Tandy Science Fair 28-207 User manual

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With your Crystal Radio Kit you can tune in the AM Radio Band
(550-1600 KHz) and you don’t use batteries or AC power. It works on
the same principle as the early Crystal Radio, however the crystal has
been replaced with a more modern device called a Diode. The function
of a Diode is basically the same as the old Crystal but with the
advantages of being smaller and easier to use.
CUSTOM MANUFACTURED FOR TANDY CORPORATION
Catalogue No. 28-207
CRYSTAL RADIO KIT

STEP BY STEP INSTRUCTIONS
PART NUMBER
Z-3152
CA-0619
C-4242
K-0669
HB-4804
- - -
E-0007
PARTS LIST
DESCRIPTION
Base Plastic
Cioil, Antenna
Tuning Capacitor
Knob for Tuning Capacitor
Spring Terminals
Diode
Earphone
DESCRIPTION
Red wire, short (50mm)
Red wire, long (70mm)
Black wire, short (60mm)
Black wire, long (110mm)
White wire short (70mm)
White wire, long (90mm)
PART NUMBER
- - -
- - -
- - -
- - -
- - -
- - -
DESCRIPTION
Green insulated wire
(for Antenna and Ground)
Screw, small & long (2.6 x 4mm)
Screw, small & short (2.6 x 3mm) (2)
Screw, medium (3 x 6mm)
Nut (3mm)
Antenna Coil Holder
PART NUMBER
W-1587
HD-2042
HD-2041
HD-2055
HD-7003
H-1535
Check each step as you complete it.
Check Parts List to become familiar with
each component.
Install the 11 Spring Terminals on the
Plastic Base - one at each large hole.
Do thei by pressing down rmly with the
point of a pencil and twist in place.
To connect wires to the Spring Terminals
bend the Spring over and insert the bare
wire end into the spring and release.
Mount Tuning Capacitor from the bottom of the Base and
secure with the two small, short screws. Mount Tuning Knob
with the small, long screw.
Connect leads from Tuning Capacitor to
terminals 12 and 13.
Do not cross leads.
2

Mount Antenna Coil on top of Base
with a medium screw and nut as
shown.
Connect wires from the Antenna Coil as follows:
Green lead to terminal 7
Yellow lead to terminal 2
Light Brown lead to terminal 4
Black lead to terminal 8
Look at the Diode. One end has a band around it - this is the
Cathode end. Mount the Diode between terminals 8 and 9, with
the Cathode end toward terminal 9.
NOTE: You can connect the Diode in either direction without
damaging it. Later on you might like to try the other
way (with Cathode to terminal 8) and see if it changes
reception.
Connect the short Red wire between terminals 4 and 12.
Connect the long Red wire between terminals 13 and 17.
Connect the short Black wire between terminals 3 and 7.
Connect the long Black wire between terminals 7 and 11.
Connect the short White wire between terminals 1 and 8.
Connect the long White wire between terminals 9 and 10.
Connect one Earphone wire to terminal 10, the other wire to
terminal 11.
Your Crystal Radio is ready to use. All you have to do is connect the
Antenna and Ground and listen in the Earphone
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ANTENNA AND GROUND HOOK-UP
This Kit includes a length of Green insulated wire for use as antenna
and ground wire. Cut off about 5 feet (150cm) of wire for grounding
your Radio. A radiator or cold water pipe makes a sutable ground. To
make a good ground connection, carefully remove about 6” (15 cm)
of insulation from one end of the wire. Scrape any paint or dirt from
the ground pipe until you can see bright metal, then wrap the bare
end of the wire arond the pipe several times and twist it securely.
Remove ¼” (7 mm) of insulation from the other end of the ground
wire and connect it to the ground terminal 3, (GND) of your Radio.
The remaining wire is your antenna. Remove ¼” (7 mm) of insulation
from one end and connect it to the Short ANTENNA terminal (1).
Then extend the Antenna to its full length and position for the best
reception.
This Antenna will be suitable if you live in a city, near several radio
stations. If you happen to live some distance from the nearest station,
a 35 to 75 foot (10 to 25 m) outside antenna may be needed. You
should connect this antenna to the Long ANTENNA terminal (2).
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UK: 29 GLEBELANDS, OXFORD, OX3 7EN
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