Resistance Selection Chart

TM 11-5820-509-35

(27) occur between 550- and 650-kHz,

NOTE

substitute a new value for resistance

If the error line voltages (measured at

R144 (fig. 3-56) from the following

jacks J5 and J6) are not within the

table using the procedure in step i to

limits specified in steps (4) through

obtain

optimum

operating

(21), or if the error line voltage

characteristics.

reversals measured in steps (24) and

Resistance Selection Chart

Value

Part No.

Value

Part No.

10.0 1.0 ohms

RC07GF100K

470 47 ohms

RC07GF471K

82.0 8.2 ohms

RC07GF820K

680 68 ohms

RC07GF681K

150 15 ohms

RC07GF151K

820 82 ohms

RC07GF 821K

220 22 ohms

RC07GF 221K

1000 100 ohms

RC07GF102K

330 33 ohms

RC07GF331K

1600 150 ohms

RC07GF152K

voltage at jack J4 remains at 1.05 volts peak-to-peak

i. Error Voltage Balance Adjustment.

approximately.

NOTE

k. SMO Mixers Test.

Perform these procedures only if the

(1) Connect signal generator no. 1 to the 5-

error voltages or voltage reversals in

14 MHZ INPUT jack on the front of the test fixture.

step h are beyond acceptable limits.

(2) Connect the oscilloscope probe to the

(1) On the test fixture, set switch S1 to 0 and

primary of transformer T1 (fig. 3-56, at junction with

switch S2 to 6.0.

coaxial input cable near jack J2) on terminal board TB1.

(2) Connect the signal generator output

(3) Adjust the output frequency of signal

terminals to the common junction of T3-C165R147 (fig.

generator no. 1 to 5.0 MHz at an output level of 2.4

3-56) and adjust the output frequency to 660 kHz at an

volts peak-to-peak on the oscilloscope.

output level of 0.1 volt rms.

(4) Connect signal generator no. 2 to the 2.512.5 MHZ

(3) Refer to figures 3-55 and 7-14. Connect

INPUT jack on the front of the test fixture, and move the

the oscilloscope alternately to the collector circuit of

oscilloscope probe to jack J3 (fig. 3-14).

transistor Q9 (common junction of Q9-C25-L3) and the

(5) Adjust the output frequency of signal

collector circuit of transistor Q12 (common junction of

generator no. 2 to 2.55 MHz at an output level of 6.0

Q12-C32-L6) while substituting values for resistor R144

volts peak-to-peak on the oscilloscope.

(fig. 3-56).

(6) Connect the oscilloscope probe to jack J4

(4) Select a suitable value of resistance for

(fig. 3-14) and observe that the mixer output level is 1.5

R144 from the chart above that provides maximum 10-

0.4 volts peak-to-peak.

kHz modulation at both Q9 and Q12 collector circuits.

(7) Repeat step (2) and adjust the output

NOTE

frequency of signal generator no. 1 to 6.0 MHz at an

Some compromise in this resistance

output level of 2.1 volts peak-to-peak on the

value will be required to obtain

oscilloscope.

nearly equal levels of modulation at

(8) Repeat step (4) and adjust the output

both collector circuits.

frequency of signal generator no. 2 to 3.55 MHz at an

j. Anti-lock Test.

output level of 4.4 volts peak-to-peak on the

(1) Connect the signal generator output

oscilloscope.

terminals to the common junction of T3-C165R147 (fig.

(9) Repeat step (6). The mixer output shall

3-56) and adjust the output frequency to 700 kHz at an

be 1.5 0.4 volts peak-to-peak.

output level of 0.1 volt rms.

(10) Repeat step (2) and adjust the output

(2) Connect the oscilloscope to jack J4 on the

frequency of signal generator no. 1 to 7.0 MHz at an

module.

output level of 1.8 volts peak-to-peak on the

(3) Observe that the ANIT-LOCK lamp on the

oscilloscope.

test fixture is lit.

(11) Repeat step (4) and adjust the output

(4) Increase the signal generator output level

frequency of signal generator no. 2 to 4.55 MHz at an

until the ANTI-LOCK lamp goes out. The voltage at jack

output level of 6.0 volts peak-to-peak on the

J4 shall be 1.05 volts peak-to-peak on the oscilloscope.

oscilloscope.

(5) Lower the signal generator output level

until the ANTI-LOCK lamp lights, and observe that the

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