Elenco SEE AMFM108CK - Manual (Page 27)

-26-
AM FINAL ALIGNMENTS
There are two different AM alignment procedures.
The first alignment procedure is for those who do not
have test equipment and the second is for those who
do have test equipment.
Included in your kit is a special device called a
“magic wand” which is used for aligning resonant
circuits. It usually has a piece of brass on one end
and a piece of iron on the other. When the brass end
of the “magic wand” is placed near the AM antenna,
the antenna coil will react as if inductance has been
removed. Likewise, when the iron end of the “magic
wand” is placed near the AM antenna, the antenna
coil will react as if inductance has been added.
Therefore, when either brass or iron is placed near
the antenna coil, it will change the inductance of the
antenna coil. This change in the inductance will
cause the resonant frequency of the circuit to
change, thus changing the frequency at which the
antenna was selective. When aligning the antenna
and oscillator circuits, coils L4 and L5 are adjusted at
the lower end of the band, while the oscillator and
antenna trimmer capacitors are adjusted at the
higher end of the band. This is done so that the
antenna and the oscillator will track correctly.
AM ALIGNMENT WITHOUT TEST
EQUIPMENT
It is best to use an earphone for this procedure.
Make sure that the switch is in the AM position. With
an alignment tool or screwdriver, turn coils L5, T6, T7
and T8 fully counter clockwise until they stop. DO
NOT FORCE THE COILS ANY FURTHER. Turn
each coil in about 1 1/4 to 1 1/2 turns. Set the AM
antenna coil about 1/8” from the end of its ferrite rod.
Refer to Figure K.
IF ALIGNMENT
Turn the power ON and adjust the volume to a
comfortable level. Turn the dial until a weak station is
heard. If no stations are present, slide the antenna
back and forth on its ferrite core, and retune the dial
if necessary. Adjust T6 until the station is at its
loudest. Reduce the volume if necessary. Adjust T7
until the station is at its loudest and reduce the
volume if necessary. Adjust T8 until the station is at
its loudest and reduce the volume if necessary.
Retune the radio for another weak station and repeat
this procedure until there is no more improvement
noticed on the weakest possible station. This
process peaks the IF amplifiers to their maximum
gain.
OSCILLATOR ALIGNMENT
Tune the radio until a known AM station around
600kHz is heard. It may be necessary to listen to the
station until their broadcast frequency is announced.
If no stations are present at the low side of the AM
band, adjust L5 until a station is heard. Once a
station is found and its broadcast frequency is
known, rotate the dial until the white pointer is
aligned to that station’s frequency marking on the
dial. Adjust L5 until the station is heard. Tune the
radio until a known station around 1400kHz is heard.
It may be necessary to listen to the station until their
broadcast frequency is announced. If no stations are
present, adjust the AM oscillator trimmer on the gang
until a station is heard (refer to Figure L). Once a
station is found and its broadcast frequency is
known, rotate the dial until the white pointer is
aligned to that station’s frequency marking on the
dial. Adjust the AM oscillator trimmer on the gang
until the station is heard. Repeat these 2 steps until
the oscillator alignment is optimized. This process
sets the oscillator range at 955kHz to 2055kHz.
Magic Wand Assembly
Place the piece of brass inside the end of the
shrink tubing, with 1/4” outside. Heat the brass up
with your soldering iron until the tubing shrinks
around the brass. Assemble the iron piece to the
other end in the same manner.
Soldering Iron Tip
Shrink Tubing
Iron Slug
Brass Slug