TM9-4935-294-15/2
Table 3-9. Operational Check and Troubleshooting Chart of Attenuation Measurement Setups
Step
Procedure
Normal indication
Possible cause of malfunction
Corrective measure
I
Adjust AGC SET control to ob-
AGC VOLTS meter indicates 5 on
Defect within microwave receiver.
Refer to microwave recei-
tain an indication of 5 on the
the topmost scale
ver manual
topmost scale of AGC VOLTS
meter (this meter setting is
also marked VIDEO).
2
Turn ZERO-NORMAL switch to
NULL meter on microwave re-
Defect within microwave receiver
Refer to microwave re-
ZERO and by means
ceiver indicates a null
ceiver manual
METER-ZERO control,set
NULL meter pointer to NULL
mark.
3
Return ZERO-NORMAL switch
Signal source no. 1 operating at
Defect within signal source no. 1.
Refer to paragraph 3-13 of
to NORMAL Operate signal
this section.
source no. 1 in leveled CW
mode of operation and set cor-
Defect within power measuring
Refer to paragraph 3-8 of this
rect rf power level Phase-lock
equipment.
section.
signal source no. 1. For maxi-
Defect within frequency measuring
Refer to paragraph 3-4 or 3-5
output of signal source
equipment.
of this section.
no. 1, using digital counter and
frequency converter.
4
Operate signal source no. 2 in
Defect within signal source no. 2.
Refer to paragraph 3-13 of this
leveled CW mode of operation
indication at signal source no. 2.
section
at a frequency 30 MHz away
from signal source no. 1 free-
Defect within power measuring
Refer to paragraph 3-8 of this
Quincy. Set correct rf power
equipment
section.
level. For maximum accuracy.
adjust frequency output of
Defect within frequency measuring
Refer to paragraph 3-4 or 3-5
signal source no. 2 using dig-
equipment.
this section.
tall counter and frequency con-
verger.
5
Set MIXER XTAL CURRENT
CRYSTAL CURRENT meter in-
Defect within microwave receiver.
Refer to microwave receiver
switch on receiver to INT for
dictates as described in procedure.
manual.
measurements below 1 GHz
and to EXT for measurements
Defective mixer.
Replace mixer.
above 1 GHz. Adjust level-set
attenuator no. 2 until CRYS-
TAL CURRENT meter indica-
tion is between 0.5 & 1.5 ma.
Adjust level-set attenuator no. 2
to obtain a null on receiver NULL
meter.
6
Display shown in section A of the
Insufficient power output of
Increase RF LEVEL-LEVEL
demodulated IF frequency out
signal source.
ADJ ctrl on BWO power supply.
Change 1 3-24