Dvd burner LD problems

[liukthebest87]

Hi all, this is my second thread in this forum (after presentations) and first of all excuse me for my english!
I'd like to know why i broke all lasers that i try to build..
The last was an LPC-826 (i think, harvested from an LG GH22NS50).. I read a lot of threads in this forum and saw a lot of videos on youtube, so i put the diode in an aixiz 12x30mm module with thermal paste and i connected it to a lm317 driver, setted with 200mA safety current (i read a safety current for lpc diodes is of about 410mA).
After putting the module in a homemade heatsink, i tried to switch it on and it was working. A match didn't light. So i switched it off, set the driver to 210mA (with a test resistor) and i tryed again. I think it worked for 10 minutes (continuos) and the heatsink was cold; then i decided to stop trying and close the box with the poor 210mA current (because, without explanation, in the past i broke an LPC-815 with 250mA mounted in the same module). I turned it off, i disconnected the amperometer and i solded the positive wires each other. After that, i tried again and the diode was emitting a weak red light, like the old LD i broke. :cryyy: i'm desperate... i broke about 6 LD in the same way (16x dvd burner lasers with only 110mA-120mA current)..
What's wrong?!?!

 

[Sigurthr]

Well, it could be something as simple as ESD (electrostatic discharge) blowing up your diodes, "LEDing" them. It could also be that you cooked the diode when soldering. If your driver has a capacitor on the diode side of the LM317, not discharging that before you disconnect or reconnect the diode could also kill it.

Did you use any clamp on heatsink on the diode pins when soldering? How long did it take you to solder the diode? You should never spend more than 2 seconds touching the diode's pin with the soldering iron, and always use the lowest setting possible to melt the solder.

Did you have any static protection while working with the diode (including soldering)?

If there is a capacitor near the diode, did you discharge it before changing your setup?

 

[Blord]

Did you look for possible static electrical discharge somewhere on the worktable ?
Dry air, wool cloth or electrical equipment that aren't earthed to ground.

LPC-826 shouldn't go death with 210mA current.

 

[weeba2kv]

Time to click Welcome to O-like,the source of good quality laser products at unbeatable price and perfect service !

 

[liukthebest87]

Thanks for the answers!

Did you use any clamp on heatsink on the diode pins when soldering? How long did it take you to solder the diode? You should never spend more than 2 seconds touching the diode's pin with the soldering iron, and always use the lowest setting possible to melt the solder.
Did you have any static protection while working with the diode (including soldering)?
If there is a capacitor near the diode, did you discharge it before changing your setup?

I think the soldering is not the problem, because i solded with a 15W soldering iron less than 2 seconds; i have solded 2 wires to avoid touching more than one time the pins with the soldering iron.. it was working till i solded the positive wire to the (long enough) wire connected to the positive pin of the LD!
I was wearing jeans and cotton sweatshirt and to avoid electrostatic discharges and i whenever touched ground before touching the wires.
The only thing i never do, is discharge the capacitor before changing setup :thinking:

Did you look for possible static electrical discharge somewhere on the worktable ?
Dry air, wool cloth or electrical equipment that aren't earthed to ground.

Only now i am thinking that the building where i worked has no earth wire... maybe the soldering iron injects a current when i close the driver circuit soldering the positive wires??:thinking:

 

[Blord]

Because you lost already 6 LD in the same way I would seriously consider a hidden ESD source.

 

[liukthebest87]

Because you lost already 6 LD in the same way I would seriously consider a hidden ESD source.

That's possible, but when i said "the same way", i did'n mean that they breaks in soldering procedure, but i mean that the current wasn't high enough to kill a LD and the diode died in the same mode ("LEDing")..
Nex time, shorting the pins of the LD when soldering the wires should protect it from ESD.. is that correct?

 

[liukthebest87]

Finally i discover where was the problem! I tried another time with a dvd burner LD token without paying from the trash of a store.. The laser is still working at 200mA: i have only shorted the capacitor before changing setup! Maybe that was the problem! Thanks to all!
Now, i have another question: if i have a LPC 815 diode, can i test the driver with a standard dummy load for red diodes? (4x 1N4001+1ohm resistor)

 

[123splat]

Sig asked it and you admitted that you DID NOT do it. EVERT TIME YOU DISCONNECT THE LM317 DRIVER FROM THE LD AND POWER UP THE DRIVER TO SET THE CURRENT, YOU M U S T DISCHARGE THE OUTPUT SIDE CAPACITOR BEFORE RECONNECTING THE LASER (you discharge the capacitor by:1) remove power source from driver, 2) short the driver output wires (LD+ & LD-) together for a second or two).

 

[liukthebest87]

Sig asked it and you admitted that you DID NOT do it. EVERT TIME YOU DISCONNECT THE LM317 DRIVER FROM THE LD AND POWER UP THE DRIVER TO SET THE CURRENT, YOU M U S T DISCHARGE THE OUTPUT SIDE CAPACITOR BEFORE RECONNECTING THE LASER (you discharge the capacitor by:1) remove power source from driver, 2) short the driver output wires (LD+ & LD-) together for a second or two).

Yeah that was what i did this time I hope that my bad experience will help noobs like me What about my last question? I'm asking it because of the LOC diode's "differences" (different I/O characteristics, treshold, etc ??)

 

[billg519]

You could put a resistor of a high value (say 1k) across the cap. This resistor is high enough in value to not affect the driver, but it will drain the cap and hold it at 0 volts when the laser is turned off. A charged or partly charged cap kills the diode with a high current pulse when you solder the diode in place.