TABLE I - AM ALIGNMENT CHART (See Figure 7)
NOTE: Set Selector Switch to AM
Step
Band & Dial Generator
Setting Frequency
Signal
Input
Indicator and
Connection
Adjustment and Indication
1 Indicator at Ex-
455 kHz 30%, AM Mod Through .05 MFD DC VTVM at TP-, Adjust T2 and T3 for maxi-
treme left end of at 400 Hz. Generator capacitor to TP-22,
2, terminal 2 of mum indication on meter. As
dial output level 5µV,
terminal 22 of Al.
Al.
a gain check, input should be
maximum less than 4µV for an. output
0.5 vdc above noise.
2 AM at 600 kHz
600 kHz, 30% AM Mod AM EXTERNAL Oscilloscope and Adjust Tl and Ant Coil L103
at 400 Hz. Generator ANT. and GND. dc VTM at TP-2, for maximum indication on
output level 1 mV,
terminal 2 of Al. meter. Keep dc output level
maximum. below 1 volt by reducing in-
put as peak is approached.
3 AM at 1400 kHz
1400 kHz, 30% AM Mod Same as Step 2, Same as Step 2, Adjust (first) AM OSC TRIM,
at 400 Hz. Generator o above. above. (then) AM ANT TRIM for
output level 5 0 0 µ V ,
maximum indication on meter.
maximum. Keep dc output level below 1
volt by reducing input as peak
is approached.
4 Repeat steps 2 and 3, above until all outputs are peaked at the proper frequencies. As a gain
check, 600 kHz input should be less than 3OµV for output of 0.5 vdc above noise, and 1400
kHz input should be less than 35µV for output of 0.5 vdc above noise.
TABLE II - FM ALIGNMENT CHART (See Figure 7)
Set FM MUTE Switch to OUT (button out), and Selector Switch to FM (button in).
Generator Signal Input Indicator &
Adjustment and indication
Point Connection
Check color code (paint dot) on ceramic filters FL1 and FL2 (figure 2) to determine IF center
frequency. Frequency for each color is: Green (10.60), Black (10.65), Blue (10.67), Red (10.70).
Orange (10.73), White (10.75), Yellow (10.80). Both filters in any one receiver must have same
colored dots.
2 FM at 98 MHz 98 MHz ±300 kHz sweep FM 300 ohm an-
O s c i l l o s c o p e a t Adjust T4 and FM IF XFMR
deviation at 400 Hz mod-
tenna terminals TP-6, terminal 6 of (in tuner) for max gain with
ulation. Generator out-
through dummy Al. good symmetry. Adjust T5
put level approx. 2OµV.
antenna (see fig-
for optimum “S” curve.
gure 6)
3 FM at 104 MHz
1 0 4 M H z ±75 kHz
Same as Step 2, Tuning Meter Check tracking. If necessary,
sweep deviation at 400 above adjust FM OSC TRIM, FM
Hz modulation. Genera-
RF TRIM and FM ANT TRIM
tor output level approx. for max gain.
lOµV.
4 FM at 90 MHz 90 MHz µ75 kHz sweep Same as Step 2, Tuning Meter Check tracking. If necessary,
deviation at 400 Hz mod-
adjust FM OSC COIL, FM RF
ulation Generator out-
COIL and FM ANT COIL for
put level approx. 1OµV.
max gain. FM OSC COIL is
adjusted by carefully compres-
sing turns closer together with
an
insulated
instrument.
NOTE: Repeat steps 3 and 4 as required to obtain satisfactory tracking at both frequencies.
FM MUTING CHECK
5
FM at 98 MHz 98 MHz ±75 kHz sweep Same as Step 2, a c V T V M a n d Record ac output level on
deviation at 400 Hz. above scope a t T P - 8 , VTVM
Generator output level terminal 8 of Al.
20µV.
6 Same as Step 5, Same as Step 5, above. Same as Step 2, Same as Step 5, Depress FM MUTE switch.
above. above. above. Reading at TP-8 should drop
about 3 db. If required, adjust
MUTE ADJ (R90) for proper
reading.
6
