The Mysterious case of Mr. 445

I bought a M-140 few days ago. It has been working properly at 600ma (no bigger wall supply) until yesterday. It has suddenly dim a lot. I noticed it while opening the circuit to read the mA in series with a multimeter, but the damage can be previous. It even don´t burn matches. When on, it starts autodim in few seconds and get quite hot. If I let it cool, it starts lasing again (always without burning nothing) and autodims in 20-60 seconds until lets say 50-100mw.

The power supply works correctly and the multimeter says there is 600ma running from the driver (linear, high power) to the diode, so the driver seems ok...

It is mounted on one house as the attached, cooled with a 4*4cm computer type fan, and I have been running it sparely for 30min maximun duty cycles.

Do you have an idea of what´s happening?. Do you think there´s possible salvation? (((

Did the driver short against anything? It sounds like your diode has gone zombie or LED. There's most likely nothing that can be done, unless the driver is faulty.

I'm thinking the same as ARG with a driver short, but if you can try the diode on another driver you'll be able to identify the problem.

:beer:

Most probably I shorted the driver with the screw while trying to adjust the tiny current pot... it makes a lot of sense... sheeeet!. Now that you say that, I think I remember a blue light flash before the dimming.

50€ lesson: do not adjust the driver with the diode wired and the power on :cryyy:

does he have the diode wired directly to the wall wart?

That's what I understood in the 1st post..

In post #4 he said he probably "shorted the driver" so
I guess he was using one.


Jerry

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

well he also said it was while adjusting the pot, might have turned the current too high for the sink to handle the heat and LED

He did say that it starts lasing again after cooling down, so maybe it's just a driver issue. See if you can rig up a cheapo DDL type circuit and see if the laser diode itself is still good.

laserdelic said:

Most probably I shorted the driver with the screw while trying to adjust the tiny current pot... it makes a lot of sense... sheeeet!. Now that you say that, I think I remember a blue light flash before the dimming.

50€ lesson: do not adjust the driver with the diode wired and the power on :cryyy:

Click to expand...

You mean do not adjust the driver without measuring it with a test load.

Strange. I also have a build that auto dims. I thought I was just having bad luck with diodes but from this it sounds like I just need to replace my drivers :thinking:

Im spanish and maybe I mess my explain.

I use a 12v wallmart 600ma connected to a high current (2A) linear (FET/lm358) adjustable driver. While adjusting the pot, the screwer probably touched some other conection point of the driver, shorting it and leading 12v directly to the diode which produced the "flash" of the diode death.

I have some LM317, in the next days I´ll build an express cheapo DLL driver to do an final test with the diode.

Thank you all for the feedback, you are great :beer: