Learn From Mistakes That Can Happen To Anybody...

[styropyro]

Recently I was building a PHR-803T module with a LM317. I thought that the heatsink was the V-in pin, not the Adj pin. So I hit the poor diode with several amps from a computer power supply. Now it is a zombie diode that sill lases, it just is weaker.

Also as I've said many times, I blew one of the new 445nm diodes by using an Aixiz acrylic lens. The lens melted on me and fried the diode.

 

[Burnsy]

I have a pocket chrome mini 12x (signature) that it's dead now and on the way to repair
This is how I done it:

The lens in the Aixiz module was wobbling and I didn't like the idea of using teflon tape to wrap around.
I put a o-ring at the end of the thread from the lens so when screwing it in and getting to the focalpoint it's putting pressure on the o-ring and it doesn't wobble anymore. But it does another thing... when focusing from close to far distances it looses the pill and the heatsink and because they were only glued together for putting in, the two parts turned independently and caused a short

So now it's either the diode, the driver or both dead

 

[jayrob]

I have a pocket chrome mini 12x (signature) that it's dead now and on the way to repair
This is how I done it:

The lens in the Aixiz module was wobbling and I didn't like the idea of using teflon tape to wrap around.
I put a o-ring at the end of the thread from the lens so when screwing it in and getting to the focalpoint it's putting pressure on the o-ring and it doesn't wobble anymore. But it does another thing... when focusing from close to far distances it looses the pill and the heatsink and because they were only glued together for putting in, the two parts turned independently and caused a short

So now it's either the diode, the driver or both dead

Oh man... hope it's not the diode...

It's a good practice to give a good final tightening of the pill up against the heatsink after the assembly is threaded all the way in...

You can use the tips of some needle nosed pliers to catch the two notches in the pill, or even catch on the solder blobs.

This is not only necessary to keep the heatsink from being able to turn, but also gives better heatsinking. Turning the entire host into the heatsink...

 

[WRM]

I am used to putting a laser without aperture cap into a ziplock baggie to keep dust off of the lens. This incident was with an LED shoppe 532nm 50mW with the push button switch that must be depressed constantly. I reached into my pocket and unaware that the laser was actually pointing up, I grabbed it by the button and the beam shot up right past my eye. I did not sustain damage as I received an extensive eye exam for another reason, so I was very lucky. A hit that close with unfiltered 50mW would be bad. Watch those instant press buttons. You never know when you will accidentally grab the laser and inadvertently press the button. Bill

 

[pokerface3699]

Re: Mistakes That Can Happen To Anybody...

I removed, destroyed, and trashed a perfectly good >$300 diode because I forgot that the flexdrive will "shut off" when the voltage from the battery gets too low.

It was a 6X back in the day when we were still buying >$300 drives to harvest the diodes from. The diode was in a Kryton Smooth with a flexdrive. I was "pushing" the diode so was always anxious when I turned it on the first time that day. Well I turned it on and it was dark.

I cried my tears and changed the diode (destroying it in the process). When I turned on the laser with the new diode, it was still dark. I thought back through what I could have done wrong to blow the new diode when I remembered about the "shut down" threshold of the flexdrive.

I recharged the battery and everything was fine. Only then did I realize that the other diode was fine as well.

Always check the battery first!

Peace,
dave

I had something similar. I thought a good phr was dead because once I turned it on, it grew bright, then dim shortly after. I was very shocked and sad because it was my first laser. I thought it was one of the phr's that were infamously unreliable. So I used a crude method of taking it out of the aixiz housing (it consisted with a ceramic rod and a wrench), destroying the glass and then destroying the laser diode. I then bought an sf aw 6x diode. I used the same battery as the phr and the same thing happened with the 6x, bright, then dim. I became shocked and sad again, but i accepted the fact. Later, after a while (the battery rested) the laser ran smoothly, then after some minutes, same dreaded dimming. I checked the 9v battery and saw 7 volts. I used an ac adapter (8 volts) and it has been working smoothly ever since. The phr mightve been good, but hey, i now have a 6x blu ray diode. Guess i cant complain.

