1. assembly
The TMP47C433AN and TC9020P used in this converter are CMOS integrated circuits and are more susceptible to damage. When soldering, check whether the soldering iron is leaking to avoid loss.
2. debugging
(1) Voltage Debugging The converter provides three sets of supply voltages. To test these three sets of power supply voltage, make them meet: 32 ± 1.5V; 12 ± 1V; 5 ± 0.5v.
When the TMP47C433AN and TC9020P are working normally, they must provide line and field sync pulses. To test the line, the amplitude of the field sync pulse should not be higher than 5v. Otherwise it will cause an abnormal operation.
(z) Image IF (38MHz) mid-week debugging using the sweeper to debug the middle week method, this article is omitted, the reader can refer to the relevant books. Only the debugging methods under amateur conditions are introduced here.
(b>Receive a local strong signal TV station to enable RFAGC to control, and use a multimeter to monitor the "AGC" terminal voltage of the ESC.
(3) Debugging used in AFT The debugging of AFT in the middle of the week is as follows:
(a) First note the 13-pin voltage VF of the TA7680 when the AFT is turned off, and turn the AFT on.
(b) Fine-tune this mid-week so that the AFT voltage is equal to vF.
(c) After the tuning is accurate, it must be confirmed that when the converter key FT+ is pressed, VAVr is decreased by the VF value and I is pressed by the converter key FT. VAF1 is increased by the VF value. When searching for TV signals, the VAFT variation range should satisfy: 2V ≤ VAFT ≤ 10V. At this point, AFT is well adjusted in the week.
(4) Adjusting the RFAGC delay amount Rotate the adjustable resistor clockwise to make noise appear on the screen. Rotate counterclockwise again, causing the noise to disappear and the image to be clear.
3. How to use The converter panel is equipped with a power switch, a power indicator, an infrared receiving window, and a keyboard. The rear panel has a power cord, an antenna jack, and an RF output jack.
(1) Connection method
(a) Antenna input The cable TV signal is connected to the antenna jack using a coaxial cable.
(b) RF output Use a coaxial cable to connect the RF output jack to the "RFIN" connector of the color TV.
(c) Plug the power plug into an AC outlet and turn on the power switch of the converter.
After completing the above connection, you can start operating the converter.
(2) the use of the keyboard
To automatically search for a program, follow these steps:
(b) Press the "AUTOMEMORY" button again and the converter will enter normal operation.
(c) Tune any channel preselector to be used by the television receiver to four channels: the band switch is dialed to the VL segment, and the preselected potentiometer is adjusted to the color power to receive a satisfactory image and accompanying sound.
Manual tuning can also be used if the signal from a TV station is considered to be inaccurately tuned by the above method. Manual fine adjustment is performed as follows:
(a) Press the "PROG" button and the converter enters the programming state.
(b) Use the "BAND" button to set the frequency band where the TV station is located.
(c) Press the "FINEUP" button to tune up, or press the "FINEDOWN" button to tune down until the tuning is satisfactory.
(d) Press the "MEMORY" button to store the adjusted TV station.
(e) Press the "PROG" button again and the converter will enter normal operation.
The selection of the station is carried out in the following two ways;
(a) Use the "CH+/CH-" button to sequentially recall the stored TV program up/down.
(b) You can also use the number keys on the remote control to switch to the channel you want to watch.
1 PCB Screw Terminal Block 2 Plug-in Terminal Block 3 PCB Spring Terminal Block 4 Barrier Terminal Block 5 Feed Through Terminal Block.
Terminal block consists of fixed terminal block (hereinafter referred to as socket) and free terminal block (hereinafter referred to as plug). The socket is fixed on the electric parts through its square (round) plate (welding method is also adopted for some), the plug is generally connected with the cable, and the plug and socket are connected by connecting nuts.
The terminal block consists of three basic units: shell, insulator and contact body.
Strictly speaking, terminal block refers to a solid device composed of an insulating base and more than one live part. Each conductive member can be used as a joint point for connecting two or more conductors (wires), and also as a tool for connecting or not connecting conductors (wires) individually. In the literal sense, the terminal block can be thought of as a wiring platform providing terminal or wire connection. The terminal block can be a combination type or a single-piece design. The combined terminal block is stacked in the way similar to the block combination, and the two ends are added with side covers and locked and fixed with screws. As for the single terminal block, the combination process mentioned above is not necessary, and it can be used alone.
Terminal Block Series
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