Flashlight malfunction. Only works once per battery cap tightening

[andygold]

I know the title wasn't really describing the issue...

I have a relatively old Utorch UT01. A longtime favorite of mine and no longer available.

All of a sudden yesterday it started to malfunction. When I try to turn it on, if it does light up, once I turn it off I cannot turn it back on again unless I unscrew the tail cap and then tighten it. It will then turn on no problem, but once again only once. So every time I want to use the light I have to unscrew and then tighten the tail cap.
I took an eraser and cleaned the battery contact in the head, the threads at the tail of the body, the very back ring of the tube, the mating surface in the tail cap, and the spring. I also swapped over to a different 14500 cell, and the same issue still exists. Thoughts?

 

[bluflaam777]

It still sounds like a contact issue...or lack thereof. You might have to clean the switch and any other contact on the torch. Some deoxit or equivalent might be needed.

 

[aznsx]

What does it do with a 'std' AA cell, rather than the 14500 you're using?

 

[ghostguy6]

Google tells me this light is just a rebranded Mankerlight E11 which is still available from a few places should you wish to buy a new one.

From the sounds of it you might have to take the light apart and clean the internals of the switch if possible.

 

[andygold]

What does it do with a 'std' AA cell, rather than the 14500 you're using?

Funny you should mention that! Last evening, I tried some other batteries just to make sure. All of my 14500's give me the same results (have to unscrew/screw the tail cap each time). When I switched to an AA (partially dead), the flashlight turns on and off like it should without me having to mess around with the tail cap. So, I'm thinking it might be something related to voltage. Exactly what? I have no clue!

 

[aznsx]

Funny you should mention that! Last evening, I tried some other batteries just to make sure. All of my 14500's give me the same results (have to unscrew/screw the tail cap each time). When I switched to an AA (partially dead), the flashlight turns on and off like it should without me having to mess around with the tail cap. So, I'm thinking it might be something related to voltage. Exactly what? I have no clue!

That's exactly the reply I was expecting when I asked;-) This info suggests to me that your problem is less likely to be a 'connection' failure, and is more likely to be a 'component' failure, and thus the root cause is likely to be in the electronics in the head. It could be a connection problem in the head essentially causing the appearance of a component failure, but in either case the resolution would likely involve a repair in the head.

I hate to say it, but this situation isn't sounding too promising to me at this point, but I'd like to be wrong;-) If I'm right though, resolving this might have to involve the manufacturer.

 

[andygold]

That's exactly the reply I was expecting when I asked;-) This info suggests to me that your problem is less likely to be a 'connection' failure, and is more likely to be a 'component' failure, and thus the root cause is likely to be in the electronics in the head. It could be a connection problem in the head essentially causing the appearance of a component failure, but in either case the resolution would likely involve a repair in the head.

I hate to say it, but this situation isn't sounding too promising to me at this point, but I'd like to be wrong;-) If I'm right though, resolving this might have to involve the manufacturer.

Thanks for the reply! The light is probably at least 8 years old. I'm guessing the manufacturer would laugh at me if I contacted them.

I'll have to start the search for a new 14500 light that's on the smaller size. Maybe a Wurkkos TS10 or another small light.