MicrobeHunter.com Microscopy Forum

I wanted to try an LED mod on a AO 1031 illuminator for my AO series 10 'scope. I was inspired by dtsh from whom I was able to obtain a 1031 illuminator that was missing the special bulb holder for the 6v, 20W halogen bulb. Well I stripped out the transformer and brightness control circuit and went at it with parts suggested by dtsh.

Looking at the spec for the driver (LuxDrive 2100mA BuckBlock A009-D-V-2100) I found that the driver contained its own 10 V reference that can be used for dimming by just adding a 20k pot set up as a variable resistor, 0-20k, 0 being “off” and 20k full brightness. Well, the 1031 has a brightness control pot that is used for the halogen lamp circuit. It is 100k, so I paralleled it with a 25k 1/4W resistor to get 20k and set it up as a variable resistor to get brightness control. See photo. I found that the driver fit nicely on edge to one side of the sheet metal housing, and made a clamp to hold it there. I also added heat sink compound to aide in cooling, though it is only “sinked” to the sheet metal housing.

The LED I bought from LED Supply, Cree Xlamp XM-L2 in neutral white 4000K, 1000 Lumens at 3000 mA. The LED is mounted to an aluminum slug to which I attached a copper fin for added cooling (Copper is ~40% better thermal conductor than aluminum.)
To top it off, no pun intended, I had a small 12V fan from a PC motherboard, so I mounted it to where the original dimmer control circuit had been. It is an Antec ball bearing fan with mounting holes 1.25 inches on center. I installed it just to keep the air moving somewhat. A 100 ohm 1/4W resistor in series slowed it down so there are no apparent vibrations from it, but it still keeps the air moving.

The power supply is a $12.00 12V, 6 amp brick I got off Ebay, which works quite nicely.

The unit is supper bright compared to the 20W halogen. It is good to have the dimmer control as well as the neutral density filter that is standard in the 1031.

It was a fun project, and I hope it gives others some ideas.

Nice! I am using an essentially identical setup in my gem scope. It really is wonderful how easy to buckblock is to integrate and how bright and cheap the XML2 is. The visual impression is really pleasing as well. I found it did eventually warm up the piece of aluminum I used as a heat sink if left on for hours, but not much (especially compared to how hot it would get with the original halogen that was included), and that's in an enclosed base.

Edit: meaning to ask, do you get a bit of doming at lower mags? My copy did a bit, wasn't sure if it's universal.

Scarodactyl wrote: ↑

Wed Oct 19, 2022 11:17 pm

Edit: meaning to ask, do you get a bit of doming at lower mags? My copy did a bit, wasn't sure if it's universal.

Sorry for the delayed response, but I didn't notice your edit. If by doming you mean having a brighter center spot at the lower power, the answer is yes, until I moved the LED closer to the lens. I had to make a spacer to put the LED in the same location as the original halogen filament. I originally had it too far back. That seemed to even out the lighting. I also found that running the LED at 25% current at maximum was still plenty bright, so I dropped the resistor/pot down to 5k. I get no heating at that level of current and still have to run at a lower intensity and use the built-in ND filter. Those LED's are extremely bright!!

By doming I mean distortion that makes the center of the FoV look higher than the edges (ie a coin looks more biscuit shaped).
That said the additional detail about the illuminator is interesting and appreciated.

Gerry, Thanks for that informative post. That looks like an excellent installation, particularly the dimming implementation.

Scarodactyl wrote: ↑

Fri Nov 11, 2022 1:36 pm

By doming I mean distortion that makes the center of the FoV look higher than the edges (ie a coin looks more biscuit shaped).
That said the additional detail about the illuminator is interesting and appreciated.

None that I have noticed with any of mine. On the 10 there's a frosted lens just after the bulb/LED ("modified Koehler") so provided the light is positioned to fully illuminate the lens it *should* be fairly even illumination.

Scarodactyl wrote: ↑

Fri Nov 11, 2022 1:36 pm

By doming I mean distortion that makes the center of the FoV look higher than the edges (ie a coin looks more biscuit shaped).
That said the additional detail about the illuminator is interesting and appreciated.

I went back and checked and find no doming. I even made a very tiny disk to examine and found it to be like the biscuits my wife makes, just perfectly flat. (Maybe I shouldn't have said that?)

Nice post. Thanks. I need to do something similar to this with my Nikon OptiphotPOL.