Good , i want to use a resistor instead of them , wich value and wattage of resistor ?You might find it easier to remove the wire leads, then put the circuit board (which is most like a metal core board) on a hotplate and gently heat it up until the LEDs that need to come off get loose. Either that, or get a higher power soldering iron -in either case you will have to heat the circuit board to the point the solder starts to melt.
What does this mean? Did you apply 5V to each LED? If so, all of them should have burned out.after test all leds with 5v
Unless the 5 volts was not an ideal voltage source.What does this mean? Did you apply 5V to each LED? If so, all of them should have burned out.
Yes i test them with 5v the supply voltage is about 400 VWhat does this mean? Did you apply 5V to each LED? If so, all of them should have burned out.
For the viltage is about 400 V to supply 70 leds , i try a 68 ohm 1W resistor but any leds workUnless the 5 volts was not an ideal voltage source.
Figuring out what resistors to use is quite a puzzle. Can you find out how much current is going through the LEDs and the typical voltage across one of the LEDs?
A better solution would be to wait for an identical lamp to stop working and then combine working parts to make one whole lamp.