re: ARC LS First Run-- emitter swap possible?

re: ARC LS First Run-- emitter swap possible?

just picked up a First Run and want to put in one of the beauteous Q3Js floating around (thanks to Cuong) ...

tried to unscrew the bezel by hand and then with a rubber-padded slip joint pliers and it seems pretty firm ..

anything I need to know, like whether it's even possible?--I assumed from the grey kit that this does unscrew and give me access to the circuit board ... false assumption?

/ubbthreads/images/graemlins/help.gif

thanks in advance

hideo

Hello hideo,

Some of the first run has pee green led, swap an emitter and you will have a beautiful light which can run on a 1AA battery. However, you will need some patient and time to do it.

A quick run down, you need to heat up the light so the epoxy will soften, then using strap wrenches to unscrew the bezel. Scour around the forum, there have been discussions about disassembling the first run. It's a pain to do it, but it's really worth it.

Vince.

thanks Vince!

I'll start with the hairdryer before i fire up the propane torch ... /ubbthreads/images/graemlins/wink.gif

hideo

The first runs suffered from what's called "flex failure". Just be aware that when you disassemble the head, you might run into this. If you do, post back here or PM me. I can possibly help with a workaround. The newer heads don't suffer from this.

CM

GAH!-- I hate too see the "f" word in a "how to" post ...

is that a failure of the circuit board or ...?

thanks

hideo


PS Klaus and CM--thanks for all the tips ...

Typically I wouldn´t interfere with CM but on this he´s not 150% correct IMO - the flex failure was with the hybrids only AFAIR - the rev1 housings using the rev2 circuit boards. As it sounds we´re talking about a full rev1 LS which didn´t never had the flex failure due to other design of the circuit board.

I did a Q3HD2first run transplant myself and I want to add some comments - to open the bezel heat and strap wrenches are the way to go as was said already. Further complicating the issue is the black epoxy Peter was putting on the circuit board and emitter in those days. You have to cut this away from the emitter to swap it. McGizmo and others commented on this in old threads - heating the epoxy slightly helps quite a bit. Look up old pics of the rev1 circuit boards like on the Ebay auction sale from ARC on pics for this black thinggie.

Also take care to use the lowest Vf LS you have on hand as the old circuit is voltage driven and not current regulated - the lower Vf you use the brighter it will be.

I fully agree that this is one mod well worth the trouble

Klaus

Does that mean I'm only 100% correct? Gotcha Klaus /ubbthreads/images/graemlins/grin.gif , hehe. Anyway, I always thought flex failure was a problem with all the LS's until they went to the new one-piece housing. They incorporated a beryllium ring to take up any slack produced when the battery pressed up against the circuit board. Before the implementation of this, the pressure of the battery on the board was enough that on some lights, the board would lose the (-) connection causing the light to flicker or even go out. I could be wrong, my FIFO memory isn't very deep these days and useful info sometimes get thrown into the bit bucket /ubbthreads/images/graemlins/grin.gif

I´m not 100% sure on it but my fading memory remembers this way - as the design of the old circuit board is similar in regards to the minus connection to the body it might well be - this is why I mentioned those 150% /ubbthreads/images/graemlins/blush.gif

Klaus

I am not sure what sort of flex failure you guys mention.

However, my first run has a bezel that can't be screwed in entirely, there is a 0.6mm gap. I guess the circuit board is too thick, compressed tightly on to the body when tighten, therefore no flex problem? I can unscrew the bezel anytime, I leave the head free.

Vince.

Here's one discussion of the problem

Arc LS Flex Failure

for those of you that have swapped emitters in these do they have good enough heat sinking and what current/voltage do they run at ?
Thanks Chris