How to improve electrical contact on the ThruNite TN30 / TN31 battery carriers...

I noticed that my replacement TN31 started to develop some intermittent flickering on some of the modes, didn’t seem to be anything related to the driver so, I decided to investigate a little and disassembled the battery carrier and found that the center positive contact button (+) which is actually a screw tends to loosen up after some use.

Since I had already disassembled the battery carrier I decided to polish everything up using Flitz, here are some before and after pics, the difference is noticeable.

Original as received from ThruNite

After polishing with Flitz, a rag and some Q-Tips,

I lapped and polished the center positive contact button too then screwed it in tight using pliers

Apparently this is what causes most of the flickering, you tighten the screw by holding it with pliers and twisting it to the right as in the picture, tighten both screws on each end of the battery carrier.

Some more pics

I finished by applying pro gold on every screw and electrical contact on the carrier, tightened the center button using pliers and made sure all screws are nice and tight.

Flickering is gone and it lights up like a champ on first click no mater which side of the battery carrier is facing the lamp (The one with one spring or the one with 2 springs)

Hope this helps anyone having trouble with the light.


I did the exact same thing, although I didn’t have a flickering problem.
Did you also do the contact plate in the head ? It’s really easy, you just need to find a small enough philips screwdriver so you don’t strip the screw head when trying to remove. Once I removed the plate, I polished the top and bottom and installed it back. Could be my imagination, but it seems brighter to me.

That is what I plan to do next, but was going to go to sears to buy the right screwdriver for the job, is there any perils to watch out for while doing that?

The one thing I didn’t do is polish the sides of the plate.
Wasn’t too sure if that would eventually lead to a shorting out problem.
I notice it does seem to touch the walls of the head.
It appears there is a small amount of play, it’s not self centering when you torque down the screws.
I just wanted to be cautious.

Great idea. Thanks for posting.

progold is 25 bucks a pen. Where did you buy yours?

Looks VERY shiny.

If it makes it brighter - and not just a placebo - I might be tempted to do it!


I found the screwdriver to open the head plate and proceeded to polish both sides, specially to where the plate contacts the driver board and where the battery carrier touches the head plate, then applied pro gold to both sides to ensure great electrical contact and re assembled.

makapuu, I don’t think its your imagination! I also notice the light to be a bit brighter now! :bigsmile:


Wow that is expensive, I bought mine for like $5 at fry’s a couple of years back, they were on special.

DEOXIT also ensures total conductance

Yup, I first polished, then cleaned with contact cleaner, then deoxit, then progold

DEOXIT is ace stuff, pricey but does what it says.
I use this on various bits on cars, especially the door pin switches, saves any hassle at all with bad contact.

I didn’t disassemble the carrier but I used a polish like Flitz, cleaned both ends and the center contacts, wiped cleaned and finish cleaning with a little isopropyl alcohol. Light works now with carrier going in either way. Thanks AlexGT.

Had to break down and order some Flitz from eBay. I have a tube somewhere in the garage but after 2 hrs searching for it I gave up. I’m sure it will show up the day after the new tube arrives.

I took the battery carrier apart. I polished all the contacts, tightened the screws… Put it back together & no issues at all. I slapped it , shook it…. It didn’t flicker once. Plus… I didnt lose one screw… think my wife is impressed! LOL… Appreciate the help! :smiley:


Glad to hear it went well Dale!

I was having technical difficulties… Didnt think it posted.

Mine also flickers, so I cleaned and polished the whole battery assembly. Also found oil under the battery plate at the screws. No more flicker, thanks AlexGT.

I'm a pretty cheap guy overall and I don't buy the expensive stuff. I just polish the surfaces with an eraser and rub the pencil lead on them. I Know, but it does work. The expensive stuff is a lot better, but I'm too cheap to buy it and this is a cheap alternative, (I should say budget alternative).