Re: FS: Key Chain CR2 Kit! - SCHWEET!
Hmmm... that's very interesting Igor.
I have only been through maybe 12 or 15 GGW's, but I have never had any that were really low output like that.
Only about 180mW' At 190mA's (AixiZ acrylic) is about the lowest. But some were much higher efficiency!
Yes, see, but i know where those diodes came from, and among them were many v3's (arbitrary numbering system we made up with Dave to separate the three different sled versions). Unfortunatelly, there were no v3's in later batches...
Only v2's are left..
The v3's were the super- and mega-freaks -
without exception, every single one peaked between 215-236mW after plastics. They had a pot that regulates the current set way lower than v2 sleds! The v1's, i don't remember, i should check my notebook. But i think they were also good. The v2's on the other hand were the most numerous... At least in my case.. I don't know what kind of mix you got at that time, but maybe you were lucky. Because the v2's are all over the place.. There are freaks and super-freaks among them, many "normals", like my first GGW was, and then also many lower efficiency ones.
But the datasheets in their slope efficiency Min. Typ. and Max. ratings show variations even higher than what i'm seeing here! So technically speaking, the diodes still are up to specs! Even the lowest efficiency ones!
With small samples, statistical anomalies appear quite often.
But with a big enough sample you always get the same picture.
Just out of curiosity, since you go through so many diodes. May I ask what method you use for removing the ribbon?
I have a theory that some diodes get damaged (or weakened) from using heat to remove the ribbon cable. But I have no way of proving this. Except that I have always had very consistent results with most all diodes, in clipping the pins clean with fine snips...
We discussed this once before, when i was posting PHR efficiency data..
I told you what tools i use to remove the PCB/ribbon thingy back then.. :yh:
Check out the attachment..
This is how i do it:
- I set the digital soldering station to 330°C, as per the diode manufacturer's specifications (3s of soldering allowed at 330°C, 1.5mm from the base of the diode - say the datasheets).
- While the soldering iron is warming up, I cut as much of the PCB or ribbon off around the pins and between them with the diagonal cutting pliars (on the left in the attachment) as is possible, without bending the pins... I try to separate the ribbon pieces from each other, so that each pin has a tiny piece left over.
- I remove the remainder of the ribbon downwards by separating it from the solder blob with a fresh surgical scalpel (on the right of the attachment), and in some cases i have to remove some solder with the scalpel as well, cutting between the solder and the pin to release the ribbon from the pin if it won't separate the usual way...
- In the end i just swipe the leg quickly to get the remaining solder off. This swipe takes less than a second and removes all solder. The diode is in a heatsink from the start... The previously separated ribbon pieces then just fall off the pins by themselves.
- During this entire time (and whenever i'm handling diodes obviously), both me and the soldering station are grounded.
Trust me, after almost 12 years of working with electronics, i should slowly know how to solder safelly..
But when it comes to expensive diodes, i am infinitelly more careful, than when i'm soldering ICs to PCBs for example...
Wait, wait! The pre-testing is done in a different setup! There i don't even remove the ribbon! I just solder to it! That's where i got those ridiculous numers from! Before the ribbon was even removed. But those ultra lows are luckily rare, however even the 200mA/170mW ones can die after only a few hours of use... (That's why 180mW is my lower limit - they already fall under the "normal-efficiency" category...)
The above procedure was describing the after selection stage - when i'm cleaning the diode assigned to a laser, already installed in a Heatsink/Module, so i could solder it to the driver... I determine diode efficiencies long before removing the ribbon.
EDIT: Oh, and i have two of those diagonal cutting pliars (is that what they are called?) One is for rough work, where it gets damaged, the other is for undressing diodes ONLY, so it doesn't lose it's edge... The sharp one is marked with a thin piece of blue electric tape on the inside of the left handle. You can even see it slightly in the photo...
EDIT EDIT: I have a theory on why some diodes have such a low efficiency. These are QC-Reject sleds. Some get rejected due to broken parts, lenses etc. But others MIGHT just get rejected due to the diode not being up to specs - not providing enough power to do the burning at the desired speed...
Maybe a part of the rejects are rejected for this reason, and they end up on our forum...
But i've heard from several people complaining that the GGWs are sometimes way low in efficiency by now. People, who just buy one or two, can either get very lucky or very unlucky. It's completelly random. I bought 78 diodes in two purchases and now 10 more, and i get to see all types. Luckily the really bad ones are in a minority... But it still bugs me!
I really need to test the Vf theory! Maybe i'm onto something there, and if so, those diodes could still be used. Even for high powers! Theoretically, they could even be tougher, by some random fluke during die growth... But this is just something i want to test one day, so at least i put the "weak" ones to some use...