 

[Moptsp]

What about safety mistakes? If so....

Never make a laser beam bounce between two mirrors 7 times without safety glasses on, even if it's 5mw.... Or it might jump directly into your eye on the last bounce....

Did that with my WL 5mw Core. Scared me. Getting a laser in your eye is nothing like looking into a bright light. It's like putting a bright light in your eye. It completely illuminates it and you can't see at all. Thank god it was 5mw, Ill never do mirror bounces without safety glasses to at least SET IT UP no matter the power it has.

 

[jupiter8]

Great thread! I'm learning heaps reading through these. here's my contribution:

Last night, I received an order of LPC-815 diodes from Stonetek. Got it pressed into the module fine, leads soldered on quickly and accurately, tested it - all good. I had it on - o-like driver set to 300mA and was gently winding in the lens to the focal point - the driver was powered through a 9V socket tranformer plugged into a power board - also plugged into the same powerboard, my smoke machine - I hear a "click" as my smoke machine element comes up to temperature and the relay cuts the power and at EXACTLY the same instant, my LPC-815 goes off. Dead... tested... definitely dead. The smoke machine had produced a savage voltage spike which went RIGHT THROUGH my driver and fried the diode in an instant. I hate that sinking feeling you get when a diode dies... lucky these were only 8 or 9 bucks.

 

[NightRunner417]

Today, we gather to give thanks to the Lord our sheppard, for the gift that was our beloved friend, blue laser diode...

Sad but true, I was putting some final touches on the casing and the heat distribution system for my blue 1.25 watt laser build, with the batteries in the damned thing, and I slipped somehow and shorted just the right spot and blew the diode:

WAHHHHHHHHHHHH!!!

I knew I was begging for it but I thought I could slip it together without having to remove the batteries, which fit in the holder really tight, but alas I guess not. For what it's worth in terms of info for the group, this laser diode came into my hands about two months ago, and saw several changes in driver design and output power before this accident killed it. It began life in one of my small plastic cased pocket designs, operating at about 300 milliwatt. From there, I upgraded the driver board a couple of times, and ran the diode at increasingly higher powers. First, I made the 500mw mark, then 600, then 800, then up over a watt. Eventually I came to understand enough about the system to know what was holding it back from running yet higher, and I made the changes happen and ended up with a watt and a quarter, which is where I decided to let it stay. Running such high power quickly caused issues with heat dissipation, so I engineered an aluminum casing for it and gave it a largish heatsink for the diode housing. I ran it again and again at a full 1.25 watt or higher (I don't have an LPM so I am guessing based on the curves we've seen so far, with the input current at about 1.25A), gave it all kinds of burn tests and runtime tests, and was very impressed with it overall. Today, I was working on finishing up some of the details of the casing, and also was completing the heat transfer tab to channel heat from the current regulator to the casing, and I apparently bumped a sensitive spot and made just the right short. The diode emitted a brief and bright blue flash, and no more. I removed the diode, tested the circuit, tested the diode itself, and found that it was completely opened.

I'm already hot on the trail of a new diode, which hopefully won't take long to get here. Till then, I'll be focusing on adding the final touches to the casing and driver circuit (fan cooling, a modulation input jack and a safety killswitch), and then when the diode arrives, it will only take me a few mins to mount it and it'll be all done.

All I can say is next time, NO BATTERIES (when will I ever act like I know how risky this is???) and praise God these things don't cost hundreds each!

