LED Tube Light Hacked. Home Utility Circuit 9

LED Tube lights are now commonly used to save energy. These are of different types ranging from 12 Watts to 100 Watts. The LED tube light has an LED panel powered by 12 volt LED Drivers. Each section of the panel consists of three 0.5 W White LED chip serially connected with a 20 Ohms (SMD No.200 ) current limiting resistor. Depending on the power output (Watts), the number of 3 LED sections increase. For example, in an 18 W LED Tube light, there will be 36 Chip LEDs (36 / 0.5 W = 18W). In 100 W LED Light, there will be two hundred 0.5 W LED chips. Two or more LED drivers are used to drive the LEDs. Sometimes the LED Tube light fails to light completely. The main reason is the failure of one or more LED driver. Let us see how to repair an LED Tube light.

LED Panel with Sections having Three 0.5 W LED Chips serially connected with a 20 Ohms resistor.

Defective LED Tube light. Two sections not lighting properly
Outer case of the LED Tube light removed
LED Tube light testing. Two sections of LED Chips not lighting well
Removed the LED drivers from the case
One LED Driver is damaged. New 12 V LED Driver used for replacement
New 12V LED Driver soldered
LED Tube light is now working properly. All LEDs light with full brightness
Sometimes even after replacing the LED Driver, some of the LEDs or a section may not work. There are two possibilities for this. The resistor may fail in one section or more sections.


The resistor is SMD type with value 200. It is 20 Ohms. De -solder it and connect a 22 ohms ordinary resistor. If the problem still exists, problem is with the LED chips. 0.5 W LED Chips are available, so replace with new LEDs.

3 responses to “LED Tube Light Hacked. Home Utility Circuit 9

  1. Dear Sir, I have Pharox T8 18W tube light. According to installation instructions only one end (on which L and N is written) to be connected power. However I connected erroneously wrong end to power. the tube light shot from the far end and is not working since. Please tell how to repair the same.

    • Open the case and remove the power supply. It may be an LED driver. Check its DC output using Multi meter. If it is ok then the power supply is working. Phase Neutral reversal normally will not affect because there is bridge rectifier inside. Then check the LED panel with separate 12 volt power .Usually there will be sets of 3 LEDs with a resistor. If one or more set is not lighting, then short the two working sets on either side of the non working set with wires. A Black hole is visible in damaged LEDs. By shorting the individual damaged LEDs, we can give continuity.

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