Jetbeam C-LE 1xAA bulkhead mod

Since I recieved my JetBeam C-LE yesterday, I figured why not crack it open today! I have uncovered an "interesting" design "feature". :thinking: See the bulkhead photo.

Back of the Mini-star (gobs of thermal paste!)


Here too on the bulkhead!


Look at the depression in the bulkhead! That's the reason for the gobs of thermal compound! Black strip has been added to better show the depression. The bulkhead may have been designed for a Luxeon or Seoul Semi type of emitter. The star's heatsink only sits on the top of the ridge - not much contact area!


My fix (copper tab in the depression)


Added a brass battery contact as well so NiMH and Li-ion cells can reach better. I also installed a new foam ring.


Close-up of the knurling



If these are run with just 1.2-1.7V batteries, the bulkhead cavity should not pose a problem. However, if you plan on running Li-ions or split CRV2s, I would recommend filling the cavity in a similar manner to above to help transfer heat more quickly to the case.

I used a heat gun to heat the head and soften the glue.

Paul

Very interesting indeed.

Chimo,

I need to get mine open (it stopped working). Can you show a pic with the head parts separated. I want to make sure I understand where the two parts break apart.

Thanks.

I'm not seeing any pictures or links to pictures in the original posting. I've tried looking at it with both IE and Firefox with the same results. It sounds like other people are seeing pictures -- are you?

c_c

Curious_character said:

I'm not seeing any pictures or links to pictures in the original posting. I've tried looking at it with both IE and Firefox with the same results. It sounds like other people are seeing pictures -- are you?

c_c

Click to expand...

The pics are hosted on imageshack.com. Some people have problems accessing that particular website.

Monolith said:

Chimo,

I need to get mine open (it stopped working). Can you show a pic with the head parts separated. I want to make sure I understand where the two parts break apart.

Thanks.

Click to expand...

Here you go. It doesn't look like the board is potted. I tried a little pressure through one of the emitter wire holes but I didn't want to push too hard (I've only had it a day ).

chimo said:

Here you go. It doesn't look like the board is potted. I tried a little pressure through one of the emitter wire holes but I didn't want to push too hard (I've only had it a day).

Click to expand...

Thanks! I will do more than that as mine just up and died. So push pull twist anything to find out why it just quit. This is the second one that has been reported. No warning, no nothing. That almost seems like a bad component or a fragile electrical path. It has taught me one thing - never lube a working light...

If it ain't broke don't fix it =) I've gotten myself in lots of little binds b/c I ignored that lol. But sometimes it's good to fix non-broke stuff just to get it better. Ah, that's life.

Chimo, thanks for the inside look. Very interesting.

Monolith said:

The pics are hosted on imageshack.com. Some people have problems accessing that particular website.

Click to expand...

I found the problem -- the HTML text has the qualifier "target=blank" following the graphic file name, and this is causing my firewall to suppress the link for some reason. I need to fiddle my firewall settings.

(Edit: It was the "Banner/Skyscraper Ads" blocking. It's now off, and I can see the pictures. Thanks for the writeup and pictures -- I'm sure my JetBeam is going to get disassembled not long after it arrives -- if it ever gets here!)

c_c

I opened her up. The taking of the bezel apart was anticlimatic. I heated up the bezel with a hair dryer, got my rubber coated channel locks on the botton knurling, wrapped my strap wrench around the top and was prepared to wrench like there was no tomorrow - instead it just turned right off - you don't even need the wrenches, just something so you can hold the hot parts. I was a little disappointed......

Removed the Cree and measured about 65mV across the driver. LED tests fine. I can't figure out how to remove the driver. Is it pressed in? I did notice that if you look down the hole for the negative wire you can see what appears to be an adjustment screw. For what, I don't know. It takes a very small thin blade to turn it. Bottom line, now I have a Jetbeam that still doesn't work but is now in pieces but not enough pieces to get it fixed. It looks like major surgery to get the driver out. Anyone have any suggestions?

now i know why there is no stock for the jetbeam c-le...

it is very flawed!!!

