First build! + colour changing diode??

[Immo1282]

Hi all,

This is my first build-log (of my first build) - Wanted to ask a general diode question too stemming from it.

So the build; I picked the Convoy S2 Host, seen in DrMario's S2 builds (and probably others, but I haven't found them). I started off using the method DrMario tried - gluing the front copper half of one of DTR's 20mm modules to the pill, with a small hole drilled for the leads - while elegant, this solution really needs a round 17mm driver board and is risky with regards to the diode - things are glued together.

After killing a diode, I settled on a different method shown here - trimming the Pill and back-half of DTR's module down considerably and bonding the aluminium rear-module with the pill, then screwing the front module onto the aluminium part's threads. I don't have access to any machine tools, so did this with a hacksaw, files and a Dremel. This is shown in the other attached image.

Assembled as the original host;


Now for the surprise & following question

That's not what I'd expect a 520nm diode (PL520B) to look like - it's a subtly different blue to my 445nm Sanwu - there's less of a violet tinge to the "520" than the 445, and the beam appears lighter in hue. It's a single-mode diode, the beam has a nice clear round dot.
since the can of the diode has no markings one of two things can have happened and hence the question is what's happened? I've got two hypotheses at the moment.

1. I got sent the wrong diode - I don't mind this, as I'll reuse the module which I've assembled. I can always source an actual 520nm module again and build the same way I have with this in this host, and move this diode & driver to a blue Convoy S2 host.
2. Somehow in handling (ESD, heat?) I've warped, or damaged the diode to change it's wavelength? I'm pretty sure this is impossible but I'm still learning...

What do you reckon?

 

[diachi]

You got sent the wrong diode. 520 doesn't even look close to 445. It's traffic light green, whilst 445 is a deep blue.

Good job on the build either way!

 

[Immo1282]

You got sent the wrong diode. 520 doesn't even look close to 445. It's traffic light green, whilst 445 is a deep blue.

Good job on the build either way!

That's what I thought! Learned plenty from it and still have a working laser out of the deal.

Now I'm curious if I can identify the diode I've got here. I reckon it's somewhere between 445nm and 470nm, in a 3.8mm can and is single-mode.

 

[jnrpop]

I would say you got sent the PL450B 80mW 450nm diode by mistake.

Both the PL520B and PL450B are 3.8mm diodes, easy to mix up.

J

Edit: check out the list here if your interested in the different versions

https://laserpointerforums.com/threads/list-of-diodes.100402/post-1472804

J

 

[paul1598419]

Yep, wrong diode. Maybe this will work to your advantage as the seller might not want the old diode back. But, I would contact whoever you bought this from and get them to send out the one you paid for.

 

[Immo1282]

Yep, wrong diode. Maybe this will work to your advantage as the seller might not want the old diode back. But, I would contact whoever you bought this from and get them to send out the one you paid for.

It was DTR of all people - but that's okay, can't fault him (and I don't want to be any more of a problem customer). Lucky I was going to build a single-mode Blue in the Convoy host next year anyway

Enough of a ball-ache for him to figure out if some blue unmarked 3.8mm diodes got mixed up in his supply of PL520Bs that I wouldn't want to start being a pushy customer.

 

[paul1598419]

Oh. Well, accidents happen. I did receive a 445nm diode in place of a 462nm one once, but he got it straightened out fast for me.

 

[Immo1282]

I would say you got sent the PL450B 80mW 450nm diode by mistake.

Thanks - Glad I found out - cause I'm not sure how good it is for that PL450B to be driven at 275mA Time to find the datasheet and see if I shouldn't power it on until I've got a lower-set driver on it.

Edit: Yep - Datasheet max is 125mA, so 275mA is probably not too healthy. Got an LSDE500 that I can substitute to keep that diode alive longer. Driver in this build is the Lazeerer NanoDrive V6 set with fixed resistors at 275mA

 

[jnrpop]

Thanks - Glad I found out - cause I'm not sure how good it is for that PL450B to be driven at 275mA Time to find the datasheet and see if I shouldn't power it on until I've got a lower-set driver on it.

Edit: Yep - Datasheet max is 125mA, so 275mA is probably not too healthy. Got an LSDE500 that I can substitute to keep that diode alive longer. Driver in this build is the Lazeerer NanoDrive V6 set with fixed resistors at 275mA

Hold on, Im not sure DTR stocks the PL450B diode, I can only see the PL5450B diode which is a 5.6mm diode and can handle up to 300mA

I would unscrew the lens and check what size diode you have in there

If it is a PL450B diode, then 275 is abit to high, im running mine at 150mA and getting 110mW with a G2 lens.

j

 

[Immo1282]

Hold on, Im not sure DTR stocks the PL450B diode, I can only see the PL5450B diode which is a 5.6mm diode and can handle up to 300mA

I would unscrew the lens and check what size diode you have in there

Yep - that got me confused for a bit - but it's definitely a 3.8mm diode. Killed a PL520B a couple of months back and it's next to the one in the module as size reference - They're the same package.

I remembered that it's actually a 350mA driver, not a 275 when I measured it - so I'm not going to power it up again with that diode in.
I'll swap the driver over tomorrow so I can still play with it safely. I'll keep the 350mA driver aside for the PL520B

 

[RedCowboy]

I was going to say DTR now has a hollow copper back half for the 12mm but I see you used a 20mm, very nice, I bought some 20mm drill bits to use those modules directly where possible.
I like that convoy host, good choice.

 

[Immo1282]

DTR now has a HOLLOW COPPER back half you can use like you did the aluminum if you prefer.
I like that convoy host, good choice.

The aluminium was nice this time as with my limited selection of tools, I could shape it more easily than copper. Files and sandpaper gum up a lot with copper and Alu is cleaner to cut. Used 20mm modules for this build as the thermal bonding to the case is poor - so to prolong the duty (even though I'm using fairly weak diodes) I wanted to maximise the mass of metal inside the host. Have got a few of the hollow copper modules in 12mm that I'll be using up in future builds though!

I'll get a proper 520nm diode in it soon - I like the singlemode 450 I've got there now but it's not what I envisioned for this build - Blue diode in a green host doesn't sit right with me aesthetically... Good job Convoy make a blue version too

 

[RedCowboy]

Yes I caught my mistake after I took a closer look, the hollow copper backs are for the 12mm modules but not the 20's
I also like to direct fit the 20's where possible, I have learned to appreciate that high quality copper and how it moves heat.

 

[trinh hong phuoc]

A rare flaw, I haven't encountered this when buying, anyway light laser is happy for you, Great start for passion

 

[Immo1282]

Have now completed this with the correct diode - Thanks to Jordan who sent out a new PL520B in an order of some other bits I had placed.

It's a mess inside - but I'm awaiting some spare pills and I've been promised some lathe-time on a colleague's lathe to face down and bore out the pill/heatsink parts properly. Once I have done this, I'll transplant the copper module/diode/driver/spring contact onto a new pill.

Ugly inside but it works and is the first in a collection of these hosts

 

[paul1598419]

That's great, Nick. I love the low power greens as well. As long as the build isn't apt to fail in a way that causes damage to its parts you can get away with it until you have something better.