1, pin voltage, 4 pin voltage should be correct, should be checkedThe next 3 pin level, if there is no feedback or the voltage is higher than 1V, may not be able to vibrate.
2, or 7 pin to ground regulator short circuit; There is voltage but high, change the 7-pin ground filter capacitor, 100UF/50V; There is voltage but the voltage is low and fluctuating, and the regulating circuit of 3842 is faulty.
3, if it is a stop vibration, you have to see if there is a short circuit phenomenon after the stage or see if your MOSFET sampling resistance selection is too large. If it doesn't work on its own, you can add DC15V voltage to pin 7 of 3842 alone, and see the output of pin 6 and other pin voltagesNo frequency is normal or not.
4, when the power supply is overloaded, 3842 protection action, so that the duty ratio is reduced, the output voltage is reduced, 3842 power supply voltage is also reduced, when the low 3842 can not work, the entire circuit is closed, and then rely on R1 to start the next startup process.
The P3482 on Skyworth LCD color TV is the power management integration block. A P3482 is an EUP3482.
I can substitute it directly with 1482. The pin functions of the TL3842P power management chip are as follows: ① the output end of the internal error amplifier; The foot is the reverse input end of the internal error amplifier; The RC network between the ① and ② feet is used to determine the gain and frequency of the amplifier; ③ The foot is the input end of overcurrent detection; ④ foot resistance capacitance timing element.
p component refers to a class of electronic components with p marking components, usually refers to the amplifier or switching characteristics of the diode, transistor or field effect tube. p refers to positive materials, corresponding to N-type materials.
Whatever kind of power supply it'sNo residual image technology to achieve a good look.
Skyworth 42k08rd is a 42-inch HD LCD TV. To judge what chip it uses, it can be speculated from three aspects. First, it is possible to analyze which chip is used by the function and performance of the TV.
2, the reasons are as follows: because UC3842 (KA3842) operating voltage and output power are very different from UC3843 (KA3843).
3, first check whether the reference voltage of pin 8 of the 3842 chip is 5V, if it is lower than or no 5V voltage, it should be further checked whether the IC1 foot has 10V ~ 18V voltage. If not, check R2 and rectification circuitAnd if D7, R10 is faulty check the components around IC1 and T2.
4, A. ⑦ Pin: power input. The starting voltage can not be lower than 16 v, if the supply voltage is lower than 10 V after starting, automatically turn off the ⑥ pin modulation pulse output to achieve undervoltage protection. The power input terminal is connected with a 36 V voltage regulator tube to prevent the chip from being damaged when the input voltage is too high. ⑧ Pin: 5 V reference voltage output end.
5, the 2 pin of the KA3842 is the inverting input of the error amplifier, which is usually connected by a resistance voltage division and a switching power supply. KA384Pin 5 of 2 is the ground terminal, and there should be a fixed resistance between it and pin 2. If the divider resistance measurement of disconnect pin 2 to the ground is straight through, it may be the internal damage of the KA3842.
p3482. P3484 power chip and p3482 power chip belong to the same type of chip can be replaced. Power Management Integrated Circuits (Power Management Integrated Circuits) are used in electricityA chip in a sub-device system that performs the conversion, distribution, detection, and other functions of power management.
TL3842P can be replaced by UC3482 or KA3842A.
Fault code: P3482 The fault code is Cylinder 11 Deactivation System/Intake Valve Control - Performance problem. Specifically, there is a problem with cylinder 11 deactivation/intake valve control performance. The fault falls into the cylinder stop category.
Check whether the power supply of the power chip of the p3482 Skyworth chip is normal, and then see whether the control voltage required for output to the field tube is normalIf not, most chips are broken. If the power chip is not changed, it is necessary to check the voltage of the CPU VID0~4.
TOP224 TOP225 TOP226 TOP227 These four can be replaced.
Because the volume of 15F/400V electrolytic capacitor is basically the same as that of 10F/400V electrolytic capacitor, there will be no installation problems, so it can be replaced. When replacing, it is necessary to note that the cause of the original capacitor damage is analyzed first, and then replaced.
1. The circuit schematic diagram is shown in Figure 2. As shown in Figure 2, AC is low-pass filtered by C1LC15 and C1C13, in which C1C15 forms an anti-serial-mode interference circuit for suppressing normal noise. C1C1L1 consists of anti-common-mode interference circuit, which is used to suppress common-mode noise interference.
2, UC3842 is a PWM control chip, often used in switching power supply control circuit. The working principle is as follows: The controller receives feedback signals: In the switching power supply, it usually passes electricityComponents such as sensors and capacitors form a feedback loop that feeds information about the output voltage or current back to the controller.
3, 4. Application circuit Figure 4-6: Flyback switching power supply controlled by UC3842 This is a flyback switching power supply schematic, the control chip is UC3842. There are three output voltage levels for this power supply: 5VDC, 12VDC, and -12VDC. The circuit converter is also a buck type hard switching circuit.
4, boot moment, rectified DC voltage through R2 to chip 7 pin power supply. Once the circuit vibrates, the original side of the transformer TThe high frequency driving current is generated in the coil N1, and the high frequency voltage induced in the secondary coil Nc is rectified by VD2 to maintain the power supply of UC3842.
5, the circuit is mainly composed of bridge rectifier circuit, high-frequency transformer, MOS power tube and current type pulse width modulation chip UC3842.