VII ALIGNMENT INSTRUCTIONS
Alignment of the R-4A will require the following equipment.
1.
2.
3.
4.
5.
A reasonably stable signal generator having a frequency range
from 1.5 to 30.0
mc and variable output level.
An 11 megohm vacuum tube volt meter (VTVM)
A 12.6 mc series resonant crystal.
A WWV crystal for the WWV frequency most reliable in your
area ( see ” accessory frequency coverage”)
An alignment load consisting of a .005 mfd disk ceramic
capacitor in series with a 1000 ohm l/2 watt composition
resistor. Small alligator clips connected to each end would
be a great help.
6. Two 10K l/2 watt resistors and one 68 ohm resistor.
7. An accurate rule with l/32” divisions.
Before alignment is attempted, the R-4 should be turned on and allowed
to operate for at least one half hour.
A.
50 KC Oscillator Aliqnment
1.
Set the SSB/CW-AM switch to fast AVC.
2. Set Function switch to CAL.
3. Connect a 6” lead to your alignment load and connect it from
pin 5 of the 12BA6 (V5) to pin 5 of the crystal calibrator (V12).
4. Advance A.F. gain control so that an audio beat note can easily
be heard.
5. Adjust Tll for zero beat.
Note: Do not be concerned that 100 KC calibrator has not yet
been set. It cannot be “pulled” far enough off frequency
to be of any consequence for this purpose.
6. Remove alignment load.
B. 50 KC I. F. Aliqnment
1.
2.
3.
4.
5.
6.
Set the Passband selector lever to 4.8 KC and set the Passband
tuning knob to the middle of the longest line.
Attach the signal generator to pin 7 of V3 and adjust the frequency
to approximately 5645 KC. As 5645 KC is approached you should
hear a loud beat note in the speaker.
The generator frequency should
be adjusted for zero beat.
Adjust the generator output for an S meter reading of approximately
s - 9 .
Adjust T7 and Tl0 for maximum S meter reading. Note that
tuning of these cans will be quite broad.
Attach a VTVM to TP-1.
Adjust T14 for maximum positive voltage on VTVM (Do not remove
VTVM from TP- 1 yet)
.
