2 - Component Placement
3 - Color Code and Part details
Diagram for Resistor Values
9013
9018
BWN
ORG
GRY
GRN
BLK
RED
PUR
YEL
WHT
BLU
GLD SIL
Digit
Digit Number of 0
% Tolerance
Orange (3)
Black (0)
Orange: (3 zeros)
Gold for 5% tolerance
Means: 30 K
W
Symbol:
Actual shape:
Short
Long
Symbol:
Actual shape:
Diagram for Resistor Values
Magnetic Rod Coil wiring
Diagram for Ceramic Capacitors
Wound
100 Tr
Wound
10 Tr
Here means: 22000 pF = 0.022
m
F
First 2 digits for the Capacitance (pF),
Third digit for the number of zeros.
Diagram for Electrolytic Capacitors
Transistor
Pin Diagram
e = Emitter
b = Base
c = Collector
S66E
Six transistor superheterodyne radio teaching kit
中夏牌
1- Assembly Instructions
Change Notice: The earphone socket used in the original S66D has been modified as requested by teachers and students. Our factory has
changed the original socket to a stereo one. The earphone socket and the electrical schematic have not changed, but the wiring has been adjusted, and
the version renamed S66E. The modified radio has higher sensitivity, louder sound and universal use of any small earphones such as MP3 or similar.
Teachers and students, please pay attention to this during the assembly process. Please forgive us for the inconvenience caused by this modification!
Z
hong
X
ia Co.
The circuit used in this
3V low voltage fully transistorized super-heterodyne
radio is provided with installation and debugging instructions. It has the advantages
of stable operation, loud sound, and low power consumption. It consists of an input stage
with a high-level mixer, two-stages of Intermediate Frequency with detection level and AGC,
low-level audio and power amplifier stage. The frequency ranges from 535 kHz to 1605 kHz
in the Medium Waves band. The design of this circuit and the selection of the component
was made by and approved by Radio professional engineers. In addition to further learning
electronic technology during the assembly process, you can also master the electronic
measurement and debugging technology, and you can do it in one fell swoop. Please read
this instruction carefully before assembly, and it will be a great help for your own understanding.
educative
.
2. Installation process requirements: Before you take the soldering iron, please use a multimeter to check each component, so that you know what
you will install. Please start with low-profile and heat-resistant components first (such as resistors), then continue with larger components (such as
IF transformers), and finally install components that are fragile (such as transistors). 1 Resistor installation: please read the resistor value (referring
to the color code explained in this manual.) After verifying the distance between the two holes, bend the resistor after you decided to mount it
horizontally or vertically on the circuit board. The height must be uniform. 2 The length of the ceramic capacitor and the transistor leg cutting should
be moderate. Do not cut too short, and do not stay too long. They should not exceed the height of the middle circumference. The electrolytic capacitor
should be placed vertically and very close to the surface of the circuit board. Too high will affect the installation of the back cover. 3 The magnetic rod
coil (T1) is made of insulated self-welding wire, can be scraped with a knife or sandpaper. The four rod coil leads can be directly plated with a soldering
iron and rosin core soldering wire to the circuit board copper pads. 4 After the double variable tuning capacitor is installed close to the board, the upper
part of the component in its circumference is cut with a diagonal pliers before soldering. In order to avoid obstacles during installation or tuning, please
trim the components that may affect the dial tuning (cut T2 and T4 pins and grounding lugs, double connected three lead pins, potentiometer switch legs.
5 Installation of the earphone socket: The welding speed should be fast, not to burn the plastic part of the socket and cause poor contact. 6 Installation
of the LED: Please first install the LED on the circuit board, then mount it on the plastic casing, and align the LED body with the casing hole before
soldering it. 7 After the speaker is placed in its recess, the soldering iron will be used to melt the plastic: First press the horn to prevent it from loosening
later, then sink the surrounding three plastic pillars on the edge of the horn.
is the oscillating coil of the Mixer, T3 (White) is used in the first IF stage, and T4 (Black) in used in the second IF stage. These three IF transformers have
been adjusted to the specified frequency before leaving the factory. They may only need a fine-tuning after installation, so please do not attempt to adjust
too much. In addition to shielding, the metal IF transformers casing also act as ground return path, so the metal shielding must be reliably grounded. 2
T5 is the audio transformer driver, iron core. The bump mark on the frame is the primary, and the printed board also has the dot mark. The wiring diagram
can be clearly seen on the printed board. Do not install it reversed (you can also check the orientation with a multimeter). 3 VT5, VT6 (marked 9013)
are medium power transistors. Please do not confuse with VT1 - VT4 high frequency low power transistors because their shape and position are the same.
VT1-VT3 are marked 9018, VT4 is marked 9014, please don't install them wrongly. 4 The component parameters and values are referenced in the
electrical schematic. If there is any discrepancy with the actual component parameters, please be flexible.
1. Part description: 1 The Intermediate Frequency transformers (hereafter referred to as IF) are
provided in one set. Please refer to the wiring diagram and the printed board diagram. T2 (Red)
4. The quality of this Kit is guaranteed for 3 months. If there is a problem with the quality of the components, as long as you do not cut the feet, burn
the plastic, or damage the appearance, they can be returned to our factory for free replacement.
3, Debugging: With the Potentiometer switch turned off, and the battery installed, connect the multi-meter (using the 50mA range) in parallel with the switch
terminals (ammeter acting as a closed switch). Check that the drained current is less than 10 mA, so you could now turn on the potentiometer switch.
Continuous currents: use the multi-meter to check the 4 x Transistor currents through the gaps in order: D,C,B,A. If the values are correct (Please refer to
the schematic), you could now solder the 4 x gaps. Turn the volume to maximum and adjust the dual dial to receive the radio. Arrange to bury the speaker
wires and battery wires in a relatively hidden location before installing the board, but the wires should not affect the rotation of the tuning dial and should
avoid the screw column. After the circuit board is installed, screw it. The radio is now complete. If the measurements are not around the specified current
values, please check the polarity of the transistors carefully. Check if any mistake on the IF or Audio transformers? Also check for false or mis-soldering, etc.,
if the measurement of a particular circuit is not normal, it indicates that there is a problem at that circuit portion. Due to this user manual limitation, please
refer to relevant literature for the working principle, adjustment of intermediate frequency, adjustment of frequency range…
We believe that by assembling this teaching receiver produced by our factory, you will definitely acquire a lot of new knowledge.
RED
WHITE
BLACK
DOT
