my laser keeps dropping voltage! help needed

My 300mw red open can laser diode and 30Ma-1A is acting sooo strange.
every time i flick it on it lazes for like 3 seconds then fades away rather rapidly, im at a loss because i've never experianced this problem before, but i have heard of it. i think it's called voltage dropout?... im not sure but this is what it seems to be doing.

first of all my batteries are supplying a healthy 9 volts to the driver "and no its not a 9v battery and no their not dead, and yes they have enough Ma"

when i flick the laze on the voltage across the BATTERIES drops to around 4 volts, maybe a lil lower.

when i measure the amount of Ma across the diode it goes from 350 down...down..down, and levels out at about 10Ma wich wont even make my open can light up at all.

If someone would be so kind as to give me a word of advice on this matter i would really appreciate it. i DID smell a scent of something like a burnt out capacitor. it could be just me but is that a possibility...the cap might be bad?

Thank you in advance
~Dark

which driver are you using? I think it could be a burnt cap. I haven't seen many 9 volt reds. mine is at 7v at 225ma. but never mind. i just re-read you said open can and 350 mw. so i assume your ma is set closer to 400ma? is it heat sinked good? and just to humor me what mah are your batts?

post edit* to be safe I wouldn't use it anymore until you get this problem licked.

Yes it was at 415Ma for a long time, the driver and module are both heatsinked.

My batteries are a 6V lithium photo cell 800Mah, and a CR123A lithium photo cell, not sure how many MA it has, it is rayovak brand. non rechargable, but its new.

i am using a driver kit that came with a cheap 300mw diode/module, and a driver kit. "i had to build the driver using fairly large parts...looks cheap". but it always did just fine... and last night it was KILLING tape and baloons. now this morning it fades out slowly to almost nothing...but for a good 2-3 seconds it is at whatever power i set the pot to. and mind i did NOT touch anything between the last time i used it and when it didnt work the following morning.

so... are there multiple causes for voltage dropout...or whatever this issue is called.
This is killing me! i've checked the cuircitry for errors over and over and over... the only thing i cant do is tell if the cap is working... i dont know.. im going to wait until someone can tell me whats wrong before i go and buy another kit.

thank you so much for the help by the way, its MUCH apreciated

Tell us more about the driver...

Is it an LM317 based 'DDL' style driver?

Also, it is not recommended to mix different battery voltages. Use the same batteries. If you want 9 volts, use 3 X 3.0 volt CR123 batteries in series.

This may be your problem, that you are mixing a 6 volt battery with a 3 volt battery...
Jay

I understand about the mixing voltage thing, but it worked at 400Ma for over a month.

I dont know what kind of driver it is but i will supply you with as much information as possible...here goes
EDIT:::: IT IS BASED ON THE LM317

pictures:







and the schematic


here is the link to the ebay auction i bought the kit from.

http://cgi.ebay.com/300mW-650nm-Red...5|66:2|65:12|39:1|240:1308|301:1|293:1|294:50

Thanks so much for the help, i hope i can get it up and running again Jay, i'll be ordering from you soon
~Dark

in your drawing it doesn't show the 3v battery. and in the ebay link i didn't see any diodes other than the ld. I think that is of some concern. it looks like you know how to solder n stuff. try going to radio shack and get the parts to make the ddl driver. it is like less than ten bucks. I don' think your diode is dead but i think something is fishy with the driver/battery/batteries combo. sometimes i rant but i hope you see what i am trying to explain.

good luck
michael.

I completely understand what your explaining. the reason the 3v bat is not present in the schematis is because i didnt draw it. it was provided by the ebay seller.

im going to run to radio shack and grab the cap... i think thats it... if not that, then im going to try the transistor thingy. im almost positive its the cap, and i KNOW the pot and 1ohm resistor work, i tested them while isolated.

and i appologize about the picture quality, all i had on hand was the celly.

i'll post back in about 30-45 mins and let u all know how it went.

thanks for the input guys, and i am reverting back to 2 CR123A's. this driver only requires 6v to operate, 3 for the driver, 3 for the diode.

OH! before i forget i picked up a NASTY laser host today for like 7 bucks at K-mart.
anyone ever heard of "NEBO". it was a flashlight with 8 leds and a laser in the center...so naturaly its got enough room for the guts of a laser. drilled out the LED board and screwed in the back of the head of my Aixiz module...just the bussines end. it looks pretty sweet, i cant close up the flashlights battery cap at the end "the clicky button" because i dont have any lithy aaa's yet. only alkaline. its strikingly similar to the pocket pal from jayman. its about 3/4 of an inch longer wich gives you plent of room to work... shit i fit this bulky ass driver into it...and its huge! will post a write up on it in the red laser forums in a day or so.

hopefully you haven't left for radio shack yet go to this link. this is a great home made driver and goes up to 1.5 amps.
http://www.rog8811.com/laserdriver.htm

yeah i've got pretty much the same exact driver, except it only goes to 1A...wich is way more than i need, plus that board is too long to fit in the NEBO host im using. Im actualy done with it! its pretty F'in sweet for a 9 dollar host without a heatsink to match. i'll post a few pics when i do the write up on it. and the best part is theres PLENTY of room for a DDL driver of the same type im using "refer to the photos above" i thought for sure i would need a flexdrive or a lava maybe to get a driver in this baby... but i did it with mm's to spare. so in essence that makes this host one of the cheapest options available to stuff a kit of your choosing into.

and i figured out what was wrong... aparently the 6v photo cell's i bought from radioshack...well they were defective after a certain amount of use. they told me that right off the bat when i mentioned my problem to them. so problem solved. gunna go to batteries plus tommarow and grab 3 rechargable 3.0v-3.7v AAA's to fit in the battery holder that comes with basicly all 8 & 9 LED flashlights that are about an inch thick.

anyways it turned out well, and my problem is solved. who would have guessed it was a defective battery?!?!?!? thank you for the help guys, expect a nice write up tommarow, lata all.
~Dark

......bought that damned cap for nothing... shit and its bigger than the original 25v cap. the one i use now is 35v but taller.

hey you. we did think it was the batteries but you said you for sure had health 9 volts remember.

you said the battery voltage was falling to 4 volts that seems a little low to me, I would be checking for a bad cell, use a power supply to power the driver and see what happens

Best Regards Pyro...