Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

Buy Site Supporter Role (remove some ads) | LPF Donations

Links below open in new window

FrozenGate by Avery

Learn From Mistakes That Can Happen To Anybody...

I was repairing an oscilloscope with a broken power supply. It's a very old switching power supply, but without a resistor draining the main capacitor. I left it on my desk unplugged, and after a while I decided to move it, I couldn't find the fault. I grabbed the power supply and was zapped. It was minor, afterwards there was still 300V in the capacitor. The rest apparently discharged through my pinky, according to the two white spots that match the pin distance of the cap. It doesn hurt a bit, like I burnt it.
This is my second "first hand" experience with high voltage, my first was my orther pinky, I didn't isolate the mains properly. But I'm the most concerned about the nitrogen laser I want to build, at several kV there's no room for error. My first attempt to build it was very carefull, this reminds me to keep it safe.
 





On a related note, Bluefan,

I had a half-charged primary capacitor from an older CRT TV PSU discharge in my hand. I threw the screwdriver somewhere on the other side of the room.

Another time I shorted another cap with a screwdriver. Big muthafukka, 400V and 2000uF or something. Made a bang loud as a handgun. Scared the cr*p out of me.

Word to the wise, don't mess with capacitors. Them muthafukkaz ain't playin' nice.
 
I shorted the cap after I got zapped, made quite a bang, even though it only was 100uF (still 13.5J). I'm now soldering a resistor across the cap, but before that I shorted it just to be sure. And it made a bang again, not very big but still more than expected. Lesson: keep caps shorted and make sure there's a draining resistor.
 
Bluefan said:
Lesson: keep caps shorted and make sure there's a draining resistor.
Click to expand...

DSC_7054.JPG


Oops. At least they never bit me. :yabbem:

-Trevor
 
I've only heard of high voltage caps (kilovolts) getting some of their charge back, in my case I probably didn't drain the cap fully when getting the first loud bang. Still, a shorted cap is a good habit.
I also measured at the live circuit, but I was very cautios when doing that, when a circuit is live you're more aware of the dangers.
 
one lesson i have had was with the dragonlasers spartan 1w. i was messing around with it without safety glasses on (big mistake). i hit a mirror on accident and the beam hit about an inch from my eye and even then i could not see for a good hour. ALWAYS wear safety glasses
 
If you can't see for an hour I'd really check if you haven't got any permanent damage.
 
i agree however my vision returned and my vision is the same after a year. im sure itll haunt me later as it would be permanent. i think your right though because my right eye recently went from 20/20 to 20/30 my left is still 20/20. but i am right eye dominant.
 
Re: Mistakes That Can Happen To Anybody...

Tech_Junkie said:
Not sure, but other people have said it happened to them also, they just didn't put 2 and 2 together. IgorT also advises not do it, and he obviously knows what he is talking about. I guess you just got lucky.

It might be heat, or a reflection. I think it depends on how the laser is focused at the time. That's why it doesn't happen to everyone. This is only a guess.
Click to expand...

I to have done this once or twice and all seems well with the laser just as if it never happened
 
Don't have a 1watt 445 in your hand when you put your safety glasses on you just might blind someone behind you...like my girlfriend!!! She's ok but got yelled at!! Now I make sure I already have them on before I turn it on.
 
People dont realize the power these lasers put out. You really have to treat them like a gun. Make sure you know what you're pointing at before pulling the trigger, and handle with extreme care.
 
Yeah no kidding!! That happed when I first moved in with her so used to being by my self with my lasers..forgot someone else is in the house now..I'm way more carefull now.
 
Apparently it's common knowledge that the PHR-805 is a case negative diode and that the Micro-Boost driver is probably not the ideal unit to drive it, except TO ME. After years of service my ONLY laser project to date, a beautiful stainless steel CREE C3 with a PHR-803T, went LED on me. It was a slow painful death of gradually dimming over a course of months. I labored over the innards to see what was wrong and in the process, fried the FlexDrive V4 that drove it.

Needless to say, it was time to resurrect this beauty. It had been awhile since I was on the LPF, let alone BUILD another laser, so I decided to give it a crack at it again. For some reason I purchased a current-preset Micro-Boost drive instead of a Flexdrive, and I also purchased a new 405nm diode. I skimmed the Micro-Boost manual just to see the solder pad layout, but I didn't read any further. I was also oblivious to the change of guard from the PHR-803 to the PHR-805. I just thought I could solder it up, drop it in, and be on my way. I was wrong.

After putting it together, I clicked the switch and got the same dim light from the diode like I did from the old dead diode that I just replaced. "WTH?" I thought. I went to this forum and found that had I RTFM, I wouldn't have gotten into this mess. I was applying incorrect knowledge for this application. In had connected the case pin and what I thought was the (-) cathode pin together on the diode (-)OUTPUT of the driver, just like I did with the PHR-803 years earlier. I had also helped kill things by assuming that there was a common ground across diode, battery, and the driver circuitry. I found out that is NOT the way to incorporate a Micro-Boost driver into a build.

Taking my lumps, I took what I learned and went forward. I ordered a new diode and assembled the laser the right way. I soldered the case pin to (-) DRIVER OUT and left PIN3 disconnected. Anode is soldered to (+) DRIVER OUT. (-) DRIVER IN is supplied by a wire that contacts the tailcap switch through the flashlight body. (+) DRIVER IN is through a contact spring. The laser diode casing is electrically isolated from the flashlight body by being mounted in a non-conductive heatsink. After assembly, the laser works beautifully.

The moral of the story: RTFM if there is one, and research, research, research. If lost, seek the wisdom in this forum...after a thorough search, of course.

I drew up some diagrams of the failed model and the working model:



phr2.jpg



phr1.jpg
 
Not really related to lasers, but will definitely make you do a "pre-flight" check no matter what your playing with. I had a Raptor 70 rc helicopter and purchased some cheap 2.00 servos off of ebay, I unplugged a servo on the heli so I could plug these in and test them. The next time I went out to fly the 2K dollar chopper, it lifted off and did a nice arch to the right and hit the ground upside down 50 feet from where it started. Luckily it only did about 400.00 damage to it.
 
You must log in or register to reply here.





Back
Top