The repair of the CRT TV is nearing the end, and the high-voltage package is a wearing part. It is inevitable that sometimes the accessories will not be available. However, sometimes it is a pity to give up. As long as it is daring, the heart is fine, and the high-pressure package is not a modification. It is difficult to reproduce the glory of the old color TV. Temperature And Humidity Sensor The temperature and humidity sensors mostly use the temperature and humidity integrated probe as the temperature measuring element to collect the temperature and humidity signals, which are converted into current signals or voltage signals that have a linear relationship with temperature and humidity after being processed by circuits such as voltage stabilizing filter, operation amplification, nonlinear correction, V / I conversion, constant current and reverse protection, It can also output 485 or 232 interfaces directly through the main control chip. Temperature And Humidity Sensor,Dry Cell Temperature And Humidity Sensor,Humidity And Temperature Sensor,Industrial Humidity And Temperature Sensor Taizhou Jiabo Instrument Technology Co., Ltd. , https://www.jbcbyq.com
First, the role of the high pressure package.
The high voltage package, the name is the line output transformer, some people call the line package or line change, the main role of the CRT TV is to generate the anode high voltage, and provide the focus, acceleration, G1 and other voltages. Note that the energy provider of the deflection current is not a high voltage package, but an S correction capacitor. When the line tube is turned off, the B+ voltage charges the S capacitor through the high voltage package and the deflection coil, and the current is only passed through the high voltage package. Because the high voltage package works in the state of high temperature, high frequency, high voltage and large current, and the external environment is wet or dusty, the probability of damage to the high voltage package is high.
Second, the lesion causing damage to the high pressure package.
1. Breakdown of high voltage filter capacitor in the package.
2. Short circuit between the high voltage coils in the package.
3. Leakage or breakdown of the high voltage silicon reactor in the package.
4, the primary secondary coil short circuit in the package
5. The aging component of the package is aging, making the focus and acceleration voltage unstable.
6. The insulation performance of the package is reduced, so that the high voltage package is fired inside or outside.
Third, the keywords related to the high voltage package.
1, HV - anode high voltage. The HV voltage varies depending on the size of the picture tube. Typical HV values ​​are 23KV to 29KV.
2, FV - focus voltage, sometimes called G4. The FV voltage is usually obtained by a resistor potentiometer in the HV terminal, and the voltage value is 3KV to 10KV. If it is double-focus, it is divided into FV1 and FV2. In fact, there is a set of potentiometers inside.
3, SV - acceleration pole voltage, also known as G2. The SV/G2 voltage is also obtained from the HV terminal voltage division, and its voltage value is 150V to 1000V.
4, AFC - line reverse pulse. The original meaning of AFC is automatic frequency control. The synchronization signal sent to the scan chip, the line detection signal required by the CPU, and the line pulse required by the OSD menu are all referred to as AFC. The AFC sampling can be outputted in the winding of the high voltage package, or it can be obtained by using the divided voltage in the C pole of the row tube, and the latter has a high failure rate.
5, ABL - automatic brightness control. The ABL terminal is always connected to the cold end of the high voltage winding to detect the current of the HV. When the brightness is too large, the HV current must increase. When the ABL circuit detects this condition, the response can be limited to increase the brightness. It is recommended that the maintenance personnel be equipped with a 100K resistance range multimeter (MF10 type) or a megohmmeter to measure the resistance of the ABL end to the HV cap to determine whether the high voltage silicon stack has a short circuit or leakage; and to measure whether the high voltage capacitor inside the package is leaking. Note that the 10K resistor range cannot measure high voltage silicon stacks and high voltage capacitors.
6. Primary and secondary windings - the primary coil is connected to the B+ input and the end of the high voltage package, and the other is the secondary coil. The primary coil has a large number of turns, and the probability of failure is very small; while the secondary high-voltage package has a very small wire diameter and a large number of turns, it is prone to a turn-to-turn short circuit.
7. Inductance - The inductive reactance generated by the AC current through the coil is the inductance. For DC power, the impedance of the coil is zero (ignoring the resistivity of the wire itself), but for high-frequency signals, the inductance of three turns is also large. The unit of inductance is ML (millihen).
8. Forward and reverse (simplified) When the line is turned on, it is the scan forward, and when it is off, it is the scan reverse. Both have a current through the high voltage package (the energy is stored in the high voltage package in the forward direction and the energy is released in the reverse direction).
9. Forward and reverse rectification - Since the peaks of the forward and reverse strokes differ by 8 to 10 times, a winding adopts different rectification modes, and the generated voltage values ​​are also 8 to 10 times different. The forward rectification voltage is low but the current is large; the reverse rectification voltage is high and the current is small, but the output power of both is the same.
10, the polarity of the winding - because the scan forward and reverse peaks are different, the output of the winding must distinguish between positive and negative. If the high voltage package does not need to be changed, the polarity of the winding is determined by the manufacturer in the pin; if the coil is to be wound in the core, the polarity cannot be ignored. For example, in a circle around the core, the high voltage package pin is facing downward, and the core is facing the user. The left end of the line is the positive end and the right end is the negative end. The negative terminal is grounded, and the positive terminal is connected to positive rectification to obtain about 10V voltage, and the negative rectification can be used to obtain -3V voltage; the positive terminal is grounded, and the negative terminal is connected to positive rectification to obtain 3V voltage, and negative rectification can be performed. Get a voltage of -10V. Everyone must understand the above clearly, and it will be handy when adding coils. Note that high voltages are low currents and vice versa. The above voltage parameters will vary depending on the circuit design, but the specific difference is not too large, and can be used as a reference when estimating the voltage of the winding.
11, like the field power supply, AFC, when the voltage is not suitable for the discharge, can be solved by the core self-winding coil, for example, when the replacement of the high voltage package 180v visual display is not available, (the original machine has) can be less The circle, (such as 5 turns) is connected to the +B power supply at one end, and the other end is connected to the view-out rectifier tube to measure whether the voltage is suitable. If the voltage is too high, the terminals at both ends of the winding are exchanged, and then the number of winding turns is adjusted.
12, pay attention to the pin function, some have to cut off the copper foil wire of the circuit board, re-connect with the wire, be sure to check the correct, and then power on the test machine.
Upload some common high voltage package data below: High pressure package information.pdf