TM 9-4935-294-15/2
Table 3-12. L-Band Rf Head Test Chart
Test equipment control
Rf head control
Possible cause
Step
positions or operation
positions or operation
Normal indication
of malfunction
Corrective measure
1
Set up signal utilizing
Set FREQUENCY-MC
Power meter indicates 5
R1505 out of adjustment
Adjust R1505 as indicated
L-band rf head under test
control to 1500 MEH.
mw.
or defective
in technical bulletin TB
for leveled operation as
9-4931-297-5O or re-
shown in figure illustrating
place, if defective.
setup for signal source lev-
Broken connector pin in
Replace broken pin.
eling in chapter 2, section
P701 (rf head connec-
II, of TM 9-4931-294-15/1.
tor).
Operate signal source in
Defective resistor R1507
CW mode of operation and
Replace defective resistor.
connect 6-db fixed coaxial
or R1401.
attenuator in place of co-
axial termination at output
Defective BWO tube
Replace BWO tube an in-
of setup. Connect thermistor
dicated in paragraph
mount-power meter combi-
4-18.
nation to the 6 db attenua
tor and met RF LEVEL-
LEVEL ADJ control for an
indication of 5 mw on
power meter.
2
Disconnect 6-db attenuator
Power meter indicates
Defective directional
Replace directional
and thermistor mount and
0.2 mw.
Coupler DC101.
coupler DC1010
connect coaxial termination
to output of setup. Remove
interconnection cable from
PHASE LOCK connector,
connect thermistor mount-
power meter combination in
its place, and operate power
meter
3
Same as 2 above.
Slowly adjust FRE-
The 02 mw indication
R1505 out of adjustment
Adjust R1505 indicated
QUENCY-MC control
on power meter does
or defective.
in TB 9431-207-50
not vary by more than
through its entire
or replace, if defective.
Range.
0.5 db.
Defective BWO tube.
Replace BWO tube as in-
dicated in paragraph
4-18.
4
Disconnect thermistor mount
Adjust FREQUENCY-
Frequency measure-
Helix voltage-shaper cir-
Adjust the circuits indi-
ment system cor-
cuit out of adjustment t
and replace interconnection
MC control in 100 MHz
cated as outlined in TB
cable to the PHASE LOCK
steps beginning at 1000
respond to within 2% of
or defective.
9-4931-297-50 or, if de-
MHz, through its entire
connector. Connect free
fective locate and replace
quency measurement
on the rf head FRE-
defective component.
system (refer to figure
QUENCY-MC counter.
Illustrating setups for
Change 1 3-40I