I. Name: Weight Snail WW818 type ultra -exterior seven -tube radio
2. Each component: See Figure 1 to Figure 5 in each component.
Figure 3. Print circuit board front
Figure 4. The back of the printing circuit board
Figure 5. Magnetic rods and coils, medium and Zhou, transformers, triode, resistance and capacitance
3. Reference materials:
The data attached to the kit include: 1. Pretending instructions, 2. Component list, 3. Print circuit board drawing and component related instructions, 4. Circuit schematic diagram, see Figure 6 to 8, respectively.
Figure 6. Preparation description and component list
Figure 7. Print circuit board and component description
Fourth, device and detection:
Figure 8. Circuit principle diagram
Before welding, check and measure each component to ensure that there are no problems, so as not to find faults on the printing circuit board and increase trouble. See Figure 9.
Figure 9. Before welding and printing circuit boards, the components should be given to inspection and measurement
Five, component installation steps:
For the general steps on welding components and printing circuit boards: first, small devices can be welded, such as resistance, capacitors, diode, triode; Transformer capacitance, potentiometer welded. See Figure 10 and Figure 11.
Figure 10. The component welding and printing circuit board are in progress
Figure 11. The component has all welded on the front diagram of the printing circuit board
6. Measurement and record of each current testing point:
Figure 12. Prepare for each test point to measure
The actual measurement results of each test point are as follows:
1. Open circuit current. At this time, there is no connection for each test point, but the 3V battery is connected.
2. Port-level current, Iv6v7 = 5.0mA (required value is 4-10mA)
3. Reappear current before low-frequency, IV5 = 3.7mA (required value is 2-4mA)
4. The secondary relegation current, IV3 = 1.0mA (the requirements value is 1-2mA)
5. The first mid-range relegation current, IV2 = 0.56mA (required value 0.4-0.8mA)
6. frequency-level current, IV1 = 0.28MA (required value 0.18-0.22ma)
7. After all the measurement points of the whole machine are short, the static current of the whole machine is measured, IO = 17.3mA.
Seven, simple adjustment after receiving the effect of radio stations:
FIG. 14. All print circuit board components are welded and installed in the case
In the case of being able to receive the Zhongbo Radio Station normally, you can find a radio station on the high -end, adjust the variable capacitance, and use the fine -tuning capacitor near the outer shell to make the sound the greatest; then find a radio station at the low end. At this time, adjust it The position of the coil on the magnetic rod makes the sound the greatest. In order to achieve the best results, you can adjust it several times. During the adjustment process, if there is no normal radio station in high -end or low -end, at this time, you can also use a continuous interference platform for debugging procedures.
Figure 15. After all the radios are installed, you can listen to the appearance map
After the radio DIY is completed, the video of the radio station is received and uploaded later. Interested friends, please pay attention.
8. Precautions in the DIY process:
The radio kit is reasonable, and the selection of components is superior. Therefore, as long as it is installed and welded correctly, it can be successfully assembled and can receive the radio station well.
There is a small episode on the circuit diagram here, that is, the output transformer on the circuit diagram is a self -coupling device; but in fact, this output transformer is the same as the input transformer, that is, there are primary and secondary coil respectively. Whether the kit is the case; fortunately, the structure of the output transformer of this kit is the same as that of the printing circuit board, and there will be no problem with installation and use. In Figure 16, it has been changed to the drawings. Please pay attention to your friends!
Figure 16. The circuit diagram of the actual measurement value of the output transformer and the actual measurement point of each test point