Watkins-Johnson Company WJ-8718-19/FE Instruction Manual page 166

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iVIAIIN l LNANUE
Table 4-4. WJ-8718-19/FE HF Receiver Troubleshooting Procedures. (Cont'd)
Step
3 d.
(cont)
e .
f.
4.
a .
b.
Fault
Incorrect USB
IF output in
USB mode.
Incorrect LSB
IF output in
LSB Mode.
No IF output
at 42.00000
MHz
IF output dead
at 76.50000
MHz.
No 400 Hz tone
in earphone
(AM Mode)
Probable Cause
Faulty A4A3
Digital
Control is
faulty.
Fault Freq,
Extender
7aulty A4A10
*o Line Audio raulty A4A10
Output (AM
Mode)
Additional Test
Check Wl select
at A4A2-15 for
+3 Vdc.
Verify RF switch.
Check 1st LO output
at FE-A1A1-J5:
232 MHz/-2 dBm
Check RF output at
FE-A1A1-J3
Check 2nd LO output
at FE-A1A2-J2:
189 MHz/-2 dBm
Check IF output
lat FE-A1A2-3:
29.5 MHz/+10 dB
gain from input.
pheck signal at
A4A10-51: 0.7 Vrms
at 400 Hz.
Check signal at
A4A10-55: 0.7 Vrms
at 400 Hz.
Check signal at A4A10-
13 with Rl at max CW:
3 Vrms at 400 Hz
Corrective Action
Replace A4A2 if
OK. If not, then
replace A6A1.A6A2.
Replace A6A2.
Check RF switch
for loss. Replace
if bad.
Replace FE-A1A1A1
then FE-A1A1A2 if
if not good.
Replace FE-A1A1A3
if not good.
Replace FE-A1A2A1
if not good.
Replace FE-A1A2A3
then FE-A1A2A2 if
not good.
Replace FE-A1A1A3.
If incorrect, replace
A4A7. If correct,
perform next test.
If incorrect replace
A4A10. If correct,
check Headphone
Amp. A10A2U1.
If incorrect, replace
A4A10. If correct,
replace Cll.
4-13