Swap out Emitter on PD-35?

LetThereBeLight!

Enlightened
Joined
Feb 26, 2014
Messages
635
Ok, two Christmases ago I persuaded my friend to get her scientist husband a Fenix PD-35, which he loved (of course, after having seen and played with mine, haha).

Well he used it in his work at his Fusion Lab continuously without it stepping down at all because of the type of battery he insisted on putting in it which he had ordered off of Amazon. I guess it was unprotected because it would not step down ever off of Turbo.

Back then I patiently explained to him how we could not trust any battery that ended in 'fire' but he would not hear of it because its brightest lumens were continuously needed about 2-hours a day for this one daily experiment.

Well, tonight I learned "the bulb died and how do I replace it" which I decoded as the emitter got fried after continuous heavy use! (Trust me when I tell you I have little to none technical/mechanical intelligence, LOL!)

So I have no clue how to swap out an emitter or where to get one. But trust me when I tell you that he can fix/repair anything but he does not know how to open the head of the light (nor do I).

Could it be something other than the emitter?

Does anybody do repairs on something like this?

Is my friend better off just buying a new PD-35?

Thanks in advance for your replies!

-LetThereBeLight!
 

Sledgestone

Newly Enlightened
Joined
Feb 28, 2015
Messages
101
Honestly, you're better off asking this question over at BLF. There are many knowledgeable members there that I'm sure can help you with your modding.
 

FRITZHID

Flashlight Enthusiast
Joined
Jun 20, 2011
Messages
2,500
Location
Icelandic wastelands of Monico, WI
As far as failures go, could be the emitter OR the driver, possibly but unlikely the switch.
Emitter replacements are usually fairly simple and there are plenty of "how to" vids on YouTube.
All that being said, perhaps a light with no "turbo" option would be better for your friend?
 

hiuintahs

Flashlight Enthusiast
Joined
Sep 12, 2006
Messages
1,840
Location
Utah
Like Fritzhid says, it could be either the electronic driver or the LED. With the head apart and the LED exposed, a simple test with a digital voltmeter in the "diode" mode will indicated if the LED is still good. But you have to get the head apart :D and that is the difficult part because it has some Loctite on the threads.

I have two Craftsman rubber strap wrenches that I use. Years ago I got a set of them, one larger (wider) than the other. I put the tail end of the larger strap wrench around one half of the head and then put that in a vice. In other words, I don't even use that strap wrench like it was intended to be used, but just use it to keep the head from being marred in a vice. I then use the smaller one like its suppose to be used in an attempt to unscrew the head. If the head slips in the vice (protected by the rubber of the other strap wrench), then I tighten the vice a little. I incrementally tighten the vice with this method as needed while trying to loosen the head with the other strap wrench. That way I'm only clamping the head in the vice to the point that its held without slipping but also without crushing it.

The 2nd challenge, if you need to swap out the LED, is to know how to reflow an LED onto the MCPCB board that its currently on. You can't just solder them on in the traditional sense as they are surface mounted with no solderable copper exposed. I use a heat gun with a pair of "helping hands vice" to hold the MCPCB about one inch from the tip of the heat gun. Heat gun needs to get hot (no hair dryer). Mine is 1200 watts. Takes about 15 seconds or thereabouts. I place a little bit of rosin flux on the MCPCB with the LED orientated proper (not backwards). As the heat gun warms up, I look for the flux to sizzle and sometimes can see a little solder ooze out. Due to the viscosity of the molten solder under the LED, you can see the LED wiggle and center itself. At that point your done and cut cut the power to the heat gun. You don't want to over heat beyond what is necessary to reflow the LED. I then test with the digital voltmeter to make sure the connections took. One problem you can have is if the center heat sink pad of the LED has too much solder and elevates the LED such that you don't get a connection on one of the terminals to the LED. Then you have to repeat. It takes a couple of practices to get the right amount of solder.

This whole process of changing out an LED is not for the faint of heart :). It also takes equipment that one may not have laying around.
 
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