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STATIC MEASUREMENTS
Q1 BIAS
Connect your VOM to the circuit as shown in
Figure 43. Set your VOM to read 9 volts and
turn the power ON. The voltage at the base of
Q1 should be about 1.6 volts. If you do not get
this reading, check R1, R2, R3 and Q1. Turn
the power OFF.
ANTENNA FM ASSEMBLY
Antenna FM
2 Antenna Screws M2
3.5" Wire #22 Insulated
(extra wire in AM Section)
(see Figure O)
Mount the antenna to the PC board with two screws as
shown.
NOTE:
Some antennas have only one
threaded hole.
Cut a 2 1/4" wire and strip 1/4" of insulation off of both
ends of the remaining jumper wire. There are no holes
for the wire in this location, so tack solder the wire to the
pads as shown.
FM FINAL ALIGNMENTS
There are two procedures for the final alignment steps.
The first alignment procedure is for those who do not
have test equipment and the second is for those who do
have test equipment.
Your "magic wand" will be used to align the FM
oscillator circuit and the FM RF amplifier. When the
brass end of your "magic wand" is placed near the FM
oscillator coil L3, the coil reacts as if inductance has
been removed. Likewise, when the iron end of the
"magic wand" is placed near the coil L3, it reacts as if
inductance has been added. The same is true for the
RF coils L1 and L2. When the inductance of a resonant
Threaded Holes
Figure O
circuit is changed, the resonant frequency is changed
also.
When aligning the oscillator, changing the resonant
frequency changes the frequency of oscillation.
Likewise, when aligning the RF amp, changing the
resonant frequency at which it was selective.
When aligning the oscillator and RF circuits, coils L1
and L3 will be adjusted at the lower end of the band,
while the oscillator and RF trimmer capacitors are
adjusted at the higher end of the band. This is done so
that the RF amp tracks the oscillator properly.
-47-
COM
TP15
Figure 43
Solder
Jumper Wire
V
V
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