TM 11-6625-255-14/TO 33A113170-1
KEY to fig. 7-10:
A2 Torsion spring
0 6 Dial shaft collar
A3 Disk spring
0 7 Idler shaft
A5 Frequent dial
0 8 Coupler shaft
A8 Dial window
0 9 Dial hub
A62 Mounting bracket
0 10 Coupler shaft bearing
A63 Mounting board
0 11 Dial shaft bearing
A64 Spacer
0 12 Dial shaft bearing
C12 Variable capacitor
0 13 Flat pulley
C13 Variable capacitor
0 14 Groove pulley
C14 Fixed capacitor
0 15 Idler pulley
E32 Dial shaft bearing spacer
0 18 Dial shaft
E33 Disk shaft bearing spacer
0 19 Cone pulley
E60 Clamp
0 20 Back drive cable
H60 Cable clamp
0 21 Front drive cable
H61 Cable clamp
0 22 Drive shaft
I 1 Dial lamp
0 60 Bearing washer
0 1 Disk shaft bearing
0 61 Bearing washer
0 2 Shaft disk
0 62 Bearing washer
0 3 Dial shaft
0 63 Bearing washer
0 4 Coupler shaft collar
XI 1 Lampholder
0 5 Coupler
f.
Set the meter range switch to .03 R.M.S.
f.
Set the meter range switch to 3.0 R.M.S.
VOLTS.
VOLTS. Record the reading obtained on the
g. If the meter pointer rests at zero, or
meter.
indicates at not more than one division,
g. Adjust the voltage output of the signal
adjustment for hum balance is not necessary.
g e n e r a t o r to produce a reading of 0.08 volt on the
spectrum analyzer meter. Record the reading on
NOTE
the vtvm.
The maximum allowable reading is
h. Adjust the signal generator for 10,000 Hz at
0.0007 R.M.S. VOLTS.
the same voltage output recorded on the vtvm (g
a b o v e ) . Set the meter range switch to .10 R.M.S.
h.
If the meter pointer does not rest at zero,
VOLTS. The spectrum analyzer meter should
turn the FREQUENCY tuning dial to 60. If the
indicate 0.08 3 percent R.M.S. VOLTS. If this
combination of adjusting the FREQUENCY
r e a d i n g is not obtained, adjust trimmer C25 until
tuning knobs and the BALANCE control at near
the meter indicates 0.08 3 percent R.M.S.
6 0 Hz results in a zero-meter indication, 60-cycle
VOLTS.
hum is present in the circuit. Turn the function
i. Adjust the signal generator for 100,000 Hz at
switch to SET LEVEL and adjust HUM BAL
the same voltage output recorded on the vtvm (g
control R41, at the rear panel, for a zero-meter
above). The reading on the spectrum analyzer
indication. If turning the FREQUENCY tuning
m e t e r should be 0.08 3 percent R.M.S. VOLTS.
dial to 60 Hz does not result in a zero-meter
If this reading is not obtained, adjust C25 until
indication, the meter is indicating noise. Check
the meter indicates 0.08 3 percent R.M.S.
V2, V3, V4, V5, and V6.
VOLTS.
i. If a zero-meter indication cannot be obtained
j. Repeat the adjustments described in h and i
b y adjusting R41, replace V2 and readjust R41 for
above until the 0.08 3 percent R.M.S. VOLTS
a zero-meter indication.
reading is obtained for both 10,000 and 100,000
j. If the meter cannot be zero-set by replacing
Hz without requiring further readjustment.
V2, replace the original V2 in its socket. Repeat
k. Set the meter range switch to 100 R.M.S.
this test for tubes V3, V4, V5, and V6.
VOLTS.
716. Alignment of Vtvm Section
l. Adjust the signal generator for 1,000 Hz.
Calibrate the vtvm section as follows:
Adjust the signal generator voltage output to
a. Connect the signal generator and the vtvm
produce a reading of 80 R.M.S. VOLTS on the
to the METER binding posts. Adjust the signal
spectrum analyzer meter. Record the reading on
generator for 1,000 Hz at exactly 1 volt.
the vtvm.
b. Turn on the spectrum analyzer and allow it
m. Adjust the signal generator for 10,000 Hz
to warm up for 15 minutes.
c. Set the function switch to METER.
The spectrum analyzer meter should indicate 80
d. Set the meter range switch to 1.0 R.M.S.
3 percent R.M.S. VOLTS. If this reading is not
VOLTS.
obtained, adjust trimmer C20 until the meter
e. Adjust variable resistor R62 (VM GAIN) for
indicates 803 percent R.M.S. VOLTS.
a meter reading of 1.0 R.M.S. VOLTS on the top
n. Adjust the signal generator for 100,000 Hz
m e t e r scale.
at the same voltage output recorded in l above.
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