Watkins-Johnson Company WJ-8718-19/FE Instruction Manual page 164

Step
1. a.
b.
c .
d.
e.
b.
2.
a.
b.
c .
d.
3.
a .
m n u i l L l i r t i l ^ L
Table 4-4. WJ-8718-19/FE HF Receiver Troubleshooting Procedures.
Fault
Cannot access
BITE tests.
Same
Front Panel
BITE tests
fail.
Receiver
BITE test
fails.
No display
brightness
Same
Incorrect
1+15 V at El
Incorrect
hl5 V at E2
Incorrect
HO V at E3.
Incorrect
1-22 V at C8.
IF output
Jead on all
Bandwidths.
Probable Cause
Power Supply
defective
Digital Control
dead.
Defective Front
Panel.
Defective
receiver module
Misadjusted Dis
play brightness
control.
Defective Fre
quency Display
Faulty Ul
Faulty U2
Faulty CR1,
CR3
faulty LO
signals
Additional Test
Check dc voltages per
Table 4-4,step 2.
Check address/data
bus for signal
activity.
Isolate to Switch
Panel or Encoder
Board.
Check for +24 V
at Ul-1.
Check for -24 V
at U2-3.
Check 1st LO at A1J2:
57.91 MHz at +20 dBm.
Corrective Action
If, defective
replace affected
components.
Replace A6A1, then
then A6A2 if not
good. Otherwise,
replace Front
Panel.
Replace affected
module.
Replace module
indicated by BITE
Adjust A8R2 for
for. proper bright
ness.
Replace A8.
IF correct, replace
Ul. If not, check
U4, C4, C5 and Al.
If correct, replace
U2. If not, check
U4, C3 and Al.
Check CR1/CR3.
Check wiring.
Check BCD presets
to A5A1. If correct,
replace A5A1. If
not replace A6A1
then A6A2.
4-11