Help with M6

[jamesmtl514]

Hi all.
Here is a pic with my M4 with Nailbender High CRI LED dropin running off 4x SF123, M6 MN21 with 6 fresh SF cells and my C2 with 3x 16340 with MN60.
Why is the output so much less out of the M6?

C2 with MN60 on LEFT M6 with MN21 on right.

[angelofwar]

Maybe a bad circuit in the MB20? Do a voltage check on the MB20 with the batteries loaded. That's my best guess...hope this helps James!

[jamesmtl514]

Thanks for the suggestion.
The MB20 reads 9.0v. I popped in true fresh cells and they read 9.7v Same output.
I pulled my C2 out of it's pelican case, and it slipped out of my fingers and landed on a tritium sphere making it go

and the C2 was still significantly brighter.

[ampdude]

Are you sure it's not an MN20? Maybe a bad bulb though. An MN21 should smoke both of those setups by a wide margin.

[jamesmtl514]

Yup, for sure it's the MN21. Triple checked. Bulb looks (to my eyes) to be fine.

[angelofwar]

Hmmm...check the resistance (ohms). Do you have another MN21 to compare it to (resistance wise). I'll check mine real quick if you don't, so you can compare it. Also, is it a new or older MN21? Or is there a way to check the amps it's drawing?

[HotWire]

my My M21s (I tested 2) measured 0.5 ohms on my Fluke. I swapped them out real quick and they both have about the same brightness: very bright. You could have a slightly dirty connection somewhere or you might have a substandard bulb. Try another M21.

Edit: If you use alligator clips on your VOM it will help settle the range of resistance to one number. With just probes readout moved around like yours did.

If you know someone else with an M6 could swap the MB20 and see if that is the problem. Then swap the M21s. I don't think your batteries should sag to 4.4v. I'm not an expert, but you either have bad batteries or some extra resistance in the M6.

[jamesmtl514]

I tested the resistance. It jumped around a lot, but finally settled at .3 It stayed there for about 3 seconds then bounced around between .3 and .6 for a bit.
Unfortunately, I don't have another MN21 to test. Checked with my Ideal model# 61-732


Here are some non scientific tests.

at about 2 inches from the wall, examining the hotspots.

The M6 is just slightly brighter than my M91W.
The C2 with MN60 3xIMR16340 is SIGNIFICANTLY brighter than the M6. It hurt to look at the hotspot.

[fivemega]

Do a voltage check on the MB20 with the batteries loaded.

Voltage reading might be good to test batteries (if any) but meaningless for mentioned situation.

I popped in true fresh cells and they read 9.7v Same output..

You may try reading voltage (as close to bulb) and UNDER LOAD or read tail current.

The C2 with MN60 3xIMR16340 is SIGNIFICANTLY brighter than the M6.

This means, you definitely have some problem in your M6.

[jamesmtl514]

Thanks for the input, how would I go about testing under load/ tail current?

[angelofwar]

You would have to run the light while "disected"...if you have some alligator clip and wire you can do it...this will allow you too measure AMPS, etc. You can do it piece at a time. Run a "lead" from the tip of the MB20 to the MN21 while installed in the turbo-head, and use a multi-meter to measure the amps being "consumed"/drawn by the MN20. And do the same for the tail-cap, if you suspect it. The amps should be about the same...if you're getting significantly less from either, that's where the problem is...

Do you have any other Turbo-head lamps? If so, you could use one of those to determine if the lamp is the problem, or if it's in the M6 itself. An N1, N2, or MN15 would work.

[oldways]

Remove tailcap and clean the shoulder at the end of the body threads. Pop out the disc in the tailcap and clean.

[jamesmtl514]

I don't think my multimeter has an amp option. I dissected and connected, made it light up. all i got a reading from was the volts. It was at 4.4v when lit, 8.9v when just the MB20.

I cleaned the threads and removed that disc, cleaned there too. The cloth was removing a little black residue, which just seems like the usual surefire lube (based on the smell and me having owned 30 SFs) This flashlight is in pristine condition. Not even the slightest hint of a blemish.

