Detector Alignment - Elenco Electronics AM/FM-108TK Assembly And Instruction Manual

ALIGNMENT WITH NO TEST EQUIPMENT
With an alignment tool or screwdriver turn coils T1,
T2 and T3 fully counter-clockwise. DO NOT FORCE
IF ALIGNMENT
Amps COM
TP15
With an alignment tool or screwdriver turn coils T1, T2
and T3 fully counter-clockwise. DO NOT FORCE THE
COILS ANY FURTHER. Turn each coil in about 1 1/4
to 1 1/2 turns.
Use the earphone provided for best results. Switch to
the FM position. Connect your VOM to the circuit as
shown in Figure 44. Turn the radio ON and tune the
radio to a weak station. It is best to keep the volume at
a low level. Adjust T1 for the minimum voltage on your
VOM. Reduce the volume if necessary. Adjust T2 for
minimum voltage on your VOM and reduce the volume
control if necessary. Adjust T3 for minimum voltage on
your VOM and reduce the volume control if necessary.
As you adjust the coils you should hear less distortion
and noise. Repeat this procedure until the FM IF gain
is optimized. This process peaked the FM IF amplifier
to their maximum gain.

DETECTOR ALIGNMENT

Adjust T4 for minimum voltage on your VOM. Adjust T5
for minimum distortion. Repeat these 2 steps until the
ratio detector alignment is optimized.
OSCILLATOR ALIGNMENT
Tune the radio to a known station around 90MHz. Once
a station is found and its broadcast frequency is known,
rotate the dial until the white pointer is aligned with that
stations frequency on the dial. Using the "magic wand",
place the brass end near coil L3. Refer to Figure 45.
If the station is heard, this means that L3 needs less
inductance. Carefully pull apart L3 until the station is
heard. Place the iron end near L3. If the station is
V
V/Ω
THE COILS ANY FURTHER. Turn each coil in about
1 1/4 to 1 1/2 turns.
Figure 44
heard, this means that L3 needs more inductance.
Carefully press together L3 until the station is heard.
Pulling apart or pressing together L3 just a small
amount will have a great effect on the coils resonant
frequency. Repeat this step until the pointer is aligned
to the station's frequency. Tune the radio to a station
around 106MHz.
broadcast frequency is known, rotate the dial until the
white pointer is aligned with that station's frequency on
the dial. Place the brass end of the "magic wand" near
L3. If the station is heard, it means that L3 needs more
capacitance. Carefully adjust the FM oscillator trimmer
(as shown in Figure L, page 23), on the back of the gang
until the station is heard. Place the iron end of the
"magic wand" near L3. If the station is heard, it means
that L3 needs less capacitance. Carefully adjust the
FM oscillator trimmer located on the back of the gang
until the station is heard.
Spread apart the coil for less inductance
Press the coil together for more inductance
-48-
Battery
Once a station is found and its
"Magic Wand"
RF Coil
Figure 45