We are a Power Cord Manufacturers, and our products include 3 Pin Plug Power Cord, etc. Let me introduce to you how to repair the TV power strip.

　　TV Power Board Repair

　　1. No positive 5V voltage output. Analysis and maintenance: Check the standby power supply circuit and find that the voltage of IC1's ⑤-⑧ pins is 0 volts, and the welding part of the current limiting resistor RB13 terminal has been desoldered. It is recommended to replace the three current-limiting resistors RB1, RB2, and RB13 with resistors with the same resistance value of 1 watt or 2 watts to avoid damage again.

　　2. The voltage of positive 5 volts fluctuates around 3 volts. Analysis and maintenance: no-load test machine, the positive 5V voltage is still low, which indicates that the fault is in the standby power supply part. Check the Zener diodes DB4 (6.8 volts) and DB5 (20 volts) in the output voltage circuit, and find that DB5 is broken down, and the fault is eliminated after replacement. In addition, the Zener diodes DB5 (20 volts), DB10 (33 volts), and DB8 (10 volts) in this circuit are easily damaged, and the fault phenomenon mostly shows that the voltage of positive 5 volts fluctuates around positive 4 volts.

　　3. The output voltage of positive 5 volts is only positive 4 volts. Analysis and maintenance: no-load test machine, the positive 5V voltage is still low, which indicates that the fault is in the standby power supply part. Visual inspection found that the positive 5V filter capacitors CB7 and CB8 have been bulged, and the fault has been eliminated after replacement.

　　4. The positive 5 volts are normal, but there is no positive 12 volts and positive 24 volts output. Analysis and maintenance: The positive 5V standby voltage is normal, and the positive 5V voltage is connected to the power-on or standby control terminal with a wire. The voltage across the capacitor C5 is only positive 300V, which means that the PFC circuit is not working; measure the PFC oscillation block IC2 ( The voltage of pin 14 of the power supply terminal of L6563) is 0 volts (normal value is positive 19 volts), which is generated by the ④-⑤ windings of the transformer T2. Check the power supply circuit and find that the transistor Q11 is broken down and the resistor R7 is open. Test the machine after replacing the damaged components, and troubleshoot.

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