Symptom
Probable trouble
Correction
1. Line cord connected to power source
Blown fuse F1 and/or F2.
Replace blown fuse. If fuse blows
and POWER switch is in STANDBY
again, check the primary winding
position. The 50-100, the 100-200,
and all filament windings of T1.
and the 200-400 indicator lamps fail
Check for a shorted rf bypass
to light when the FREQ. RANGE-MC
capacitor ill the filament circuits.
switch is rotated to these positions.
Check for a filament-to-cathode
short in the tubes whose cathodes
are grounded directly.
Open filament winding (terminals 8
Replace T1.
and 9) or primary winding
(terminals 1 and 2) of T1.
Defective POWER switch or power
Replace S4 or power cable.
cable.
2. POWER switch in STANDBY position.
Defective indicator lamp I 1, I 2, or
Replace the defective lamp.
One or twoindicator lamps fail
I 3.
to light when the FREQ. RANGE-MC
switch is rotated through its three
positions.
3. Fuse F1 and/or F2 blows when.
Shorted rectifier tube V15
Replace V15.
POWER switch is set to ON posi-
Shorted filter capacitor C84 or C85
Replace C84 or C85.
tion.
Defective transformer
Replace T1.
A short in any of the dc circuits in
Make resistance measurements at the
the signal generator.
tube socket of all tubes in the
signal generator.
4. Power switch in ON position. UT-
O
Defective rectifier tube V15 or regu-
Replace V15 or V12.
PUT meter is at center scale and
lator tube V12.
there is no rf output on all three
Open high-voltage winding (terminals
Replace T1.
positions of the FREQ. RANGE-
3, 4, and 5) on T1.
MC switch.
Defective POWER switch S4
Replace S4.
5. MODULATION switch in the OFF
Defective oscillator tube V5, first
Substitute tubes known to be good,
position. Low, or zero, rf output
doubler V6, or rf amplifier V7.
first for V5, then V6, and finly
la
on all three ranges of the FREQ.
for V7.
RANGE-MC switch.
A defective component in the
Make voltage and resistance mea-
circuitry of the above mentioned
surements at the tube sockets of
tubes.
V5, V6, and V7.
6. MODULATION switch in OFF posi-
Defective second doubler V8
Substitute tubes known to be good
tion. Low, or zero, rf output on the
for V8.
100-200 and 200-400 mc positions
A defective component in the circuitry
Make tube-socket voltage and resist-
of the FREQ. RANGE-M switch.
C
of VS.
ance measurements on V8.
7. MODULATION switch in OFF posi-
Defective third doubler tube V9
Substitute tubes known to be good
tion. Low, or zero, rf output on
for V9.
the 200-400 me position of the
A defective component, in the
Make voltage and resistance measure-
FREQ. RANGE-MC switch
circuitry of V9.
ments at the tube socket of V9.
Defective attenuator
Replace attenuator.
8. MODULATION switch in OFF position.
S5 defective
Replace S5.
Low, or zero, rf output on one
Attenuator connecting cable open
Replace cable.
of the three positions of the FREQ.
or shorted.
RANGE-MC switch.
Defective attenuator
Replace attenuator.
9. Rf output is equal to 100,000 micro-
OUTPUT TEMPERATURE COM-
Adjust R129 and R130.
volts. OUTPUT meter does not
PENSATION potentiometer R129
indicate center scale.
and/or OUTPUT CAL potentiometer
R130 misadjusted.
Defective bolometer RT4 or defective
Check parts in bolometer bridge circuit.
component in the bolometer
Replace where neessary.
c
bridge circuit.
Defective OUTPUT meter
Replace M2.
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