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Archive for February 26th, 2019

J5 Tactical Flashlight: Tailcap Switch

Mashing the LED PCB into place didn’t entirely solve the weak beam problem, so I unscrewed the tailcap holding the switch on the other end of the body:

J5 Tactical Flashlight - tailcap
J5 Tactical Flashlight – tailcap

Unscrewing the lock ring releases the switch assembly:

J5 Tactical Flashlight - tailcap parts
J5 Tactical Flashlight – tailcap parts

I suspect the tab sticking out from the side of the switch doesn’t make / never made good contact with the aluminum tailcap body, but having gone this far there’s no reason to stop. The plastic housing around the spring-loaded brass battery contact pops off to reveal the actual switch:

J5 Tactical Flashlight - switch contacts
J5 Tactical Flashlight – switch contacts

The long tab on the front of the switch sits under the spring, so that’s the negative battery contact. The LED current goes through:

  • battery negative to contact + spring
  • switch tab + moving contact + tab
  • tab to tailcap pressure fit
  • tailcap threads
  • front tube threads
  • LED pill to PCB
  • spring to battery positive

So. Many. Aluminum. Joints.

The switch body snaps apart to disgorge a remarkable number of parts:

J5 Tactical Flashlight - tailcap switch parts
J5 Tactical Flashlight – tailcap switch parts

Nothing looked out of order, so I applied a thin layer of DeoxIT Red to all the contacting parts and reassembled everything.

For the record, the switch’s internal parts have many plausible assembly sequences; the workable one goes a little something like this:

J5 Tactical Flashlight - tailcap switch contacts
J5 Tactical Flashlight – tailcap switch contacts

Contrary to what you (well, I) might think, the switch is off when the central contact is pushed forward, away from the side contacts.

I bent a slight angle into the tailcap contact (on the right in the picture) to make better / firmer contact with the tailcap body, cleaned all the threads with a cotton swab carrying a dab of DeoxIT, and screwed it all together.

With everything back together, the beam seems bright and steady again. We’ll see how long it lasts.

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