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Complete beginner looking for advice...


New Member
Hello! I feel like someone about to start trying to communicate with a very interesting group of people who speak an entirely different language, but here goes...

I know absolutely nothing about electronics. But I have always been a maker of one sort or another, and I have always preferred to mend rather than throw out. One of my (many) weaknesses is flashlights. A while back, one of my fairly high end flashlights developed a fault. It turns on, but not off. Things are complicated by the fact that it has two on/off switches, one on the tail cap and the other on the side. They work independently of one another. There is also a third switch (these are all tactile switches) which allows the user to cycle through different levels of brightness.

Apologies for the degree of detail, just context. Anyway I have dismantled the flashlight. I checked the switches for off/on continuity, both seem fine. I also noted that some of the seven leads connected onto the main circuit board appeared a bit ropey. So I jumped in, acquired a reasonable soldering station, a few basic tools and disconnected everything and replaced all the cables, most of which are ultra-fine (0.25mm). I'm happy with how that all went; my soldering even looks slightly better than the original. But the fault remains. Both main switches turn on the flashlight and the cycling function works perfectly. But the only way to turn the flashlight off is by loosening the end cap to break the circuit (and no, tightening it back up doesn't reactivate the flashlight). The actual switch connectivity through the body of the flashlight seems fine, so I am left assuming that one of the components on the circuit board is faulty.

I don't know where to go next. I can't find anything online about the circuit board (not that I'd necessarily understand it if I did) and although I might be able to source replacement components to swap out, I would be shooting in the dark.

Can anyone point me in the direction of newbe-friendly information source, or perhaps even suggest what my next move might be please (aside from buy new flashlight).

Thanks. If I don't get anywhere I do at least think this may be the start of something bigger so onwards and upwards.


Active Member
Sorry, but you are shooting in the dark.
We need some lead to start thinking.

For a start, give the Name and Model of the flashlight.


New Member
I guessed I probably was... The flashlight is an Eagtac MX30L3. I've attached a couple of photographs of the circuit board. 20210604_140445.jpg20210604_140944.jpg


Well-Known Member
If you are feeling brave, you should try re-working all the soldered joints on the PCB. Just melt each one quickly with the soldering iron. Ideally you'd put a bit of flux on first but it's not strictly necessary. You might need a spot of fresh solder here and there though. Be careful not to create solder bridges!
Hopefully it will just be a dry joint that's causing the problem, and re-work will fix it.

An issue I've had with one of these type of torches was bad contact between the board and the casing, so it's a worthwhile test to connect the battery with wires and check if it still fails this way.

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