TM 11-6625-847-45
RCVR IF AGC SYNC switch A2S6 on tray A1A2 to OFF.
of POWER switch A1S2 to SERV SEL switch A1S1,
The output of IF oscillator module A1A4, when selected
through thermal activated switch S1 to blower motors B1
by switch A1S8, is 1.7500 mc and is connected directly
and B2, and to test set connector J1. The SERV SEL
to connector J1.
switch controls the mode of operation of the test set in
d. Megacycle frequency selection is accomplished
the first four positions, OFF, OVEN ON, STBY, and
SSB/NSK, and stimulates the functions that are
by MC FREQ 10 MC switch A1S9, .1 MC switch A1S11,
normally supplied to test set connector J1 by the
and .1 MC switch A1S10. These switches are used to
SERVICE SELECTOR switch on the front panel of the
RT-662/GRC in positions OFF, OVEN ON, STBY,
common module tray A1A1 and synthesizer test tray
SSB/NSK, FSK, AM and CW. The SERV SEL switch in
A1A3 and provide the five-wire coding inputs to the AM-
any position other than OFF supplies +27-volt dc
3349/GRC-106 at PA CONTROL connector A1J12.
primary power to the regulator section of dc-to-dc
e. Dc-to-dc converter module A2 on the test set is
converter and regulator module A3. Figure 6-3 is the
controlled by an interlock jumper wire on connector J1
test set schematic diagram.
of driver, discriminator, and antenna coupler tray A1A5.
When tray A1A5 is connected to the test set, the +27-
primary power to +20 volts dc. The ON position of the
volt dc primary power is supplied to module A2 for
POWER switch on one of the module testing trays,
conversion to + 200 volts dc. The +200-volt dc power is
when connected to the test set, supplies +27-volt dc
then connected back to tray A1A5 for module excitation.
primary power to the converter section of module A3.
f. The resistive loads supplied by the test set to
The converter section of module A3 converts the +27-
the module testing tray are as follows: a 2,400-volt dc
volt dc primary power to + 125 volts dc, -33 volts dc and
load, a 500-volt dc load, a 200-ohm, 250-watt resistor,
6.3 volts ac. The + 20-volt dc output of module A3 is
and a 420-ohm, 250-watt resistor. The 2,400-volt dc
used on the test set as B+ supply voltage for
load is controlled by seven-position 2400 VDC LOAD
intermediate frequency (if) oscillator modules A1A2,
switch A1S3 by selecting the number of resistors in
A1A3, and A1A4.
For operating voltages, pulse
parallel with the input leads of the load. The 500-volt dc
generator module A1A1 requires the +20-volt dc and the
load is controlled by 500 VDC LOAD switch A1S7 as
*33-volt dc outputs for the dc-to-dc converter and
either a low or high current load by the paralleling of two
regulator module A3.
fixed resistors across the input leads.
c. Two-tone select switch A1S8 controls the output
g. Pulse generator module A1A1 supplies a 1
of the three IF oscillator modules, A1A2, A1A3, and
microsecond (usec) pulse and either an 85-usec positive
A1A4, by switching the +20-volt dc B + supply voltage
pulse or a 150-usec negative pulse to the front panel of
either on or off to one or more of the modules. Modules
the test set at OUTPUTS connectors 1, 2, and 3,
A1A2 and A1A3, when selected supply 1.7525-
respectively. The pulse generator is triggered by an
megacycle (mc) and 1.7515-mc inputs to mixer
external audio signal generator connected to the PULSE
assembly A1A5. The output of the mixer assembly is
GENERATOR INPUT connector. The frequency of the
either 1.7525 mc or 1.7515 mc, or both, depending on
audio signal generator determines the pulse repetition
the position of two-tone selector switch A1S8. The
rate of the pulse generator.
output of the mixer assembly is connected to connector
h. When in the TUNE position, XMIT STATUS
J1. With common module tray A1A2 (fig. 68) connected
switch A1S5 supplies a ground to test set connector J1.
to the test set, the output of the mixer assembly can be
In the ON position, KEY switch A1S6 supplies a ground
switched from if. oscillator modules A1A2 and A1A3 to
and +20 volts dc to two pins of connector J1 and a
an external two-tone signal generator source by placing
ground to connector A1J4. The REC XMIT switch re-
Change 2
1-7
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