Heathkit SB-401 - CRYSTAL INSTALLATION

Page 96
Now load the Transmitter into a 50 Q dummy load for
maximum CW output. Refer to steps B through I on
Page 114.
Turn the Transmitter FUNCTION switch to SPOT.
Turn the Transmitter MODE switch to USB.
Turn the METER switch to ALC.
Set the Transmitter Zero Set Line directly under the
2-1/2 mark (center) of the slide rule dial.
Advance the MIC/CW LEVEL to the 12 o'clock
position.
Talk into the microphone and turn the Transmitter
LMO DIAL knob until your voice sounds clear and
normal in the Receiver.
Without
changing
the
circular
dial
setting,
remove
the
LMO
DIAL
knob.
Loosen
the
setscrew
on
the
circular
dial.
Hold
the
LMO
shaft
with
a screwdriver
through
the
front
panel
and
turn
the
circular
dial
until
the
“O”
iy
directly
behind
the
Zero
Set
Line.
Retighten
the
screw
in
the
circular
dial.
Replace the LMO DIAL knob on the LMO drive shaft.
Talk into the microphone and be sure the signal is
tuned in properly.
Switch the Receiver and Transmitter MODE switches
to LSB. Talk into the microphone. If the signal is not
the same as when all MODE switches were in USB,
adjust the LMO FREQ SHIFT coil of the Transmitter
until your voice is clear.
Set the MODE switches of both units back to USB. If
your voice is not clear, readjust the LMO DIAL of the
Transmitter until your voice is clear, and switch both
units back to the LSB mode. If the signal is not clear
adjust the LMO FREQ SHIFT coil. Repeat this
HHATHEIT
procedure until it is possible to go from the USB to
LSB mode without the sound of your voice being
changed (always switch both units simultaneously).
FINAL TRANSMITTER ADJUSTMENT
() Tune the Transmitter for maximum relative output
power into a 50 Q dummy load on the 3.5 band.
(_) Turn the METER switch to GRID.
NOTES:
2.
3.
cA
( )
( )
( )
In each of the following steps, set the LEVEL control
for approximately .2 milliampere indication on the
meter for the band being adjusted.
If the grid current indication will not come up as high
as .2 ma with the LEVEL control fully clockwise,
adjust the DRIVER and FINAL controls to increase
the current.
When adjusting the coils in the following steps, you ~
may obtain two voltage peaks. The correct peak is the
one when the slug is nearest the top of the coil.
Key the Transmitter and adjust the LEVEL control for -
a meter reading of .2 ma.
Adjust the Receiver 3.5 HET OSCILLATOR control |
for a peak meter reading. If necessary, keep the meter |
needle on scale with the LEVEL control.
Repeat the preceding two steps at each setting of the
BAND switches (except the Receiver 21.0 band).
Turn the FUNCTION switch to OFF.
This completes the alignment of the Transmitter. Refer to ;
the Final Assembly section on Page 103. i
ALIGNMENT WITH SBA-401-1 CRYSTAL
ACCESSORY KIT INSTALLED
CRYSTAL INSTALLATION
( ) Refer to the lettering on top of the chassis and install
the proper crystals in the eight crystal sockets. The
crystal frequency is stamped on the top of cach crystal.
( ) Refer to Figure 1-1 (fold-out from Page 86) and install
the 3396.4 kHz USB and 3393.6 kHz LSB crystals in
sockets Y9 and Y11 on the carrier generator shield. |