Strange Behavior from P3D RB100

I've had this Fenix P3D Rebel 100 for about a year and a half, I think, and throughout that time it's worked flawlessly, throughout multiple battery changes.

I was outside tonight, heard rustling in the bushes, and whipped it out, clicked on, but no light. I didn't lose any time, but lit it up with the P2D - it was just a rat.

Anyway, I took the batteries out of the P3D and put them into the X5T (poor man's battery tester) and, sure enough, they were very close to completely dead. I haven't used the P3D much lately, but it could have gotten turned on accidentally in my belt pouch and drained the batteries that way.

So I put fresh batteries in and, on all 4 lower modes it works as expected, as well as strobe, but on turbo, instead of the bright constant light it usually is, it's a very fast strobe. I took the batteries out, checked the contacts, put them back in - same thing.

(I've EDC'd this light for a long time, I know how to use it, but to defray the "operator error" comments I'll say again; I know how to use this light. I understand the two modes, 6 outputs, tightening and loosening the head; batteries are not in backwards, contacts are clean, tested with different set of batteries for same effect.)

With the head loosened (low, med, high, SOS) it works properly as always. With the head tightened, the two modes are now fast strobe and slow strobe, with the fast strobe replacing the constant on turbo mode. Or, alternately, when I turn it on turbo, it comes on bright, constant, as it should, but will become a fast strobe within a few seconds. This fast strobe is not the strobe that's built in to the light's UI, that one's still there, this one's separate, and faster.

I tried to take a video, but it didn't come out (crummy camera, I guess).

Has anyone seen anything like this happen before? Any ideas what to do?

(Oh, and always carry a spare flashlight)

I just switched tailcaps between the P3D & P2D and everything worked the same, so tailcap is ruled out as the problem.

it is the tailcap - https://www.candlepowerforums.com/threads/213619

nanotech17 said:

it is the tailcap - https://www.candlepowerforums.com/threads/213619

Click to expand...

I read that thread, and the longer one linked from it, and it may be the tailcap/O ring "leaking" that caused the batteries to drain, but that doesn't explain the strobing, which is my main concern.

I took it outside for more testing, and the fast strobing that's replacing the constant turbo mode is not visible at a distance, but only visible up close, almost like PWM, but way slower than any PWM should be, since it is clearly visible at 10', though not noticeable at 35'.

MedusaOblongata said:

I just switched tailcaps between the P3D & P2D and everything worked the same, so tailcap is ruled out as the problem.

Click to expand...

Pistt!! You didnt even need us. But just in case heres the answer to your problem........ It is the tailcap

I am so smart. Glad its fixed now just to find a new tailcap. Lighthound.com sells them.

hmm :thinking:
I read that "switched tailcaps + everything worked the same" as
--> the "no turbo"-problem still exists with the other tailcap

the "fast strobe" you are describing sounds much like the low battery warning to me.
are you sure the fresh batteries really are fresh?
have you ever seen the warning/do you know how it looks like? on protected rechargeable batteries the warning may only be visible for a very short time just before the protection circuits shut down the batteries.

yellow said:

hmm :thinking:
I read that "switched tailcaps + everything worked the same" as
--> the "no turbo"-problem still exists with the other tailcap

Click to expand...

Correct. The P3D still malfunctions with the P2D's tailcap installed, and the P2D functions properly with the P3D's tailcap installed, so the problem is not in the tailcap.

Did you try tightening the tailcap's retaining ring (inside the tailcap)? Other than that, there are few other things that can go wrong with those tailcaps (unless the problem is the actual switch, of course).

I have this light also and the fast strobe(flickering) sounds like the low-battery warning.

Exactly what type of batteries are you using? Because I've had RCR123(rechargables) that quit holding a full charge and would cause turbo mode to flicker quickly like yours.