Huh, my led fell off, now what? RC-G2 now has Q5 instead of P2.

Well, I have to say this is a first for me. I took the reflector off of my Rom G2 today and the emitter just fell right out! The round board is still in place of course. Can I just glue the P2 back onto the board? Would Fuji heatsink glue do? Artic Alumina? Please don't tell me I have to attempt to reflow solder it

Of course, probably a good time for a Q5, but either way, why waste a perfectly good P2.

Suggestions?

Re: Huh, my led fell off, now what?

How was it connected electrically? Is it hanging by its wires or something? If so, you can just AA it back on.

Re: Huh, my led fell off, now what?

If the square plate under the lens came off, then solder is the only way to do it....

Re: Huh, my led fell off, now what?

If you love this light, get a Q5!

Re: Huh, my led fell off, now what?

Did the whole emitter fall out or did the dome fall out?

Re: Huh, my led fell off, now what?

The emitter (the square part) fell off of the heatsink (the round white PCB part that would be a star if it was star shaped) . Just a few inches to my desk, no damage. But I have never seen that before. It wasn't soldered. It looks like some sort of silvery gray heatsink compound, though not enough. I will more than likely not re-use it in this light, but like I said I should salvage it for something else, maybe a fixed lighting project. So, which glue do I need to use and how carefull do I need to be about it touching the little round through holes that are actually the conductors? I was surprised the only thing making electrical contact was pressure, it seems if you didn't get it on very tight you could lose some current through that connection.

I have watched the you tube video of reflow soldering, but he is removing an emitter from a star, not installing one. So, even though I will be gluing it, if theoreticly I was going to solder it, how do you not short out the two holes at the bottom?

*Edit* One more question. The slug isn't considered electricaly neutral on the Cree's, but when you nip the corners, it is? So all of the middle part carries no current or voltage? So if for instance you used one on a heatsink sold on this board for a mag mod, as long as you nip the corners off, it doesn't have to be annodized??

Re: Huh, my led fell off, now what?

I think the middle carries no current. The sides carry current through four little wires(?) within the board(2 on each size). They are the the corners so snipping off the corners removes the connection and makes the entire bottom of the emitter neutral.

Re: Huh, my led fell off, now what?

Sounds like the perfect opportunity to swap the star out for a Q5 star.

Re: Huh, my led fell off, now what?

Marduke said:

Sounds like the perfect opportunity to swap the star out for a Q5 star.

Click to expand...

+1


And you dont need to do any prepping....!

Way to go....

Re: Huh, my led fell off, now what?

VegasF6 said:

*Edit* One more question. The slug isn't considered electricaly neutral on the Cree's, but when you nip the corners, it is? So all of the middle part carries no current or voltage? So if for instance you used one on a heatsink sold on this board for a mag mod, as long as you nip the corners off, it doesn't have to be annodized??

Click to expand...

The Cree slug is neutral. It never carries any current. The contact pads on either side of that aren't neutral until you destroy the traces in each corner. The base can be directly attached to conductive surfaces once those traces are removed.

Re: Huh, my led fell off, now what?

So, to swap in a Q5 would you remove the "star (ok, round)" and put in a new one, or attempt to put a bare Q5 on this star? If so, back to step one, how to attach it? AA?

Re: Huh, my led fell off, now what?

Remove the round board, it would be easier to solder to.

Huh, well that was somewhat satisfying, thanks.
I have to say, that particular RC-G2 was a real lemon, once I got done putting the Q5 in there, the silly old head and reflector wouldn't screw on, so I had to steal one off another RC-G2. And the old one wouldn't screw on the new one either, threads are fubared. Also, couldn't manage to pry off the led base from the front, started to damage the threads on the aluminum pill. So, I had to remove the driver circuit and punch through the back to get the base off.

Other than that, everything went pretty smooth. Output is better for sure, took about an hour. Only been done for about 10 minutes, haven't put a meter to it yet.

Thanks!

Kicksass........!!???




:devil:

Pretty good anyhow. Although, for the money you may be better off just buying from shining beam. But, I had the parts laying around.

Before taking the meter to it, I was going to say that while having the driver out I should have replaced it with something like DX sku 7882, or the universal 19 mode driver, but that requires modding the pill and putting the driver under it, or so I have read.

But, after looking at the current draw from the battery, I guess the onboard driver is up to the task just fine.

RC-G2 Q5

Energizer L91 (well used) voltage 1.44
Current@tailcap - 1.61 1.30 after about 30 seconds (probably not much left of this battery)
Led V - 3.24 dropping to 3.21

Eneloop AA voltage - 1.29
Current@tailcap - 1.60 1.45 after about 30 seconds
Led V - 3.24 to 3.22 pretty steady

RC-G2 P2

Energizer L91 (well used) voltage 1.44
Current@tailcap - 1.67 1.38 after about 30 seconds (probably not much left of this battery)
Led V - 3.13 steady
Eneloop AA voltage - 1.29
Current@tailcap - 1.82 1.50 after about 30 seconds
Led V - 3.16 to 3.14 pretty steady

Considering the lower VF of the P2 I can't explain the higher current draw vs the Q5. I would have thought it would be the other way around, but maybe I have my logic twisted around. :laughing:

Even though you aren't supposed to hook up a boost circuit with no load (usually at least) I did do it briefly with this circuit and I got about 3.7 - 3.8 volts from it so I am going to figure this is a constant current circuit and the voltages at my led are my actual VF's, but even though it is current regulated, it is somewhat dependant on either voltage in, or possibly my batteries just couldn't deliver more of a load.

Next time maybe I will put in a board for a 14500 if I can find something. Or maybe not, I have plenty of other lights to move onto.

Visually, I would guess a 25% output. The one thing I might still do is take apart the tailcap and treat everything with deoxit.