Fenix LD20 issue need help...

Hi, I just bought a semi-working LD20 original version. got an amazing deal from a nice guy

The main issue is that it cannot go into the 3 lowest modes. Every mode is almost the same brightness with turbo being SLIGHTLY brighter. Also, the turbo mode was very hard to engage into (required hard twisting).

I found out that the previous owner kept it in the car and as a result the batteries started leaking... i cleaned up the contact points with a file and now turbo mode is easy to get into.

Still cant figure out the mode problem...everything else works 100% fine...

I heard that using too high a voltage can cause a "direct drive mode" or something that bypasses the lower powers...but I'm using brand new eneloop 1.2v AA's.... I tried energizer alklaline AA's but same thing...


Any help much appreciated this is a great flashlight I want to get it working 100%

Vincent

fi3re I hate to say it but that don't sound good. Do you get the strobe when you have it tightened up and half press? What level are you getting on the loose bezel, do you think it's stuck in med or high? It does not sound like the old simple tighten the tailcap retaining ring fix is going to do much but if you have not already fully dissasemble the tailcap and all it's parts inside including the switch and rubber boot and clean it all.

I hope if you bought this light from someone they told you before the purchase about the leaking battery's if not shame on them.

The simplest and one of the most effective way to clean a battery leak is vinegar, even if you don't see any acid residue left behind it may be worth going back over it with the vinegar one time. If this don't work I don't know what else to say buddy maybe someone else has an idea?

fi3re said:

The main issue is that it cannot go into the 3 lowest modes. Every mode is almost the same brightness with turbo being SLIGHTLY brighter [...]

I heard that using too high a voltage can cause a "direct drive mode" or something that bypasses the lower powers...but I'm using brand new eneloop 1.2v AA's.... I tried energizer alklaline AA's but same thing...

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Here's what 'selfbuilt' said about that. But since he didn't experience that with eneloops, I don't know if this information will help you

https://www.candlepowerforums.com/threads/277658

"There is a quirk in the circuit in 2xAA form – you loose the Lo-Med modes on 2xL91 lithium batteries initially (i.e. Lo and Med are the same as Hi at first). I recall something similar used to happen on the lowest mode of the Olight T25, but in this case, both Lo and Med are affected on LD20-R4.

I suspect this has something to do with the Fenix lights lacking a buck circuit, and the new XP-G R4 emitters having a relatively lower Vf than previous emitters. As such, any voltage above the emitter's Vf will cause issues. Presumably, after running for some period of time, the voltage of your L91s will drop low enough to fall below the Vf of your emitter, and full multi-mode regulation through the boost circuit will be restored. But how long it will take is hard to predict – it depends on the exact Vf of your sample.

Fortunately, this issue is restricted to 2xL91 – rest assured, all modes work as expected on 1xL91 in the LD10-R4."

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