TM 11-6625-828-45
(2) Use a screwdriver to tune the "A"
connected to the vacuum tube voltmeter as specified in d
crystal capacitors (C143A and C149A) and the "B"
crystal capacitors (C143B and C149B) to resonance at
above, check the RF meter as follows:
the crystal frequencies.
(1) Recheck the RF and 7%M meters
(3) Interchange the crystals and repeat
zero adjustment. Adjust the test set RF METER SENS
(2) above.
control until the needle of the RF meter indicates exactly
(4) Check that the installed crystal
at the red LEVEL SET line.
frequencies agree with the frequency tabs located on the
(2) Check the range of the test set RF
test set front panel above the MC switch. With the
LEVEL SET as indicated on the vacuum tube voltmeter
multimeter connected to the test set RF-OUTPUT 1
while turning the control from the fully counterclockwise
VOLT connector, tune for maxi- mum output at both
to the fully clockwise positions. Place the test set MC
frequencies.
switch in the "A" crystal position and repeat the RF
LEVEL SET control range check.
vacuum tube voltmeter to make the following test set
(3) Adjust the RF LEVEL SET control until
voltage checks:
the RF meter needle indicates exactly at the red LEVEL
(1) Connect the test set to a variac-con-
SET line.
trolled, 115-volt, 60-cycle power source and measure the
(4) Use the multimeter to check the resist-
output voltage of the high voltage regulator at pin 3 of
ance value of the test set 51-ohm termination cap.
electron tube V114. The vacuum tube voltmeter
Replace the external 51-ohm termination and the
indication should be between 390 and 420 volts.
voltmeter with the 51-ohm termination cap and check to
(2) Vary the input voltage from 100 to 130
see that the RF meter needle indicates at the LEVEL
volts and record the change in regulator volt- age output.
SET line within 1/32 inch.
The change should not exceed 2 volts from the reading
(5) Deleted
f 7%M Meter Test (fig. 4-5). Check the zero
in step (1).
(3) Restore the input voltage to 115 volts
set condition of the RF and %M meters as instructed in
and measure the high voltage audio supply volt- age at
the orange wire connection at capacitor C160. The
(1) Connect the multimeter between
vacuum tube voltmeter indication should be between 245
terminal 3 (green wire with red trace) of the test set RF
and 275 volts.
unit and the negative (-) terminal of the RF meter and
(4) Measure the high voltage RF supply
connect the vacuum tube volt- meter across the
voltage at the pink wire connection at capacitor C161.
multimeter.
The vacuum tube voltmeter indication should be
(2) Set the test set MODULATION switch
between 185 and 215 volts.
to 30-
and rotate the 30- MOD control fully
(5) Connect the vacuum tube voltmeter
counterclockwise.
between the ring and the sleeve of a standard-micro-
(3) Adjust the test set PLATE B trimming
phone jack and insert the plug in the MIC jack of the test
capacitor to obtain maximum detuning effect and record
set. The microphone circuit current indication on the
the voltage indicated by the multimeter as E0
vacuum tube voltmeter shall be between 1.62 and 1.98
(approximately 7.2 volts).
volts de.
(4) Retune the PLATE B trimming
d. RF Output Test. With the test set MC
capacitor for the maximum RF meter indication. Use the
switch set to the "B" crystal position, allow the test set to
test set RF LEVEL SET control to reset the RF meter
warm up for at least 30 minutes and then perform the
needle to the red LEVEL SET-fine and record the voltage
following tests:
indicated by the multimeter as El (approximately 37
(1) Remove the termination cap from the
volts).
test set RF OUTPUT 1 VOLT connector J105 and
(5) Compute EAC from the following
replace it with an external 51-ohm termination.
formula:
(2) By means of the test set RF LEVEL
SET control, adjust the RF output voltage to 1.0 volt as
EAC = 0.212 (E1+ 3 - E0)
indicated on the vacuum-tube voltmeter connected
across the external 61-ohm termination.
Change 1 5-2
