Challenge of Repairing vs Trashing

Therese things are so simple, it's almost embarrassing to ask how to fix them. Temperature isn't the cause of the problem. Most likely the on-off switch has pitted contacts. Disassemble the switch and burnish of file the contacts until the pitting is gone. Another possibility is that the switch contacts have lost "springiness" and are barely making contact. Dissasemble the switch and bend them until there is sufficient force to make firm contact. If there is no switch (the head and the tube are screwed together to turn the flashlight on), disassemble the flashlight and clean the dirt or other stuff that's keeping the pieces from making good contact. Last, see if the button of solder in the head that contacts the battery, has taken a depression so that it's not making contact with the battery. If so, put another good blob of solder on it to make vetter contact.

--
David
dgminala at mediacombb dot net

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Not so sure about that. I have noticed that my cheap 3 LED flashlight puts out a moderate RFI when on. Presumably there is a switcher of some sort that ups the 1.4V from a single AA cell to run the 3 LEDs. If the OP's one has asimilar switcher, it could have failed in the cold [poor Pb free solder joint?] and remained faulty when warmed back up again.

Neil S.

That would be my thoughts, too. These flashlights are often not quite as simple as the other poster seems to believe, and it's common to have an inverter chip built in which, in conjunction with a small external choke, produces the required voltage at a constant current, to run the LED(s) until the battery or single cell has reached way below where it would normally power anything, let alone one or more white LEDs. There are many examples of how this all works on the 'net. A couple of years ago, Elektor magazine gave away a little board with one of these ICs and a choke on it, free on the front of every copy, for readers to play with. I still have mine connected to a white LED set in the end of an old ball pen tube to use as a light 'probe' when looking for problems deep in CD or tape mechanisms where the normal bench light won't reach. It runs from a single NiCd cell and remains at full brightness until the cell just falls over and dies.

Just an additional thought. The problem could also be the LED itself. I have seen them go intermittent, and if this one is being pulse driven from an IC, then it might well be that a faulty LED would flicker as the chip tries to keep it supplied with a constant pulse current.

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I like the inadvertent buit-in charge meter of multi-LED torch lamps where they are all in parallel (plus a bit of pcb trace drop). You can tell the state of battery charge as one or more fail to illuminate, more "failing" with less charge/voltage .

There are only a few components on the inverter-type board for the Nite-Ize upgrade kits, which extend the battery life of 2 alkaline AA cells to about

20 hours, driving 3 high brightness (not high power) white LEDs. The circuit board is only about 15mm in diameter, smaller than a dime/US 10 cent piece, populated with components on both sides.

I've found these to be very reliable and worthwhile, although they don't "throw" much light.. which is common with many LED devices without exceptionally good reflectors and/or lenses.

-- Cheers, WB .............

I'd like to know of a source for those little green/yellow/red LED charge indicators or another compact product that would work well with rechargeable battery packs of 6 to 12V with a push-to-test button.

-- Cheers, WB .............

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Interesting. This torch is a 'fat' mag-like lite and has six LED's with the small 'dime' size PCB and a 3 battery pack plastic assembly.

Closer examination shows that 3 LED's stay lit, but the others are OFF, except one or two [of the three on one side] flicker as though trying to come ON. Flicker rate is more like ON for 20 OFF for 80. Eye retention gives the impression that the LED(s) is on longer.

Earlier comments about connection are interesting in that unscrewing the front end with the LED assembly - the LED's pretty much stay lit. BUT! even the slightest unscrewing the tail end [where switch is located] causes LED's to either go out or substantially change flicker patterns.

Regards,

There are some very poorly made LED flashlights around, and some of them are anything but reliable.

I generally take most things apart to see the (lack of) quality of work/production methods. One package of extremely low cost 3-AAA cell F-Ls were made to very low quality standards.. the LED leads were just twisted together to form the (+) battery contact, and the (-) leads-to-case were just jammed between the plastic "reflector" and case. Apparently, these were all hand assembled, and had no soldered connections in them.

In general, the heavier the case and the more machining that's required to make the case parts, the better the quality of production, as far as I've seen.

Some of the better quality 1W single LED models ($4-8) that I use regularly have been very reliable.

While I have them apart, I'll apply a little DeoxIT paste to contacts, seals and threads.

-- Cheers, WB .............

Interesting. This torch is a 'fat' mag-like lite and has six LED's with the small 'dime' size PCB and a 3 battery pack plastic assembly.

Closer examination shows that 3 LED's stay lit, but the others are OFF, except one or two [of the three on one side] flicker as though trying to come ON. Flicker rate is more like ON for 20 OFF for 80. Eye retention gives the impression that the LED(s) is on longer.

Earlier comments about connection are interesting in that unscrewing the front end with the LED assembly - the LED's pretty much stay lit. BUT! even the slightest unscrewing the tail end [where switch is located] causes LED's to either go out or substantially change flicker patterns.

Regards,

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Is this a Harbor Freight lite, of one very similar? The switch is a rubber button in the screw-on base, and is marginally usable for 500 pushes.

You can find several different types of replacment pushbutton switches and the flexible covers for LED flashlights on

--
You can't fix stupid. You can't even put a Band-Aid? on it, because it's
Teflon coated.

The specific cheapest models I mentioned are 9-LED, with 3-AAA cell holders, which came from an eBag seller.. but generally the quality of much of Harbor-F merchandise.

The switch is in the end cap.. and another characteristic of low quality units, is the shiney plastic flexible vinyl covers on the switches, not the softer, flat black more rubbery-like stuff.

The case is 7/8 to 15/16" in diameter, and 3-1/4" length overall.. very thin tubing without many deep features.

The value may be to salvage the LEDs (since the leads are long and not soldered) and the battery holder for use in other, better lights. These cheap units aren't even good gifts, IMO.. probably better as give-away trinkets but not to friends.

-- Cheers, WB .............

Is this a Harbor Freight lite, of one very similar? The switch is a rubber button in the screw-on base, and is marginally usable for 500 pushes.