TM 11-6625-1633-45
Probable trouble
Correction
Symptom
Deviation meter M1 does not indicate
a. Modulation power supply or circuit
full scale 300KC at any position of
defective.
DEVIATION control knob.
b. Modulation oscillator defective.
Note: MODULATION selector switch
c. Modulation amplifier defective.
c. Repair or replace amplifier.
S2 set at INT SINE position and
d Deviation meter M1 or circuit de-
d. Repair or replace defective parts.
DEVIATION METER RANGE se-
fective
lector switch S3 set at 300KC posi-
tion.
No CW output above 825 MHz with
a. Check mechanical components;
normal output above 825 MHz.
ated mechanical drive defec-
check for defective rf output
tive..
cabling and check low fre-
quency probe Z1 (fig. 3-5).
relay K4.
coaxial relay K4 defective.
c. Adjust or replace microswitch
c. Improper adjustment of mi-
A4S1 (fig. 3-6).
No CW rf output above 825 MHz with
croswitch A4S1 or its cam.
a. Check mechanical components;
normal output below 825 MHz.
check for defective rf output
ciated mechanical drive defec-
cabling and cheek high fre-
tive.
quency probe Z2 (fig. 3-5).
b. Replace power supply.
c. Replace coaxial relay K4.
b. Relay supply voltage defective.
d. Adjust or replace microswitch
c. Coaxial relay K4 defective.
A4S1 (fig. 3-6).
No CW rf output below 1060 MHz
d Improper adjustment of mi-
a. Repair or replace relay A4K1 (fig.
but with normal output below 1060
croswitch A4S1 or its cam.
3-5).
MHz.
a. Relay A4K1 defective.
b. Check operation of potentiometer
A4R20, and associated circuit
b Klystron tracking potentiometer.
resistors A4R2 through A4R7,
A4R20 or circuit components
A4R10 and A4R11 (fig. 3-5
defective.
defective parts.
c. Adjust or replace microswitch
A4S2 (fig. 3-6).
No CW rf output above 1060 MHz
c. Improper adjustment of micro-.
but with normal output below
switch A4S2.
b. Check operation of potentiometer
1060 MHz.
a. Relay A4K1 defective..
A4R20 and associated circuit
b. Klystron tracking potentiometer
resistors A4R8, A4R9, A4R12,
A4R20 or circuit components de-
through A4R19 (fig. 3-5 and 3-
fective.
8); repair or replace defective
parts.
c. Adjust or replace microswitch
A4S2 (fig. 3-6).
No frequency modulation of rf output
c. Improper adjustment of microswitch
a. Repair or replace defective parts.
Note: MODULATION switch S2 set
A4S2 or its cam.
at INT SINE position; INTERNAL
a. Modulation power supply, modu-
MODULATION FREQUENCY
lation oscillator, modulation
selector switch S2 set at any posi-
amplifier, and/or deviation me-
b. Check operation of relay A4K1
tion DEVIATION control knob set
ter defective.
fully clockwise.
b. Relay A4K1 defective.
connectors P13 and A4J4;
check capacitor A4C1 and re-
pair or replace defective parts.
No frequency modulation of rf output
Check operation of relay A4K1 (fig. 3-
below 1060 MHz.
5) and repair or replace defective
Note: MODULATION switch S2 set
Relay
A4K1 or resistors A4R22
parts.
at INT SINE position; INTERNAL
through
A4R28
defective.
MODULATION FREQUENCY
selector switch S2 set at any posi-
tion; DEVIATION control knob
fully clockwise.
3-14
