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Blu-ray cutting out problems

M

member02

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I just finished assembling my first blu-ray laser, i've got DDL's lm317 circuitry going on, using 32ohms between the resistor and pententiometer to reach lasing threshold at 37ma-42ma.

The problem: Laser is flickering pretty bad, and turns off sporadically after being turned on for several seconds

I'll attach a picture and a video later... working on a new circuit in case I messed something up.
 





M

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YAY!!! i have a working bluray!!! after two failed reds!! hahaha!

turns out, the Violet lead was Partially touching the Irfrared Lead, and evidently it was switching back and forth, took my friend here a KEEN eye to see that faint red light on the paper.


So, I thought this diode would die if say the red and blue were turned on at the same time? well, apparently it will just switch around between the two, weird eh?

pics lata.
 
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LarryQ

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Just a suggestion...before you smoke a Diode....

Re check your current with a 1 OHM sence resistor..

If you still have it set to where it was going between BOTH the red and Violet..then you may be way overdriving the Violet now that the red is isolated!

Not trying to be a Know-it-all......just trying to be helpful and keep another 405nm diode alive!!!

Congrats on the new laser..

Really nice color isn't it!!>!>!??

LarryQ
 
M

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oh no, I checked and doubled checked.

After isolating the red from touching the violet, with epoxy, I finally double checked everything, it seems the blu-ray lases at 37-39mA and I'm running it at 39mA now, it's probably already had a couple hours run time :D lol, it's doing great, as bright as the 5mw red lasers i have, I love it!
 
Hemlock_Mike

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Member02 --
Another success story. I'm running 39 mA too and getting 10 mW output.
Not a show off green but a home made blu which can find fun things which glow !!

Mike
 
M

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i love it! ;D

everyone is bedazzled by this color laser... and it's weird, its such a deep violet color that you can't easily focus on the dot with your eyes when it's more than a couple feet away, it's as if your eyes can't focus because the light is inbetween nvisible and ultraviolet, word.
 
M

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oh noes!

I've sucessfully made three of these based on DDLs driver using typically 25ohms with each with 25ohm Pot from ratshack

BUT, the last one I put together, normal like the other two, started to get BRIGHTER all on it's own!!!!!
I was scared to turn it on, but it basically looks like more than twice as bright as the other two blurays AND is starting to FLICKER a tiny bit!!

What should I do?
 
Gazoo

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Maybe you have a flaky pot..I assume you are using the 25 ohm 3 watt rheostats?
 
M

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yes, it is the 25ohm rheostat from ebay. I am going to measure the resistance later today between the pot and see if it's working.

Thanks for the thought, I kind of figured it had to be something in the resistor area of the whole circuit, everything else is solid.
 
Gazoo

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I meant the ones from Radio Shack. Do you have a link for the ones you got from ebay?
 
M

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yes, it's the radioshack one that everyone knows.

the post above was a mistake, I have ebay ones, but have not yet used any of them, plus the ebay ones are 100ohm tiny things.
 
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member02

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the Radio shack Rheostat measures between 0.04ohms and 24.7ohms, nothing seems to be wrong here!

but lemme check the built in resistor... is steady 33.0 like I thought...

weird, i don't know what's wrong here... I'm afraid to turn on the thing, because it was WAY too bright compared to the other blurays I made, and the rheostat didn't have an effect on the thing at all...


after checking the rheostat works ANd the resistor works, I decided to turn on the laser: Viola! it work, and is adjustable... BUT after about 15 seconds it started flickering, so I started turning it down, but the rheostat didn't seem to affect the flickering (the flickering is brighter than anything else...)

I'm wondering if it's touching the leads of the infrared just like the one mentioned in the original post?

I started doing a detailed inspection: the negative lead joint from LD- to bread board was attached by a single point of solder... upon touching it, the LD- lead broke off easily... might be the culprit, checking...
 
M

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nope, that's not the problem, okay, time to dismantle the bluray and check the circuit with dummy load.
 
M

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on the dummy load:

the sense voltage measures 0.01-3 (varies - probably the cause of the flickering?), and nothing else registers for some reason, I get 0.00 across the 1ohm resistor, and nothing across the diodes... is my lm317 bad?

resistor and rheostat are both working fine, I checked them several times

the battery is 8.93 strong, wiring double checked again, nothing wrong... how can I check the silicone diode and the capacitor to see if they are ok?
 
phenol

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use your DMM's diode check function. It pumps a fixed current thru the diode /typ 1mA/ and measures the drop across it. for normal si diodes the fwd drop should be anywhere from 0.55 to 0.7something volts. 1N400x are in the 0.5x range at 1mA.
as regards C - capacitance meter. some dmm's have Cap function.
 
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