Petzl XP Upgraded

Here is the insides of the headlamp. I'm not sure what the purpose of the shield is. It's not thick enough for a heat shield. I think the small component sunk in the thermal paste is the thermal shutoff sensor.


There was a blob of paste on top of the star that connected to the shield.
Note the star is a TV1J. Nice flux, crappy tint and a good vf.


Here is the pulled out board next to the lens holder. The lens just drops out.

The following picture is the XP lens on the left next to a Freon and a NX05.
It is a much lower profile and about 2mm larger diameter than the other lens.


As the LUX-III appears to be easy to change, I'll be putting in a TWOJ. I lost the Luxeon lottery on the present LED in the XP as the tint is a lousy sickly yellow with a strong hint of green.

More information. As I'm changing the LUX, I did some current measurements.
Low=50ma
Medium=175ma
High=335ma
Boost=600+ma (my meters limit)

All in all, the unit apprears to be way underdriven, except for boost mode that most likely drives it at spec.

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sunspot said:
I'm not sure what the purpose of the shield is. It's not thick enough for a heat shield. I think the small component sunk in the thermal paste is the thermal shutoff sensor.


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See if the heat sensor actually shuts off the boost mode. If you could do a better job of heatsinking the LED and get boost mode to last for several minutes, I'll bet the Myo XP would be a much better headlamp.

But if it the boost shut off uses a timer, there won't be much to gain from adding extra heatsinking.

Also, to take the headlamp apart did you have to cut plastic, or were there screws holding it together?

Thanks for the write up. The photos are very well done.

Is there room for full blown regulation in there?

thanks

Curtis

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cue003 said:Is there room for full blown regulation in there?

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If you want to have regulation, it would be wise to change to less or more cells.
For example using 4AA cells and a step down converter.

Wouldn't using lithium AAs against the 335ma draw on high provide very flat, and very long continuous runtime? Medium would be double that runtime, etc.

cue003 beat me to it. Since you've gutted it, why not super-tweak it? /ubbthreads/images/graemlins/crazy.gif

I wonder if that optic is custom made?

Thank you for the responces. /ubbthreads/images/graemlins/smile.gif Sorry for the slow posting. I've been a bit under the weather. /ubbthreads/images/graemlins/sick2.gif

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mrme said:
See if the heat sensor actually shuts off the boost mode. If you could do a better job of heatsinking the LED and get boost mode to last for several minutes, I'll bet the Myo XP would be a much better headlamp.

But if it the boost shut off uses a timer, there won't be much to gain from adding extra heatsinking.

Also, to take the headlamp apart did you have to cut plastic, or were there screws holding it together?


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I'm only guessing about the component in the paste being a thermal sensor. I do believe that a slug could be added on the star for additional heat sinking.

This could be a great headlamp if the current was higher to the LED.

The takedown was very easy. Four small Allen screws hold the backplate on.

[ QUOTE ]
cue003 said:
Is there room for full blown regulation in there?

thanks

Curtis

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I don't know. I never made one. It would be nice to have. /ubbthreads/images/graemlins/blush.gif
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greenLED said:
cue003 beat me to it. Since you've gutted it, why not super-tweak it?

I wonder if that optic is custom made?



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The takedown I did was not difficult. I did not remove the yellow plastic that is on the other side of the board because that cover holds the switches and power indicator. I may not have been able to reassemble it.
I don't have the skills to tweak it. /ubbthreads/images/graemlins/icon23.gif It would be nice if the current levels could be upped.
I do think the optics are custom. I've never have seen the likes before. It has a very low profile and is very concave on the top. So much so, that there is hardly any room between the LED and the top of the optics.

<sheer speculation mode> Might the metal shielding be intended to reduce RF interference with radios, avalanche detectors and the like? </sheer speculation mode>

--Rick

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Skeeterbytes said:
<sheer speculation mode> Might the metal shielding be intended to reduce RF interference with radios, avalanche detectors and the like? </sheer speculation mode>

--Rick

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The Myo XP is not regulated, so I doubt there would be an interference like you can get from pulse width modulating regulators.

If the star is mounted to it and a component is stuck to it with thermal grease, I am pretty sure it is a weak excuse for a heatsink.

If I ever get around to buying one, I will definitely do some modding of the heatsink. Possibly even getting the aluminum inot ambient air.

Heck, I would probably scrap all the circuitry and put in a respectable regulator. Imagine how cool it would be running on Li-Ion AA's and a Uflex regulator. Oh, if I only had the cash!

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mrme said:The Myo XP is not regulated, so I doubt there would be an interference like you can get from pulse width modulating regulators.

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The Myo's different levels are made via PWM.

They definitely have a green glow but I find the greenish white to have a weird increase detail when using it, more so with diffused and not as hard on the night vision . Seems to return quicker after the lights is off. I always found that the bluish white to cause everything to have a hazes around it and harder on the night vision.

Now when you put new batteries in then they look even better for the first couple off minute . with a new set of batteries the pack measures 4.8 v as it sits and 4.5 v under load . after 5 min it drops to 4.3 v and 3.9 under load .It look like there is no fancy level setting just some simple voltage dividers there for if you up the voltage you will up the current.now you cant go to far because you are upping the over all power and it not the lamp I would worry about but the other components in the circuit.
/ubbthreads/images/graemlins/wink2.gif /ubbthreads/images/graemlins/wink2.gif so where can I find a regulator set in the 4.8 to 4.5v range designed for 3 AAA as a source for a 3w lux. It doesn't need to fit in side ,just need to cut it in to the cable. Can some one point me in the right direction /ubbthreads/images/graemlins/wink2.gif /ubbthreads/images/graemlins/wink2.gif

I figure that would be the easier then playing with the levels

Over all I like the xp can't wait for the 5 w version with regulation

Don

Has anybody got both the myo xp and the tikka xp? I really like the concept of these lights, but I'm a bit concerned about a couple of things.

1. The myo has a separate batttery pack. I don't like that much.

2. The tikka only seems to have a 1W lux. What gives?

Any opinions? Or has anybody taken the tikka xp apart?