I've killed lots of other diodes... I'm practically the laser diode grim reaper. Each and every time, it could be attributed to impatience. For some reason, even when I have lots of time, I am trying (as I have seen others post about too) to cut corners and get things done quickly. Most of the tragic losses have been due to capacitive discharge because the power was hot while the laser diode was out of the circuit. Even when the power is turned back off to put the diode back in, unless there is a bleeder resistor across the cap and you give it time to actually DO something, it will still pop the diode. Depends on the value of the cap and the value of the bleeder, but I tend to use large caps across LDs and high value resistors, so there you go. My first kills were a couple of 5mW and 10mW reds, and then some 200mW reds. The most copious slaughter was when I decided to get into 405nm violets pulled from PHR-803 sleds... talk about a bloodbath. I killed a couple just by that capacitive discharge thing, somehow knocked the window glass down into the can on another (but it still worked for a long time!) crushed another, and killed a couple more apparently by overheating. I've decided that 405's don't like me at all, and frankly although I think the beam and dot are amazing to look at, I really don't like them as a laser in general, especially after all the losses I've taken. This today marks my first blue kill, and hopefully my last.

As for pops in the eye... I've had a few of those too. My first bad one was a hit in the eye from a tweaked leadlight green DPSS, reflected back at me by window glass at close range. DUH! I took the reflection of perhaps 30mw right back into my eye for a split second, and wow talk about bright. Another time, very recently, I caught a somewhat specular reflection from the backside of a loose potentiometer on my desk while testing my latest 200mW red build. That one was pretty shockingly bright, and I may have taken some light damage from it but not sure. Even more recently, and more scary, I took a reflection into my eye by pointing my first blue ~500mw build down into a glass of iced tea to see if it would fluoresce. Wow... BRIGHT! I don't think it did any damage (the beam reflection may have been very distorted from the liquid surface, and reduced as well) , but I won't be doing anything like THAT again. That same blue build has now been improved to produce around 1.25 watt, which is just SUPER scary. You simply can NOT be too careful with lasers of that kind of power output.

I hope never to have anything more to add to this thread. ;-)

 

[benmwv]

Once i inadvertly laid a 150mw o-like green module i was making into a laser to sell to my friend on an unlevel table and it rolled right off, onto the tile floor. Made a loud sound and i knew it was broke. i hooked it to power and saw the red glow, took it apart and sure enough, the epoxy holding the crystals on had fell off and there seemed to be some damage to the diode too.

 

[AUTO XX]

My first 445 build was in a pointer running at about 250mA just to see where the lasing threshold really was.
I was using a DDL driver with 2 10ohm resistors and just playing with the (one turn) pot.
All of a sudden it went super bright then nothing?!?!
A stray piece of wire, cut from the end of a resistor (the 1/2W thin ones) was right underneath where the driver had been sitting.
Innocent looking little bastard cost me a a130 diode!
My girlfriend was drawn to the kitchen by the unique and apparently rather imaginative verbal assault directed at myself, the diode, the driver, the piece of wire, and yes, even the color of the tablecloth.
I guess I had never cursed around her in the 2 years we have been together and she found it amusing.
Funeral services were held for it the following evening.
*Girls just don't understand these things*
Moral of the story: Clean up your table before testing, the diode module wasn't even strapped down. Would have been pretty easy to catch it in the eye scrambling to hit the kill switch

 

[viperx1101]

I thought I would share a problem that I had a month or two ago and just a week ago I finally figured out what happened!!!! Here Goes...

Also, here is a link to the whole story and many members trying to help me out: 8x Bluray problem with pulsing diode

I had just finished my first 8x bluray build using jayrobs C3 Stainless Steel host and microboost driver running at 305mA. I was using a 405-G-1 lens and a 14500 battery that goes with the host. When using my laserbee I, I was finding output in excess of around 580mW, when I should have been getting around 400-450mW output. And it only stayed this way for about 5-15 seconds then the diode started to pulse around 3-4 hertz. I definately knew something was wrong, here is a picture of the results:

After about a month and a half, I finally came to a conclusion on what I was doing wrong. And it definately WAS my fault!!!