MN60 is still much brighter.

I have N1, MN60 lamps on hand, What do you suggest I do with those?

[ebow86]

Hello James, sorry to state the obvious but are you sure their isn't a issue with the batteries your using? I know we can eliminate the bulb being the problem, as these bulbs either work properly or they don't, and this one obviously works.

To be honest I am a little perplexed and confused, as you say the "M6 is just slightly brighter than my M91W". That would indicate to me that the M6 is functioning correctly, as the M91W is conservatively rated at 450 OTF lumens and your saying the M6, with it's 500 lumen rating, is slightly brighter, which is exactly what the results should be when comparing them.

But at the same time your saying the M6 is dimmer than your C2 with MN60, but then you go on to say that the M6 is still brighter than the M91W?. The M6 is dimmer than the C2/MN60 but still brighter than the M91W? I don't understand how the M6 can be brighter than the 450 lumen M91w but at the same time be dimmer than the C2/MN60? That seems contradictory to me. Ok, now I'm getting confused, just trying to understand the comparesons you've made here.

Sometimes comparing the output of different lights can be confusing, as the beams and color temperature can vary greatly, and that can make it difficult. Also the first photo you posted looks very much like weak cells to me, the yellowing is typical of what happens when the cells are weak. That MN21 really sucks the life out of the cells, and runtime is painfully short.

[jamesmtl514]

I know... I'm confused too.
The cells that I used for the above pictures had about 2 minutes runtime on them. I even replaced them with cells that I individually tested to be fresh, and I got the same output.

As you see in this picture.

The MN60 is white and really bright. The MN21 looks very weak.
Last night Before going to bed I shined both of them into the night sky and the MN60 produced a very smooth, bright beam. The MN21, not so much.

I'm in talks with someone in the MP, trying to get my hands on other MN21 bulbs to see if that helps.

[angelofwar]

James,

Do a search on running an N1 bulb in the M6...I did a thread up a few years years ago. If the N1 isn't as bright as a P60 (approx.), then we know it's not your bulb, but something with the light or the battery holder. I'll try to find the thread and will post it if I do.

[angelofwar]

Bumped it to the top of the incan thread, but here's the link JIC:

http://www.candlepowerforums.com/vb/...79-N1-in-an-M6

[ebow86]

FWIW I have run the MN60 on 4 primaries and done several comparisons with the M6+MN21 on primaries and there is no comparison, the M6 easily was significantly brighter and whiter every time. I have seen both lights in person and I would completely agree with the assessment that "The M6 is just slightly brighter than the M91W. See this post here http://www.candlepowerforums.com/vb/...=1#post3739731 You can clearly see where I mention the M6's output is brighter and whiter than the M4's.

That still doesn't explain to me why the M6 is supposedly brighter than the M91W, which sounds perfectly normal, yet it is not as bright as the C2/MN60? Again that doesn't seem to make sense to me, as your M91W should easily output more light than your MN60. Any chance of a beamshot of your M91W vs M6? The M91W should appear to be dimmer or slightly less bright than your M6, correct? That would be hard to beleive judging by the beamshots you provided, yet you have already confirmed that the two are similar in brightness with the M6 being slightly brighter. So with that said, we can determine that your MN60, rated by surefire at 225 lumens, is brighter than your M91W rated at 450 lumens, correct? Wow, very confusing.


Lamp Assembly's either work or they don't. I've never seen it when a "defective" lamp assembly was significantly dimmer than a normal one, it's always either they work or they don't. There are rare occasions when the gas can escape from the globe and cause the output to be extremely dim and yellow, and then the bulb proceeds to burn out fast and die, but that's obviously not the case here. Lamps darken with age and the output can be reduced, but typically it isn't very severe.

[ebow86]

James,

Do a search on running an N1 bulb in the M6...I did a thread up a few years years ago. If the N1 isn't as bright as a P60 (approx.), then we know it's not your bulb, but something with the light or the battery holder. I'll try to find the thread and will post it if I do.

