Okay, I got this light today, and started to check the ability of the light. Ez1000 xr-e, that's not bad, it can handle the overcurrent better, than ez900. Very foggy lens, I was unable to clean it with warm water+ soap and alcohol. So I polished it up with my dremel, now it's clean. Only this upgrade increased the throw capability with 4000lux. I measured with foggy lens 50kcd, with clean lens 54kcd. Tailcap current was 2A with a sanyo cell. But, what I noticed: the brightness instantly dropped very quickly. After 10sec the lux meter showed only 50kcd, another 10sec 45kcd...
and this is the reason:
Yes, that's a paper disk under the star. Heat transfer = almost zero.
So please be carefull, and check this on your light.
Only remove the paper disk will not work, because the led will be out of the focus.
I made a little metal disk for this, and now, after 20sec the the light still holds the 52-53kcd value.
I hope that is a one off item you have there. I have 4 now and none of them has had this. On one there was a paper disk above the led, between the plastic retainer disc and the led star. But only on that one unit.
BTW: Those lux values are spot on what I get with that light once the lens is cleaned.
Mine has a paper (I’d actually call it a soft cardboard) disc as well, with a hole in the center. The hole however has been filled in with thermal paste. Someone, somewhere, obviously felt that would do the trick, but the last thing you want to be doing is relying on a film of thermal paste to transfer heat, especially when you’ve created such a small thermal path in the first place. Thermal paste is for filling in the imperfections of two surfaces to be mated, not for creating primary thermal paths.
Was planning to rebuild/mod this light anyway, so it’s not a big deal for me. Waiting for a replacement reflector from DX as well, since the reflective coating was flaking off mine in more than one place, causing a nasty mess inside the head.
Thanks garrybunk for the quick response!
Our discoball light burnt out for tomorrows party and I figured the jacobs would give out a nice reflection from the ball, so i did a quick test… oh how right I was :party: party on
I put the 1 Mohm resistor mod on my Jacob - reset to high now in 2-3 secs when off. I used a surface mount, 800 series I believe - very simple to solder on. I also upgraded to the R2 LED - nice, little broghter, will be updating to a Nangj driver when it comes in.
Last week I had two A60, let’s call them #1 and #2.
The #1 had a tighter hotspot than #2 and pulled 2.15A rising fast to 2.4A.
That was a bad sign (could be a thermal problem and the road to self destruction).
Lumens measurement was 360 fading fast to 240!
The #2 pulled a steady 2.1A and was 350 lumens fading to 330.
I disassembled #1 at the LED end. The plastic capsule around the LED had previously been removed (there was pressed a hole in it) perhaps for adjustment?.
The cooling was castatrofal, the star sat loose on a 7mm black piedestal, 0.5mm high. I thought it was a piece of metal but it was two layers of self-adhesive plastic rounds meaning the star had no cooling at all!
There was some traces of white paste that could indicate that the star had previously sat directly, with paste, on the pill.
Now what is that?
What I don’t understand is why would someone put anything beneath the star unless it can’t reach the bottom of the reflector? For an optical adjustment I would put something between the star and the reflector.
Perhaps an answer will show when I clean up and mount the LED properly, without plastic in between and look at the hotspot. After all I have the #2 to compare to, the one with the bigger hotspot. Perhaps it too needs adjustment of the reflector position, in due time…
EDIT: Yep! After removing the plastic and mounting the star properly the hotspot grew the 10-20% to become the same size as the A60 #2 (and a bit uneven). I am now convinced that it is necessary to put 0.5 mm of metal beneath the star as the reflector cannot be moved closer to the LED. The factory must have had some ugly hotspots and made that quick and very dirty solution to the worst of them.
Also, without the spacer, the star is not pressed against the pill and overheating could be the result.
The one I played with at weekend had no “spacer” for want of a better word under the star, just the anodized light engine base (funnily enough, the keygos ke-5 has exactly the same set up, has a direct drive xm-l and I don’t remember seeing many threads about them burning out…).
I just sanded back the anodizing on both lights, new diamond thermal paste (because that’s what was available locally) and reinstalled the led’s.
If I’m honest, I’m unconvinced the anodizing causes that much issue, but what do I know?