replacement 808nm diode still can't burn. seems severely underpowered again :(

[cyclonite]

Hi guys,

So I complained to the seller who sold me the 808nm diode in my other thread:

http://laserpointerforums.com/f40/my-ir-diode-dead-77935.html

The seller has sent me a replacement. This time I was very meticulous in ensuring it's properly handled, pressed into the copper module, discharged caps prior to soldering, soldered with low power iron very quickly. etc.

The result, the beam can barely barely leave marks on black plastic when the beam's focused to a tiny spot.

I would rate this beam at below 100mW without a LPM.

Once again, this diode is rated at 1500mW so something is not right.

Here are some beamshots attached again. This time they're taken off a cream wall. Lens removed from the module.

I'm driving the diode at 1.15A. The spec says the typical driving current is 1.2A.

Please help. What am I doing wrong? :yabbem:

Thanks again.

 

[DTR]

What are you using to power it and how have you confirmed the output current?

 

[cyclonite]

Yes I've got a constant current driver, set to drive it at 1.15A. Current output has been verified many times with various diodes. Ampmeter always reads 1.15A through the diodes.

Thanks.

 

[lasersbee]

Have you used a Test Load to adjust your Driver
or have you used your LD as the Test load ???
What is the schematic of the Driver you are using ??


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

 

[cyclonite]

Hi,

OK here's the 'bench' power supply that I'm using:

LM2596 DC 7V-35V to DC 1.25V-30V StepDown Adjustable Power Supply Module LED td | eBay

I also have these:

High Current LM358 Laser Diode Driver (445nm Diodes, Infrared and Red Diodes) | eBay

Dummy load = 3 pairs of 1N4001 diodes in series. i.e. 6 diodes in total giving a voltage drop of 2.1v (assumung 0.7v per pair).

I also have 3 other similar laser diodes that I can use as 'dummy load'.

I could try using the second power supply driver instead, but I don't see how that would help.

Any suggestions?

Thanks in advanced Much appreciated...

Have you used a Test Load to adjust your Driver
or have you used your LD as the Test load ???
What is the schematic of the Driver you are using ??


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

 

[cyclonite]

Ok just as an update, I've used the second driver that I've listed above. I've confirmed the drive is driving the LD at 1.2A and yet the results are the same

Now 2 supposedly good diodes are giving me the same results. I'm wondering if this seller is just selling weak diodes as high powered ones. sigh...

 

[lasersbee]

We are going to need to backtrack a little..

1) in your other thread you state the IR LD in question
was a 1000mW IR LD.

2) now you state the IR LD is a 1500mW LD...
How about a link to the Laser Diode that you bought.


3) the Driver you are using is NOT a current regulated
Laser Driver but a Step Down Switching Voltage Regulated
Power supply that we don't know is properly filtered.

4) if you had run your PS prior to connecting your LD and
you DID NOT short the PS output capacitors before connecting
your LD...you no doubt fried your LD...

I place the damaged diodes on not using a Current Regulated
Laser Driver and perhaps running it on too high a current.


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

 

[cyclonite]

Ok I can help.

Here's the link to the diode:

One extra high burning power (1000-1500mW) infrared TO-5 9mm laser diode + Gift | eBay

It's listed as between 1000mW - 1500mW

I've tried using both Power Supplies. Both links where provided. The latter is current regulated.

Yes I did short the output cap prior to connecting of course. I have built 4 other lasers in the past, 405nm, 445nm and Red LPC-815 so I've got experience.

Thanks.

We are going to need to backtrack a little..

1) in your other thread you state the IR LD in question
was a 1000mW IR LD.

2) now you state the IR LD is a 1500mW LD...
How about a link to the Laser Diode that you bought.


3) the Driver you are using is NOT a current regulated
Laser Driver but a Step Down Switching Voltage Regulated
Power supply that we don't know is properly filtered.

4) if you had run your PS prior to connecting your LD and
you DID NOT short the PS output capacitors before connecting
your LD...you no doubt fried your LD...

I place the damaged diodes on not using a Current Regulated
Laser Driver and perhaps running it on too high a current.


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

 

[lasersbee]

Don't know what else to tell you...:undecided:

Without powering up your LD at a lower current
and testing the output on a Laser Power Meter
there is no real way of knowing how much your
LD is putting out or what its Slope efficiency is
(W/A).
With the Slope efficiency you can tell if your LD
is defective or damaged but that requires an LPM.


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

 

[cyclonite]

ok since I already spent money on everything else and built the enclosure, etc. It makes sense to order a similar diode from a different seller just to hook it up and see what happens. I've found someone in the USA selling one that is rated at 1000mW so it should be a more reliable option to try.

Thanks

 

[Multimode]

Hi,

Could you post a photo of the PSU, driver and diode all set up?

ATB
MM

 

[cyclonite]

not anymore as it's all boxed up nicely in the enclosure. I'm not sure if a picture will help. I've made several other builds successfully.

 

[lasersbee]

ok since I already spent money on everything else and built the enclosure, etc. It makes sense to order a similar diode from a different seller just to hook it up and see what happens. I've found someone in the USA selling one that is rated at 1000mW so it should be a more reliable option to try.

Thanks

I don't understand why a 1000mW LD from another
seller would be a more reliable option...
The problem could still possibly be at your end...:thinking:

I would suggest that if you buy another LD that
you only power it up to 50% of its rated output
BEFORE you pump it with the Max rated current.

And use good anti-ESD practices and a test load..


Jerry

You can contact us at any time on our Website: J.BAUER Electronics