I found an led lamp at Ikea that I liked with a nice long flexible neck and a nice heavy base, but when I got it home I found the colour temperature was a little warm for me and it had a yellowish tint. I think it would be fine for some applications, but it didn’t match any other lighting in the room or my other desk lamp so it was going to bother me until I changed it. Sorry I didn’t take many pictures as I went, but it should still be enough to show you what I did.
Finished mod with beam shot.
Here’s the original “star”. It’s just a small fibreglass pcb with some 7135’s. There isn’t a very good thermal path from the led to the body of the lamp. As you’ve probably realized by now, you could run this directly off a lithium cell. It could make an interesting work light.
I had some Nichia 119’s from fasttech https://www.fasttech.com/p/1325116 , but fasttech didn’t have any stars that fit so I had to use a general purpose star with a slight modification https://www.fasttech.com/p/1133804 I sliced a V groove through the center pad to separate it in two, for the positive and negative terminals of the nichia 119. I used some solder paste and a hotplate to reflow the led, some wire and some 7135’s to the star. It’s not pretty but it does the job. You can’t solder the wires to the proper pads, or they’ll get in the way of the reflector
The new star.
Underneath. The original star had enough thermal paste, so I didn’t add any.
The 7135’s get in the way of the reflector so you have to file or melt part of it away. The new star is also thicker so you must shave the bottom of the reflector down, or the lens and lens retainer will stick out and leak light out the sides, which looks a little ugly.
Reflector mounted in place. The reflector holds the star down and is screwed to the metal body of the head of the lamp. As you can see, the dome on the led is not centred over the die, but it doesn’t affect the beam here.
The lens is held in place by the retainer which clips onto the reflector. You have to pry the retainer out to take the head apart in the first place.
I find the nichia to be a much nicer tint and the light is pretty much perfect for getting light exactly where you need it for soldering or detail work.