TCL color TV NT25C41 power supply red light flash does not boot troubleshooting - Home Appliances

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

Supply 3216 red light 1206 red light LED

MOS power IC full range

Shenzhen excellent micro led lamp bead manufacturers 5mm colorful flash short foot self-flashing bead LED

TCL color TV NT25C41 power supply red light flash does not boot fault troubleshooting phenomenon: press the power switch, the indicator light can not be turned on.
Repair process: There is no obvious short circuit in the measuring part, the main power is 300V, and the B+ voltage is 20-50V. In order to distinguish, the CPU power is swung below 2.5, and the standby control transistor is removed (this machine is standby buck), fault still. Disassemble the power supply current limiting resistor, B+ is connected to the dummy load, B+ voltage is 120V normal, the power supply itself is faulty, the fault is locked in the line part, the deflection is first pulled out, the short circuit line pushes the transformer output, the indicator light is still flashing, and the load is measured. Positive and negative 14V power supply), positive 14V obviously short circuit, habitually first 14V rectification (normal), the field block, +14V line is still short circuit state, the +14V filter has been short-circuited. Replace the filter, solder the field block, the line power supply current limiting resistor, thinking that the fault is eliminated, the test light can still flash.
Because the measuring tube C, E has no obvious short circuit, the short circuit pushes the output fault still exists, it is estimated that the high voltage package problem is not big, leaving the damping and line correction capacitor, etc., in the road test, the damping tube resistance value, feeling the damping reverse leakage After the change, the B+ voltage is 120V normal, the TV screen appears bright, and the standby control triode TV is normal on the insertion deflection welding.