DVD (22x) Laser diode power up and still not burning or cutting

[kowado55]

I've mentioned the link that has the reference circuit, but anyway, I have re-drew what I've done on eagle, here's the diagram I have sometimes put more 5 ohm resistance parallel to the existing one to allow for more current:

 

[foulmist]

I've mentioned the link that has the reference circuit, but anyway, I have re-drew what I've done on eagle, here's the diagram I have sometimes put more 5 ohm resistance parallel to the existing one to allow for more current:

have you tried a test/dummy load to check the actual current going through ?
have you tried another power supply? I had a similar problem when I began this hobby, turned out my power supply wasn't powerful enough :beer:

 

[kowado55]

I have tried the series of diodes trick and measuring the mV on the series 1ohm resistance (the mV=mA little trick) and it seems fine! I also have a voltmeter accross the diode and resistance, and another ampere meter before the 1ohm resistance to measure the current...all seems ok :undecided:

hmmmm....another power supply this sounds a bit hopeful, but I'm using a normal AC/DC converter with multiple voltages (3,4.5,6,....,12v) settings, supposidly it can handle up to 1 Amp...I'm not sure what else can I try..other than maybe two double A batteries or so!

 

[foulmist]

I have tried the series of diodes trick and measuring the mV on the series 1ohm resistance (the mV=mA little trick) and it seems fine! I also have a voltmeter accross the diode and resistance, and another ampere meter before the 1ohm resistance to measure the current...all seems ok :undecided:

hmmmm....another power supply this sounds a bit hopeful, but I'm using a normal AC/DC converter with multiple voltages (3,4.5,6,....,12v) settings, supposidly it can handle up to 1 Amp...I'm not sure what else can I try..other than maybe two double A batteries or so!

try a volt meter across the 1 ohm resistor before the diode what are you reading (volts) ?

 

[kowado55]

try a volt meter across the 1 ohm resistor before the diode what are you reading (volts) ?

across resistor 0.23 Volts, ampere meter showing 0.28Amps ..difference probably cuz of crappy meter types I guess

 

[foulmist]

across resistor 0.23 Volts, ampere meter showing 0.28Amps ..difference probably cuz of crappy meter types I guess

so 230ma or 280ma .... both of these should work for a relatively bright laser diode....

these diodes you have, might be dead already... I can't tell what's wrong....
try removing the LED and resistor from the circuit, leaving just the laser diode on the output.. same thing?

 

[kowado55]

try removing the LED and resistor from the circuit, leaving just the laser diode on the output.. same thing?

Same thing :undecided:

 

[foulmist]

Same thing :undecided:

if you have an adjustable power supply with constant current control try hooking the laser diode directly to the supply output at the same current and see if there is any difference ... if not you laser diode is already dead

 

[kowado55]

if you have an adjustable power supply with constant current control try hooking the laser diode directly to the supply output at the same current and see if there is any difference ... if not you laser diode is already dead

So I have boosted up voltage and current but not much is happening, as you suggested, I guess this one is fired :cryyy:

I did some more researching and found someone using the same drive that I am using RepRap: Builders: first tests building a powder-based stereolithography printer: part 1 it seems that the optimum voltage is between 2.0~2.5 and current 200~250mA as he suggested... I seem to have exceeded that...many times !

I unfortunately don't have a lab power supply so I can control both voltage and current... even testing with a couple of AA batteries doesn't sound good now as they would add up to 3volts! I need to figure a way to get the mentioned values to avoid frying my second one...!

 

[foulmist]

So I have boosted up voltage and current but not much is happening, as you suggested, I guess this one is fired :cryyy:

I did some more researching and found someone using the same drive that I am using RepRap: Builders: first tests building a powder-based stereolithography printer: part 1 it seems that the optimum voltage is between 2.0~2.5 and current 200~250mA as he suggested... I seem to have exceeded that...many times !

I unfortunately don't have a lab power supply so I can control both voltage and current... even testing with a couple of AA batteries doesn't sound good now as they would add up to 3volts! I need to figure a way to get the mentioned values to avoid frying my second one...!

just make sure you feed it with constant current say 250ma... and it will be fine, :beer:
build a test load and measure the current which you are applying :beer: before connecting any diode

 

[sinner]

So I have boosted up voltage and current but not much is happening, as you suggested, I guess this one is fired :cryyy:

I did some more researching and found someone using the same drive that I am using RepRap: Builders: first tests building a powder-based stereolithography printer: part 1 it seems that the optimum voltage is between 2.0~2.5 and current 200~250mA as he suggested... I seem to have exceeded that...many times !

I unfortunately don't have a lab power supply so I can control both voltage and current... even testing with a couple of AA batteries doesn't sound good now as they would add up to 3volts! I need to figure a way to get the mentioned values to avoid frying my second one...!

The Laser diode in the 24x DVDRW drive that RepRAP: Builders lnk is using is most likely to be a 3.8mm diode (Smaller size red-diode) whereas a 5.6mm (LPC-826) is more common. I too have torn apart several DVDRW's 24x this week and they were all 3.8mm , i extracted all of them and placed them in the anti-static bag so that when i find me some copper 3.8mm Diode mounts/modules i will test on of them and find the absolute maximum currents these can handle.

A 22X laser diode is more or less the same, as any other red when it comes to stability at 200~350mA current.
I've seen 16x LD's go crazy bright at 420mA and still survive.
Although its not much of a rocket science understanding the LD's if u just keep in mind these are "Sensitive" which covers it all..
I am pretty sure if u have kept the LD under 400mA and 3.6V it is still good, but then again "IT IS SENSITIVE TO DUST, ESD, CURRENT SPIKES and WHATNOT"
If nothing works out for you , buy a LPC-815 from any member i.e Ghostchrome has some for sale i saw on his website..
Laser Diodes

if u have trouble extracting them , READ a tad more on that, mohrenberg also made a video as far as i remember.

 

[bloompyle]

The Laser diode in the 24x DVDRW drive that RepRAP: Builders lnk is using is most likely to be a 3.8mm diode (Smaller size red-diode) whereas a 5.6mm (LPC-826) is more common. I too have torn apart several DVDRW's 24x this week and they were all 3.8mm , i extracted all of them and placed them in the anti-static bag so that when i find me some copper 3.8mm Diode mounts/modules i will test on of them and find the absolute maximum currents these can handle.

A 22X laser diode is more or less the same, as any other red when it comes to stability at 200~350mA current.
I've seen 16x LD's go crazy bright at 420mA and still survive.
Although its not much of a rocket science understanding the LD's if u just keep in mind these are "Sensitive" which covers it all..
I am pretty sure if u have kept the LD under 400mA and 3.6V it is still good, but then again "IT IS SENSITIVE TO DUST, ESD, CURRENT SPIKES and WHATNOT"
If nothing works out for you , buy a LPC-815 from any member i.e Ghostchrome has some for sale i saw on his website..
Laser Diodes

if u have trouble extracting them , READ a tad more on that, mohrenberg also made a video as far as i remember.

It could also be a flat red diode. I opened a 22X and found a flat red diode. Also, the only time I've seen a SMOC diode was once from a BDR-205.