Replacing the emitter on a MM; few quick questions

[StoneDog]

Hi, I'm attempting to replace the emitter on a MM sandwich with a Q3 HD. This is a huge project for me because I have basically no soldering skills whatsoever. /ubbthreads/images/graemlins/crazy.gif

My first attempt failed miserably, I trimmed the emitter's leads too short and managed to bridge the positive lead to the rest of the sandwich's top board. /ubbthreads/images/graemlins/frown.gif Now I've got solder all of the place and need to clean up the sandwich before I try again.

My questions are pretty simple though, how much heat can the emitter and/or sandwich take before I fry one of them? I've got a temp. controlled iron if that helps... And, I fired it up twice to see if I was successful - any chance I fried one of the components in the MM with the short?

This is a very humbling experience, thanks for any help or advice.

Jon

 

[dat2zip]

Re: Replacing the emitter on a MM; few quick quest

The converter board components can take the full heat of the soldering iron with no problems. Not sure about the epoxy. Depending on the epoxy used, it can get soft as low as 120F.

The LED can be damaged by too much heat. Not sure you have fried one yet.

Hope this helps. Sorry to hear about your sandwich.

Wayne

 

[StoneDog]

Re: Replacing the emitter on a MM; few quick quest

Thanks Wayne, it does help. I care less about the Q3 than I do the sandwich itself.

If I can ask a follow-up question, how will heat affect the emitter? Will it cause it to have diminished output, or just plain break it?

I ask because after I desoldered the Q3 from the sandwich I tested it with two fresh 2 AA alkalines. It was noticeably dimmer than the Q2 batwing (3v DD from two alkalines also) that was originally on the sandwich.

Jon

 

[dat2zip]

Re: Replacing the emitter on a MM; few quick quest

Jon,

DD will vary the light output dramatically since the Vf between LEDs are can be quite different.

On a 2AA setup a low Vf can skorch your fingers in no time and a high Vf will barely light up.

It's probable you have not damaged the Luxeons at all.

Heat will degrade almost any LED. But, a 1W or 3W degraded even severely still would have many thousands of usefull hours and this translates to many years for a flashlight use.

For fixed lighting where the light could be on 24 hours a days might warrant staying within the Luxeon specifications.

Wayne

 

[StoneDog]

Re: Replacing the emitter on a MM; few quick quest

I wonder of the Q2 that came with my MM Wide Open was an "H" or "J" (based on it's output at 3v)?

Either way, thanks for taking the time to respond. I'm off to practice soldering...

Jon

 

[StoneDog]

Re: Replacing the emitter on a MM; few quick quest

Wayne (or anyone?), one more quick question if I can...

Do both the positive and negative leads on the emitter need to be isolated from the top of the sandwich?

Jon

 

[dat2zip]

Re: Replacing the emitter on a MM; few quick quest

Jon,

The negative is commom with the GND or the top of the emitter board.

 

[StoneDog]

Re: Replacing the emitter on a MM; few quick quest

Ok, so I guess I only need to clean up the side of the sandwich that has the positive connection. /ubbthreads/images/graemlins/smile.gif

Thanks again for your help Wayne.

Jon

 

[StoneDog]

Re: Replacing the emitter on a MM; few quick quest

OK, I was able to clean up the extra solder and put a nice Q3K HD on my sandwich. It was a learning experience, but I know just enough to be dangerous now!

With this first project under my belt (as they say), I then built a Black McLux PR head with a DB700 and TX1K. It came out perfectly and looks great on a Scorpion body. /ubbthreads/images/graemlins/grin.gif

Thanks again for your help Wayne, without you and this forum I wouldn't have gained the parts or knowledge to make this possible. /ubbthreads/images/graemlins/smile.gif

Jon

 

[StoneDog]

Re: Replacing the emitter on a MM; few quick quest

OK, I guess I didnt' do something right... The Q3K on the MM gave a purplish beam that was not significantly brighter than when I tested the emitter DD w/ 2 alkaline AA's. (The beam was also pure white when I tested w/ 2AA's). Additionally, the Q3K/MM combo grew dimmer over the course of 4 or 5 minutes.

After I noticed it had dimmed I immediately pulled the module out of the mini-mag and the anode contact was almost too hot to touch. The top of the board was not warm, neither was the emitter.

I'm kind of bummed and would like to know what went wrong so I don't do the same thing again.

Possible problem points:

- I am using JB Weld as the adhesive so there's a chance it was somewhat conductive.
- The solder connections to the emitter were pretty bad and might have added to the overall resistance of the emitter (if that is even possible?).
- The top of the sandwich has been chewed up pretty bad as I attempted to clean up excess solder with and exacto knife. /ubbthreads/images/graemlins/icon15.gif
- Too much heat may have been applied to the emitter through the leads and/or to the MM board throught he connectors.

Any thoughts on why I get a dim purplish beam that grows weaker over the course of a few minutes?

Jon

 

[Slick]

Re: Replacing the emitter on a MM; few quick quest

[ QUOTE ]
StoneDog said:
Any thoughts on why I get a dim purplish beam that grows weaker over the course of a few minutes?

Jon

[/ QUOTE ]

Are the batteries good for sure? The "drop-off" sounds like weak batteries maybe.

I need to replace the emitter on my Q2 Madmax as it is "rotten dog-urine green".

When your removed the emitter from yours, was there any glue holding it on? -thanks..

 

[red_robby]

Re: Replacing the emitter on a MM; few quick quest

[ QUOTE ]

Any thoughts on why I get a dim purplish beam that grows weaker over the course of a few minutes?

Jon

[/ QUOTE ]
sounds like there is an intermittent short to me.

 

[StoneDog]

Re: Replacing the emitter on a MM; few quick quest

[ QUOTE ]
Slick said:
When your removed the emitter from yours, was there any glue holding it on? -thanks..

[/ QUOTE ]

Not much, if any. I think it may have just been AA grease, or maybe a small amount of AA Adhesive?

[ QUOTE ]
Slick said:
sounds like there is an intermittent short to me.


[/ QUOTE ]

May be. I removed the emitter and and scraped away the JB Weld. The top of the sandwich is pretty much trashed now so I went ahead and scraped away all the copper near the positive lead just to be safe. I then AA Epoxied the emitter back in place and re-soldered the connections. The light isn't really the "angry purple" anymore more and hasn't dimmed noticeably in 5 minutes, but it is also much, much dimmer on the same 123 than an R2H/MicroPuck combo. I think a combination of higher Vf, lower flux and perhaps higher resistance from crappy solder may be the culprit.

I've pretty much ruined this sandwich - it is pretty much toast IMHO - so I'll leave it as a tool box light in a mini-mag or something. /ubbthreads/images/graemlins/icon15.gif I guess I just need to order some new ones from the Shoppe! /ubbthreads/images/graemlins/grin.gif

Jon