This situation is mainly caused by the following reasons: open circuit, short circuit phenomenon in the power supply, overvoltage, overcurrent protection circuit failure, auxiliary power supply failure, oscillation circuit does not work, power load is too heavy, high-frequency rectifier filter circuit rectifier diode breakdown, filter capacitor leakage and so on.
Interference in the power supply causes the control circuit to be unstable. Such as current sampling, voltage sampling circuit (comparator output) and so on. Check the circuit wiring, sensitive circuits to avoid interference sources, pairs of signals using wire (that is, as close as possible to the ground wireDistance parallel wiring).
The original was burned out by a short circuit. In the circuit, the current does not flow through the electrical appliance, directly connected to the two poles of the power supply, then the power short circuit. According to Ohm's law I=U/R, because the resistance of the wire is very small, the current on the circuit will be very large when the power supply is short circuited.
1, Hisense TLM3707 is an early LCD TV, more circuit boards.
2, To this problem I first provide you with a little power circuitRepair ideas, first repair, if not waiting for drawings. The answer to this question is as follows: ①, if the machine does not turn on the fault, first measure whether the voltage after the rectification filter is normal.
3, ①, to the Hisense LED32ec260jd power supply board on the ⅤD813 is: 1N4148W switching diode ②, to the VD812 is also: 1N4148W switching diode tube These two diodes are components in the power factor correction circuit.
4, this article focuses on introducing several maintenance examples of Hisense LCD TV, and hopes to repair the sea for everyoneTV helps.
5, the LCD TV switching power supply board seems to have two or three output terminals, one for the LCD screen lamp with one or two for the decoding board. There's another switch, the short switch power test. Test an output voltage first. No voltage in the electronic components, backwards to find the fault point.
should be a hardware hazard, although any electronic component has a limit of operating temperature, but unless you are in a place where the temperature is extremely low, generallyAbove minus 15 degrees should be no problem, see if there is a spot of welding.
Hello: ①, the normal typical value of 7 pin power supply to the 0B2269CP is 15V. The internal circuit of the chip is all started, and the entire power supply enters the normal working state. 2, the chip 8 pin no drive pulse output, the internal circuit of the chip may not work, so there is no output.
It may be that the question you ask is somewhat professional, or that others have not encountered or approached your question, so they can't help you. It is recommended that you go to the relevant forum of the problem to help, there are usually more people, alsoWill stop working.
2, switching power supply working principle STR-F6656 internal block diagram and pin function The internal block diagram of this thick film circuit is shown in Figure 1, including overvoltage protection, overheat protection, overcurrent detection and protection, protection signal latch, oscillation and charge and discharge resistance components, drive circuit and MOSFET power tube.
3, STR-G9656 adopts 5-end SIP insulation module package. Output 200V (standby), B power for 17V is the built-in power MOSFET and controller of FLYBACK type switching power supply with thickMembrane integrated circuit. It can work in QRC (quasi-resonant) and PRC (low-frequency turn-off time is certain, pulse width is controllable).
4, the principle of switching power supply circuit diagram Basic circuit diagram 2 Switching power supply circuit diagram The basic circuit diagram of switching power supply is shown in Figure 2.