12x DVD Burner: Some Questions

[Marked One]

Greetings to All.

I have recently scored two drives on the flea market for 5 euro apiece. One is a CD writer (can read dvd's) and one is a 12x dvd writer (!!). I plan to use the optical sled from the 12x in conjunction with A lm317 driver to form a factory-collimated labby of sorts. Because of this, I cannot tell you the shape of the diode (LOC, LCC, etc) EDIT: I have opened the sled, and the diode is closed can. I was wondering about three things:
1: What is a safe (100 or more hours until death) current and voltage to drive the 12x to burning levels?
2: Are the losses from the sled significant? Is it worth it to use the internal optics separately?(I have no modules to load the diode into)
3: Is there a shot in hell of there being a visible diode in the CD optics sled?

Thanks, The Marked One

 

[qumefox]

If your cd burner read DVD's, it has a red diode in it. But since this is just a reader, your looking at <10mw out of it, tops.

On the dvd burner. It would probably help if you at least posted the model number of the drive (or better yet, searched for it here) and any part numbers off the sled itself.

 

[Morgan]

^ and photos of the front and rear of the diodes...

M

 

[Marked One]

Thanks for your help!
It seems that the diodes are lcc. After searching the forums, it seems that 250 ma at 3v would be quite a safe current.

 

[qumefox]

Voltage doesn't really matter. Use a proper constant current driver if you want your diode to live a long life. The voltage to the LD will end up wherever it needs to be to maintain the set current.

 

[BShanahan14rulz]

BTW, I think the laser is usually focused a few mm above the output lens.

 

[Morgan]

I doubt these will actually be what WE call the LCC, (long closed can), diode. Most canned diodes look similar but don't be confused by the name WE give them. They may vary in length a little but many canned diodes look the same. WE call the red diode specifically from the GGW-H20L sled the, 'LCC', and that is capable of taking 420mA to give 250mW but I would not suggest trying this through a 12x red diode!

I have not worked with a 12x red diode before and it may be one of the real veterans who can give you proper info. Where did you get the, "... 250mA at 3V... ", info from? Can you give us a link? Just trying to make sure you've interpretted correctly.

Also, to answer one of your original questions. You are likely to lose far too much in the sled optics to make anything useful out of just the sled, (if the diode turns out to be useful at all). BShanahan14rulz is correct that they focus very close to the output lens and therefore you won't get a beam; only a cone of light with a small focused point not far from the sled.

M

 

[Marked One]

It appears that I was overhasty. The diode went LED in about 30 seconds. After having done an autopsy, It appears that it was an open can, short die. The sled proved to be quite lossy, by about 40%. (judging by my 1mw laser pointer). Ah well, now I will try to acquire a 22x, and drive it at 150ma. EDIT: the drive current data was given by niko's diode compilation, and lava's 660nm diode roundup.

 

[Morgan]

What current did you choose? Running a diode in the sled for very short periods, (i.e. just a check to see if it actually works at low current), is generally fine. The problem is that the heatsinking will be limited and any quoted, 'Safe', current we use will likely be twice the current of that in the proper application. You really want to dig the diode out and install it in a module and heatsink.

I've seen figures stating 40% as the measured losses before. How did you work out the losses though? I don't understand how comparing it to your 1mW laser pointer could help. Did you know what the diode was outputting before it LEDed or went through the optics? Did you find the focus was too close to the sled?

Any photos of the diode or sled?

M

 

[Marked One]

I cannot post photos, because my camera is out of commission (dead ccd). I chose a current of 250ma. As for the losses, I can only use my mark 1 eyeballs at this point.:crackup: The diode was outputting enough to smoke tape, when It was at the focal length.

 

[Morgan]

Ok, very trial and error at this point then. Ah, the old, "Mark 1 Eyeball"! A very good all round instrument, that usually come in matched pairs. Are you looking after both of yours? Much diminished usage with only half a set. Not specialised enough for this sort of evaluative work IMO so not really able to accurately estimate through a sled I would say.

The diode is likely to have lasted longer in a module and if it had; was indeed set at a comfortable current and; was smoking tape after the sled optics, then it'll also be more than likely to cut it when in a module.

250mA should give somewhere over 100mW+, (NVM, I just ready the graphs and this should be the case), from a capable diode but it is a huge gamble to assume the type of diode.

Try and get yourself a proper LOC from the LPC-815 sled. Should be less than $10 but about that with shipping. Their known and more predictable.

M

 

[Marked One]

Thanks for the help. I will probably buy a 22x burner this week, and see what happens.
On a side note, can you suggest a way to fabricate a laser module? I have a handful of different lenses, but need a way to house and heatsink the diode, as well as provide adjustable focus. threaded copper pipe, mabe?

 

[Morgan]

The simplest way for the meantime is using a prefabricated one like the Aixiz, (most use these), or a Meredith, (another common one). They cost only a few bucks. It may not be ideal for trying all those different lenses but they come with a reasonable collimating lens anyway and you can go from there.

The diodes we use are usually 5.6mm press fit and there are those on the forum that would produce heatsinks for these that don't require a module, (Flaminpyro, Jayrob, amongst others...), but will likely be more expensive as they are generally hand turned. This still leaves you with the problem of mounting the lens though as the assemblies are available but in limited sizes that may not match your lenses.

Senior members have done lots of research and made great efforts to supply us all with the right lens options so have a look through the trading sections for a reputable seller or go to the likes of Aixiz, O-like, etc to see who can supply them. Limited funds make this a difficult hobby at times but some essential purchases are necessary and a module is one of them at the start I'm afraid.

Best of luck,

M