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Discussion Starter · #1 ·
When I bought my NDM86 last year it came with two early 4X POSP scopes that take the now defunct short 2.5V battery. There are lots of ideas on what to do to replace the batteries, I decided to use two standard 357 1.5V watch batteries. I turned a plastic adapter on the lathe that fills the void between the compartment and the new batteries which keeps the new batteries centered. I also needed a conductive spacer the size of another battery so the contact in side the cap would touch the battery stack. Rather than getting fancy with the spacer I cleaned up 4 copper pennies then punched out a 7/16" OD slug from each one. The 4 slugs stacked were the perfect height.



I figured out that the Russian wiring had the negative at the bottom of the battery well and the positive at the cap.



I stacked the penny pieces on top and put the cap on.



So after all that the damn light didn't work. I couldn't see a filament using a magnifying glass so I tested the bulb with a meter and sure enough it was blown. I grabbed anther bulb out of the case and it was obviously bad with a foggy glass bulb. The third bulb I retrieved was fine so I put it in the scope and couldn't tell that it was doing anything so I removed it and checked it with a pair of batteries, it was lit but dim as can be.

I hate to throw anything useful away so I took the old bulbs apart. A soldering iron on the back of the brass holder released the bulbs cathode and it pulled right out. The anode was soldered to the brass insert the bulb was inside and there is an insulator between the insert and the retainer.

 

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Discussion Starter · #2 ·
Naturally I figured that an LED would be the best choice for a replacement so it was off to Radio Shack where I bought a 20 piece variety pack of LEDs for $4.84 with tax. I soldered the anode of the LED to the inside of the insert then trimmed it off. Then I slid the insulator back onto the insert.



I cleaned all the waxy crap out of the retainer and slid the LED cathode through the hole in the back of the retainer and soldered it in place.



The hardest part of this whole project was getting my cheap camera to get a shot of the result. It's not fuzzy in real life, stupid camera wouldn't focus!:



It worked out so well I made a green one too.

 

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Fantastic work and post. Thank You for sharing this! :beer:
 

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Damn fine work! You do know that you can just buy LED's from Kalinka optics though don't you? They are more expensive but much, much less work! Still, kudos to you brother!!
 

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Should be a sticky.
 

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Discussion Starter · #6 ·
:D I looked on Kalinka's site last night and didn't see any LEDs. It takes 10 minutes to make one (no shipping charges either) and I got 20 LED's for <$5 and used 2. Now I need 18 more projects!
 

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A lot of win there. Nice work and creativity....:thumbsup::thumbsup:
 

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Discussion Starter · #9 ·
Thanks everyone!

I should mention that the green LED seemed kind of weak to me, the color was no where as intense but it still lit the reticle plenty for low light use. I just noticed on the package the LEDs came in that the small red and yellow LEDs have an intensity rating of 400~800 and the small green ones are rated at 200~400. It doesn't way what the "intensity" is measured in so just take it that the green one is half as bright.
 

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That's pretty dope!
 

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thanks for the write up,,,,,I have used nickles and hammered muzzle loader balls and buck shot to adapt batteries
 

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WOW, amazing work my friend. Had some thoughts/questions PM sent
 
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