Everything was set up how I thought it was supposed to be setup with a Microflex drive (the mistake). The only problem was that I was using a Microboost Driver, and I didn't know that these drivers were wired differently. I had my 8x with driver, batt and host set up like this:

(Also, I know these pictures have text stating it is a CR2 host with 445nm diode, but I also did that 445 build incorrectly with the MicroBoost Drive and that is how I figured out my problem.)

Anyone that is informed about the differences between the MicroFlex Drive and the MicroBoost Drive will imediately see the problem here. I incorrectly soldered the case pin and the negative pit together, and then soldered both of these to the diode negative out on the MicroBoost drive.

I figured out during PMs from Jayrob that I was actually supposed to keep the Case and negative pin on the diode seperate. Then I would solder the negative pin to the Diode negative and the case pin to the Battery negative input. Here is the corrected Picture:

Once I figured this out, I was able to correct the problem, but sadly I already L.E.D.ed my 8x and a 6x diode. I guess that was why I was getting such high readouts from my Laserbee 1, because, IIRC, doing what I did basically bypasses the driver and gives direct current from the Battery to the diode. And that is a lot of current!!!

I also did this same incorrect soldering with a A140 Casio 445nm diode, but luckily those diodes are monsters. And after I corrected the mistake on that build, the diode worked just fine.

This was definately a experience that I will learn from and the knowledge that I gained will no doubt help me out in many of my future builds.

 

[Addonex]

Never pot-mod a laser pointer. I remember when I got my first green pointer when they were still around 70$. An expensive lesson to learn about something I now know is just silly to do

 

[AUTO XX]

Yeah, ^^^^^ don't do pots kiddies! :crackup:

 

[roddenberry]

Laser diodes have these annoyingly tiny tiny little leads that aren't compatible with big clumsy fingers... My first attempts at soldering wires on a diode ended in catastrophic solder blob messes.

One trick I use now to solder wires to a diode is to "pigtail" the wire itself. After pressing the bare diode in an aixiz module end, I take a very fine wire (finer than 22 awg telephone wire, so 26 or 28 awg) and wrap it around the butt end of a steel sewing needle that's about the same gauge as a diode pin.

I then carefully remove the wire off the needle still in a pigtail and slip it on the diode pin, not all the way so that the end of the pigtailed lead doesn't touch the diode case. With a well-cleaned iron, I quickly solder the lead to the pin with my thinest solder and then slip a piece of thin shrink tube. I shrink the tube with a heat gun and voilà!

The resulting joints are very strong and resistant to wire flexing around while inserting the combo driver/module in a host. Here's a little sketch describing the process:

Robert

 

[NightRunner417]

Got a new one to post, courtesy of the repairwork this afternoon on my blue laser.

What happened is, when I went to press the new diode into the head of a common 12mm housing, my drill press based setup slipped somehow and the diode slid to one side in the housing hole instead of going in straight. It wouldn't have been any big deal except I always run a film of heatsink compound around the hole before inserting a diode, and this time I used some leftover Arctic Silver II from some computer work in the past. Wouldn't you know it, some got on the diode window - WHAT A MESS. I had to clean it up CAREFULLY by hand with q-tips and acetone. Despite my best efforts, the out of focus laser dot still has a slightly mottled appearance, meaning there's a bit of a residue there. Everything works and the beam power is fantastic, but I do worry that over time this might shorten the life of the diode. You can't be too careful with these tiny, delicate parts!

BTW Roddenberry, nice trick with the "wire wrapping"!

 

[drummerdimitri]

NEVER clean your high powered 445 laser diodes with a Q-tip and alcohol while the diode is lasing! I thought the extra heat would help with the cleaning process, but instead left a black spot in the middle of the diode which wouldn't go no matter what I did. Seems like the diode's glass actually got fried from the intense light reflections. Not too costly of a mistake but I definitely learned a lesson for life even if it was worth 45 bucks...