Monolith said:

Removed the Cree and measured about 65mV across the driver. LED tests fine. I can't figure out how to remove the driver. Is it pressed in? I did notice that if you look down the hole for the negative wire you can see what appears to be an adjustment screw. For what, I don't know. It takes a very small thin blade to turn it. Bottom line, now I have a Jetbeam that still doesn't work but is now in pieces but not enough pieces to get it fixed. It looks like major surgery to get the driver out. Anyone have any suggestions?

Click to expand...

Okay, what's wrong with it? What does it do? I had one with a dirty neg contact that had real problems working in any reasonable fashion.

Try connecting a pair of batteries in series to the LED leads directly. Make sure it fires up. The 65mV seems really low.

I can't see an adjustment screw on mine. I wonder if it's a potentiometer...

Kevin

kevinm said:

Okay, what's wrong with it? What does it do? I had one with a dirty neg contact that had real problems working in any reasonable fashion.

Try connecting a pair of batteries in series to the LED leads directly. Make sure it fires up. The 65mV seems really low.

I can't see an adjustment screw on mine. I wonder if it's a potentiometer...

Kevin

Click to expand...

What's wrong is the LED does not light up with the driver. LED tests fine. Driver is only outputting 65mV - should be at least 3 - 3.5 volts. I suspect a component in the driver is bad. If it was possible to non-destructively get the driver out, I could see what was wrong with it. Right now it appears that I would destroy it trying to remove it. Is the adjustment screw a PWM adjustment?

Monolith said:

What's wrong is the LED does not light up with the driver. LED tests fine. Driver is only outputting 65mV - should be at least 3 - 3.5 volts. I suspect a component in the driver is bad. If it was possible to non-destructively get the driver out, I could see what was wrong with it. Right now it appears that I would destroy it trying to remove it. Is the adjustment screw a PWM adjustment?

Click to expand...

Ahhh, sorry; I misunderstood.

I don't know how to get the driver out. The two I got are almost perfect, and thus I am reluctant to do much in the way of removing components. That said, it does look like the LED could be removed and then the board pushed through through the two lead holes from the top. It looks like a press fit.

If it really is a small screw, I can't think what else it would be. I guess it could be one of the IC programming pins...

Did you get it from Emil? Is so, I bet a return would work.

Kevin

kevinm said:

Did you get it from Emil? Is so, I bet a return would work.

Kevin

Click to expand...

No, this was from CEJ's group buy. I've already given somewhat of a college try with pushing it out. I might have to grind off the lip to allow the board to come out.

Monolith said:

No, this was from CEJ's group buy. I've already given somewhat of a college try with pushing it out. I might have to grind off the lip to allow the board to come out.

Click to expand...

That's incouraging: one of mine has no lip. In fact, the board sits a small amount below the end of the head. Makes me think press fit even more.

It looks like a press-fit to me. The pcb seems to be in a thin brass ring (see my second last pic in the first post).

Paul

chimo said:

It looks like a press-fit to me. The pcb seems to be in a thin brass ring (see my second last pic in the first post).

Paul

Click to expand...

The issue is that the holes to stick something through limit the amount of surface area to apply the force. PC boards are not particularly robust. Also, there appears to be components under one of the holes, affecting the angle of thrust. In other words, mine is really press fit in good....

Monolith said:

The issue is that the holes to stick something through limit the amount of surface area to apply the force. PC boards are not particularly robust. Also, there appears to be components under one of the holes, affecting the angle of thrust. In other words, mine is really press fit in good....

Click to expand...

Agreed. I noticed a ceramic cap under one of the holes. If you do get it out - take lots of pics (that show the components well)! Cheers,

Paul

I had a question about this mod that I would like to share.

It was regarding the impact of the copper spacer with respect to using Li-ions.

This mod does nothing for protection of the driver circuit if it was not designed for Li-ions. It will help to keep the emitter cool, providing (perhaps) longer life and less output loss as the emitter should not get as warm.