 for 0 Vdc.
Check BW Select volt
ages, pins 15, 17, 19
or A4A1 and A4A3:
♦■3 Vdc for selected
BW.
Check DF Select volt-
ige at A4A2-45: +3 Vdc
n USB Mode.
Corrective Action
Check BCD presets
to A5A2. If correct]
replace A5A2. If no
replace A6A1.
If incorrect replace
A5A1.
If correct, replace
A4A7,repeat step 3b
Table 4-3. If not,
check or replace
A4A6.
Replace A4A2.
Repeat step 3b,
Table 4-3.
If correct, replace
A3, repeat step 3b
Table 4-3. If not,
check or replace
A4A6.
If correct, replace
A4A1 or A4A3, re
peat Step 3b, 3c,
Table 4-3. If not,
check or replace
A6A1 then A6A2.
Perform A4A1
Alignment, Para.
4.3.6.3.2 and A4A7
Alignment, Para.
4.3.6.3.4.
If correct, replace
A4A2, repeat
step 3d, Table 4-3.
If not, check or
replace A6A1 then
A6A2.