Super LED TV Backlight tester is a light source power supply that consist of isolating switch power supply , constants-current circuit , current control circuit and LED digital voltage display system.
1) Plug the power supply, Voltage shows around 156V(TD2B)and rising to around 300V(TD2B) after few seconds.
2) When testing, use the red and black pen to touch the anode and cathode of the LED ight respectively. The light will automatically change from slight brightness to high lightness gradually(3-5s) and then stabilize. The voltage display is the operating voltage of the light at that time.
Test method without disassembling the screen:
To lighting the screen must meet at least three requirements: A. backlight is on B. power supply to the screen C. signal supply to the screen. Otherwise, we cannot see the light from the screen or it is very dark.
(1) Unplug the interface sockets of the constant current plate and light bar.
(2) Insert the Red and Black pens of the tester into the anode and cathode of the interface of the LED light bar.
(3) Turn on the TV power supply and power the TV up normally(except for the constant current plate),at this time, if the light bar, LCD, main board and logic board all work normally, normal images can be seen from the screen. The brightness may be lower than the normal brightness of the original TV set. The output current of the tester shall adapt to the LED backlight bars of all sizes of TV sets, thus the brightness is relatively lower compared to the one -to-one constant current plate of the original TV set, which is a normal phenomenon.
1) For the TV has more than one groups of backlight, compare the voltages of each group, if the voltage difference more than 3V or 3%,it means the light bar has some problems.
2) For the TV only has one groups of backlight, it can also be compared with the good light bar of the same model, judging whether the light bar is good or not by comparing the voltage.
3) Testing the steady voltage value of the stabilivolt tube: connect the red pen with the cathode of the diode and the black pen with the anode, the voltage value displayed in the voltmeter is the steady voltage value of the stabilivolt tube.(the voltage error is normal within 5%)Control the testing time within 3S to avoid the severe heating of the stabilivolt tube of above 20v.
4) The voltage display should be around 300V(TD2B)in open circuit, if the voltage display not change when testing, it means the LED we test is in open circuit or the probes in poor contact.
5) When testing, the voltage displayed =00.0, indicating that the tested light bar or the lamp bead short-circuits, It also will display 00.0V when touch the two probes each other.
6) When testing the single LED beads, the voltage display lower than 2V and the LED beads not working, the electric leakage of the LED beads may exist.
7) When testing two subjects without electrical connection, if the voltage displayed is lower than the open circuit voltage, it indicates that there is electric leakage between the two subjects tested.