445nm dead - a few questions

[isobig]

Hi all - I purchased a 1W 445nm laser from Blord a couple years ago. I used it last about 6 months ago without issue. Yesterday I tried to use it again but nothing, totally dead. I checked batteries and switch (it's a 501b host) and they are good. Decided to disassemble it so I could test the diode with a meter. Got it apart and unsoldered the diode from the driver board. I get infinite resistance with either polarity of the meter. If I recall my electronics training correctly, one way should produce low resistance and the other would be high. I figure this means the diode is bad, but want to check with others here first.

What voltage do these diodes need? I had read somewhere about 5v which I could get from a spare computer power supply I have. Also.. how can I tell which connection is + and - on the diode?

Thanks!

 

[OVNI]

Hi all - I purchased a 1W 445nm laser from Blord a couple years ago. I used it last about 6 months ago without issue. Yesterday I tried to use it again but nothing, totally dead. I checked batteries and switch (it's a 501b host) and they are good. Decided to disassemble it so I could test the diode with a meter. Got it apart and unsoldered the diode from the driver board. I get infinite resistance with either polarity of the meter. If I recall my electronics training correctly, one way should produce low resistance and the other would be high. I figure this means the diode is bad, but want to check with others here first.

What voltage do these diodes need? I had read somewhere about 5v which I could get from a spare computer power supply I have. Also.. how can I tell which connection is + and - on the diode?

Thanks!

If your multimeter uses a typical 3V coin cell to power it, that isn't enough to turn on a Laser Diode. So you can't do a 'continuity test' with them. I don't know all the diodes but from DTR's website two of his 445nm LDs operate around 4V (scroll down to see his test pictures). He also has pictures showing the pinouts.

Now be careful if you're going to try with another 4V (or more) source or battery. A battery could likely fry it (if it's not already fried) by sourcing all the current it can. To properly test, you need to be able to limit the current while applying any voltage. Power supplies that have a current adjustment in addition to voltage like this Mastech can do this.

 

[isobig]

If your multimeter uses a typical 3V coin cell to power it, that isn't enough to turn on a Laser Diode. So you can't do a 'continuity test' with them. I don't know all the diodes but from DTR's website two of his 445nm LDs operate around 4V (scroll down to see his test pictures). He also has pictures showing the pinouts.

Now be careful if you're going to try with another 4V (or more) source or battery. A battery could likely fry it (if it's not already fried) by sourcing all the current it can. To properly test, you need to be able to limit the current while applying any voltage. Power supplies that have a current adjustment in addition to voltage like this Mastech can do this.

Got a lab style power supply and tested the diode. It works! So that means the driver board is bad. Only number I could find on it is TR-0021B . Looks like it is 17mm diameter.

Where can I get one (or compatible), preferably from source in USA ?

 

[OVNI]

Got a lab style power supply and tested the diode. It works! So that means the driver board is bad. Only number I could find on it is TR-0021B . Looks like it is 17mm diameter.

Where can I get one (or compatible), preferably from source in USA ?

Very nice. I was in the same situation a month ago and was happy the driver failed and not the laser diode. Good feeling.

Googling TR-0021B appears to be a buck driver. DTR has buck drivers here. DTR also has a link to Flaminpyro who sells both buck and boost drivers here. For fixed drivers, you need to know/decide what current you want to run the laser diode to place your order. There are also constant current drivers with an adjustable pot so you can set the current level yourself. I didn't see any adjustable drivers on DTR's website but haven't checked Flaminpyro's posts.

 

[Pi R Squared]

You can buy that same driver here: Survival Laser Driver
Be aware there is a known issue with this driver, they can short when pressed into the brass ring and the pill, the one Survival Laser sells has some silicone adhesive covering the danger spot on the driver to avoid this.

Alan

 

[isobig]

Thanks everyone. I will check those links.

 

[Pman]

Do you know exactly what diode it is? I only ask because it matters what you have the driver set too. You could try and contact Blord as I could have sworn someone not too long ago had him build a laser for them. Miss him, he is a great asset to the forum. Bought a few really nice lasers from him before I got into building. He used to build and sell a lot of units and they were high quality.

 

[Pi R Squared]

That driver is not adjustable, it's a 1.25A driver, it's suitable for an M140 or the old A140.

Alan

 

[Pman]

Considering he said it was a couple years ago it probably is an A or M140. It's pretty doubtful it would be an A130 or something else.

 

[isobig]

I did contact Blord here and he has offered to ship me a replacement board at cost. He did mention that he would have to set it for the wattage the laser originally was. If the board is fixed I am not sure how you would be able to change it. I also have no idea how it compares to the one from Survival Laser as far as the short protection mod.

So if the TR-0021B has known issues, is there another 17mm round board that can be used in it's place? I would prefer to have it as reliable as possible.