AOW, isn't the N1 a 6 volt LA for the KT1? Won't it burn out or explode in the 9 volts the M6 is going to give it?

[angelofwar]

Yes, but when I decided to run it in my M6, I used two CR123's and a spacer. If you do a continuity check between the connections on the MB20, you can arrange them right, and get 6 volts out of it. I explain it in my M6/N1 thread...the best I could explain it, anyways.

[ebow86]

Yes, but when I decided to run it in my M6, I used two CR123's and a spacer. If you do a continuity check between the connections on the MB20, you can arrange them right, and get 6 volts out of it. I explain it in my M6/N1 thread...the best I could explain it, anyways.

Gotcha, sound's like an awesome setup, those N series LA produce such beautiful round hotspots.

[jamesmtl514]

Just got in, here are some photos for your consideration.
M91W with 2x 18490 vs. M6 with MN21
M91W is about an inch from the white molding. The MN21 is about 3 inches away. you can see the tip of it at the bottom of the photo.


C2 with extender and KT 3x 16340 with MN60 in vs. M6 with MN21. M91W with 2x 18490 on the floor.
Both incas are about 4 feet from the wall.


Reversed this time.
MN21 on left, MN60 on right. Pointed at the ceiling. about 8 ft away.(~9 ft ceiling, 12" light)

[DM51]

james, the MN21 pulls about 5.0 amps out of 3s2p CR123A primaries. It works them about as hard as they can take, so it is essential to use top-quality cells.

The voltage under that load drops to around 7.0-7.5V, so I'm a bit puzzled by your reference in post #13 above, where you measured 4.4V. How did you measure that?

[jamesmtl514]

I have only used Surefire batteries.
I achieved the 4.4v by running wires from the MB20 to the MN21 forgoing the M6 body.
I placed my multimeter leads on the outer and inner springs while the light was lit. It gave me 4.4.

**************************

If anyone here can post beamshots of their MN60 and MN21 side by side like I have that would be greatly appreciated.

[DM51]

At 4.4V the MN21 will definitely under-perform, with the result you've seen. Either the cells are old or used, or the MB20 has a bad connection that bypasses one of the cells.

[jamesmtl514]

I tried 2 sets of new cells. I'm leaning towards a bad MB20 at this point. How would I go about testing it?
(I will attempt AOW's N1 vs P60 method when I get my multimeter later on this evening)

[angelofwar]

I'm with DM51 on this one...Bad MB20...I'm Sure SF will swap it out for ya.

At 8' the MN21 should appear a little brighter than the MN60...and "white" for that matter.

Here's a quick diagram I did up showing how your MB20 should be wired to make up the two parallel 9V stacks.

[DM51]

I'm not sure exactly how the MB20 is wired up. Just looking at it would suggest it is 2s3p, but it's 3s2p. What order the wiring goes inside, I'm not sure.

I may be wrong, but I think someone has taken one apart before - probably LuxLuthor. I think I recall seeing something about it a long while ago.

Try various combinations of just 3 cells to get a reading of 9V at the +ve and -ve terminals of the MB20, then take those out and put 3 cells in the other 3 spaces. If there is a faulty connection, a reading of 0.0V will reveal it.

[DM51]

BTW in post #28, take those readings open circuit, without a bulb connected...

[angelofwar]

Ha-Ha! just did that diagram up while you were typing yours, DM!

Try various combinations of just 3 cells to get a reading of 9V at the +ve and -ve terminals of the MB20, then take those out and put 3 cells in the other 3 spaces. If there is a faulty connection, a reading of 0.0V will reveal it.

If you do this, just make sure you do it in a timely fashion. There's a "loop" in the circuitry...if you just put 3 in, or 4, etc., and they're not right (say you put batteries in A1, A2, and B2), and you accidentally leave them in there, they can get extremley hot (and probably go poof on ya)...it's either 3 in the right spot (A1, A2, A3), all, or none.