Mitsubishi ML520G71...Red Holy Grail or Flashlight Fail ??

[polishedball]

Could anyone else using the short FL lens from Dave offer any ideas on why I can not get a usable beam at all out of them? I just got the complete Kits in and must be doing something wrong. Also is the Lens dave uses a tiny glass in comparison to the optima Lens that are used in 660 build?

I am just scratching my head going crazy trying to figure out what I am missing, in the pictures you can see the retainers loaded with the glass and also a comparison of what I use for 660 that is much larger on the left (or top in the second pic), the right and bottom being what I just received. Is this lens suppose to be so much smaller? Ideas what I am doing wrong? Is this a diode centering issue when there seems to be a wing on one sided of where the power is? What is the proper way to adjust for center if this is the case?

Thanks ~ it could be a turkey induced coma causing me to miss this but really would like to get it hammered out.

660-635 compare.pngdave lens retainer.jpg

[polishedball]

This is a centering issue as I can start to get it better but what a pain. In my case it is taking alot of force in the up direction while trying to also secure the allen screws. Almost a 2 person job, and when I got height centered left / right is now off. Is there a side by side info of this to the 405-G-2 lens as that glass just goes on and works. These seem to need alot of setup to get correct. Also I seem to have more power loss using this Lens at the same drive current this new lens makes 4 percent less power than the 405-g-2 per my measurements any one else have both lens that can comment?

Could anyone else using the short FL lens from Dave offer any ideas on why I can not get a usable beam at all out of them? I just got the complete Kits in and must be doing something wrong. Also is the Lens dave uses a tiny glass in comparison to the optima Lens that are used in 660 build?

I am just scratching my head going crazy trying to figure out what I am missing, in the pictures you can see the retainers loaded with the glass and also a comparison of what I use for 660 that is much larger on the left (or top in the second pic), the right and bottom being what I just received. Is this lens suppose to be so much smaller? Ideas what I am doing wrong? Is this a diode centering issue when there seems to be a wing on one sided of where the power is? What is the proper way to adjust for center if this is the case?

Thanks ~ it could be a turkey induced coma causing me to miss this but really would like to get it hammered out.

660-635 compare.pngdave lens retainer.jpg

[logsquared]

perfect centering is a must with these wide emitter diodes. I have built some new adjustable mounts that allow centering by adjusting set screws. The new mount also allows for rotating the diode with set screws. Having the diodes perfectly vertical or horizontal is a MUST if you are going to use a higher ratio telescope. And a DOUBLE MUST if you are combining two or more before going trough a telescope. The mounts are .75 X 1.25 X .5 inches. I can post some pictures tomorrow if anyone is interested. Should be about $25 each. I am using these mounts in some kits I will have available soon. I have decided to make a dual with a cube and a knife edged dual with prisms that can be PBS cubed externally. I should have some more info and pics of those module kits in a few days.

[dave]

Yeah, as discussed in PM, its just a matter of centering the diode. It takes a bit of practice, but once you have the diode in position, its not going to move.

This is a centering issue as I can start to get it better but what a pain. In my case it is taking alot of force in the up direction while trying to also secure the allen screws. Almost a 2 person job, and when I got height centered left / right is now off. Is there a side by side info of this to the 405-G-2 lens as that glass just goes on and works. These seem to need alot of setup to get correct. Also I seem to have more power loss using this Lens at the same drive current this new lens makes 4 percent less power than the 405-g-2 per my measurements any one else have both lens that can comment?

[polishedball]

Yeah, as discussed in PM, its just a matter of centering the diode. It takes a bit of practice, but once you have the diode in position, its not going to move.

Thanks Dave a trusty aluminum block and hammer did make quick work of it. However I am combining 2 and noticed the diode hole is not centered in the block. As luck would have it my diodes are 180 degrees out from each other when set to the same height. is this OK still since it is the same pole at that point? going to wave plate one of them then PBS. Thoughts?

[dave]

Yeah, these blocks were made with the intention of combining single mode diodes, so there is a offset for knife edging vertically as well.. Shouldn't matter at all if one is 180 degrees to the other, just as long as both stripes are vertical.

Here is a pic of their intended use, around 1.1w of 637nm

[logsquared]

I'm not trying to start a for sale thread here but these mounts help with the alignment of these (and other) diodes. If anyone needs any send me a PM. If there is enough interest I will start a new thread in the for sale section. Basically, the 4-40 screws around the perimeter allow for X and Y movement as well as rotation of the stripe. After the position is set, simply tighten the screws that hold the diode plate to the body. The adjuster screws can be left in or taken out. The body can be mounted to the baseplate in two orientations 90deg apart. The size without the base plate is .75" X .5" X 1.25". The lens center is .5" from the bottom. There are two 6-32 threaded holes on the bottom .5" apart. The lens thread is M9-.5.
DSC01682s.JPGDSC01683s.JPG

[polishedball]

Curious have you done any diode temperature readings does the use of the 4/40's provide an adequate bridge for cooling to the main block? Neat design, and will obviously make it a snap to center, but at the cost of temp?

I'm not trying to start a for sale thread here but these mounts help with the alignment of these (and other) diodes. If anyone needs any send me a PM. If there is enough interest I will start a new thread in the for sale section. Basically, the 4-40 screws around the perimeter allow for X and Y movement as well as rotation of the stripe. After the position is set, simply tighten the screws that hold the diode plate to the body. The adjuster screws can be left in or taken out. The body can be mounted to the baseplate in two orientations 90deg apart. The size without the base plate is .75" X .5" X 1.25". The lens center is .5" from the bottom. There are two 6-32 threaded holes on the bottom .5" apart. The lens thread is M9-.5.
DSC01682s.JPGDSC01683s.JPG

[logsquared]

Curious have you done any diode temperature readings does the use of the 4/40's provide an adequate bridge for cooling to the main block? Neat design, and will obviously make it a snap to center, but at the cost of temp?

I have not done any formal temp readings with this design. However, thermal resistance is the reason I choose to press in the diodes. The surface area of the mating parts is very large and flat. This should keep the thermal resistance very low. The heat dissipated by these reds is really low. Even if the thermal resistance worst case is 1degC/W at the two mating surfaces the most temp differential will be 2degC. There should be no thermal problems running these diodes at .7A if they are mounted to a large thermal mass or small heatsink with moving air and room temp is around 25deg C. The problem with these and the c@sio diodes happens when the ambient is high. Even a well sinked diode will be over its optimal operating temp before its turned on. If they are to be run at high ambient then active cooling is necessary. If you want I can test the thermal resistance very easily and report back.

[DTR]

The problem with these and the c@sio diodes happens when the ambient is high. Even a well sinked diode will be over its optimal operating temp before its turned on. If they are to be run at high ambient then active cooling is necessary. If you want I can test the thermal resistance very easily and report back.

It is amazing how much of a swing you get with just a few degree starting difference on the 445's and I have seen the same thing with the new 635's.