My FW3A won’t turn on after I let someone use it and trying to unscrew the tailcap.
Battery is fully charged retaining ring seem tight enough.
Clicking or holding down the tail e-switch does not turn it on.
Have you tried removing the head and loosening then retightening the tailcap, reinsert the cell (it is charged?) And then replace and tighten the head?
Did they just loosen the tailcap a little or actually remove it? If it is a version without the newer tailcap that has the retaining ring they may have lost the little “nub”
Thanks MtnDon
My version is from Mid 2019.
I am not sure what exactly happened to the tailcap but I assume it could have been removed.
Yes I removed the head, tightened tailcap and Yes Battery is charged
You could try loosening the retaining ring in the tailcap slightly. That helped with a poor contact on an FW3 for a period.
I loosened it a bit, sofar no joy, it is not turning on, and also no “blink” - battery check on contact. but I appreciate your suggestion,
You don’t get the power connected blink? That is a basic function not connected to the switch or inner tube. It’s just battery power going through the tail cap and battery tube to the head. This explains the switch not working. The driver is not getting power.
You will need to start with the basics. Take just the head and attach a battery to it. Then use a wire to go from the battery negative to the exposed threads on the head. Stick the wire end next to the battery to reach the threads.
If too hard, install the battery tube minus the inner tube (we will assume good contact from the head to battery tube) then run your wire from battery negative to the exposed threads on the battery tube.
You should see the power connected blink. If not, there is a problem in the head. Try loosening and then tightening the driver retaining ring. Make sure it’s sitting flat and is centered. Test again to see if it gets power.
If not, remove the TIR lens and make sure the wires to the leds are still attached. If so, the problem might be in the driver which is a bit more complicated to diagnose and requires soldering equipment.
Also, try wiping the threads clean, using a little bit of conductive lubricant (“bulb grease”)
A bit of grit can cause a lot of misbehavior.
Just a quick warning: “Bulb grease” is not conductive. It is an insulator used to protect electrical contacts from water/corrosion and arcing. The electric connection is made by the contact points between the two objects.
Sadly this misinformation (that bulb grease is conductive and that conductive substances should be used in flashlights) is shared by hank repeatedly in this forum.
Using any kind of conductive substance in your flashlight will cause shorts and other issues at some point.
good to know, thank you for the heads up. I always use bulb grease when changing my car’s headlights. Always assumed it was to keep rain water out, not help with conductivity.
Correct, that’s the main purpose for it. But in some way it also helps with conductivity because it seals all metal surfaces from moisture and air. This prevents corrosion which would cause contact issues.
Depending on the ingredients, bulb grease might be suitable for flashlights. If you want to be on the safe side, use silicone based grease (the cheap stuff works, but you can also buy the expensive Nyogel that has slightly better lubrication and stability properties).
PS: Edited my previous post to make clear which misinformation I meant.
Just for the record, I thought we’d agreed to disagree about the existence of conductive grease,.
But since you repost the same claim, I’ll repost the response. Google finds a variety of products.
Nyogel is the one that has been recommended for flashlight users for years now. Not all of their products, only the conductive type.
and
Of course you don’t want to gorp it on and cause a short circuit, as cautioned above.
Rather, you wipe the threads to clean them (aluminum oxidizes to make that black insulating dirt you see in the threads after a while, that’s what you’re cleaning up)
Let’s not keep repeating this, huh?
“It doesn’t exist and you shouldn’t use it”
“It exists and here’s the reference”
repeating this exchange back and forth isn’t helpful. I”ll just link back to this next go-round rather than retype the references again.
I don’t think we have agreed, at least I didn’t. I accept that you insist on your standpoint, but I see it as necessary to correct your dangerous advice when I see it.
I’ve never seen Nyogel 756G or 758G recommended for flashlights. The usual recommendation is 760G:
I’ve never denied the existence of conductive grease. But it is not relevant for our use cases. And this repetition is helpful because it might protect other people from ruining their flashlights.
I do have a question about the property of grease used in the threads. As I understand it, anodized aluminum is non-conductive. Electrical current and e-switch signals should be happening within the body via the tube, right? If so, why would I need a conductive grease on the anodized threads of its not meant to conduct any current? Wouldn’t plain lubrication and chemical stability be the priority?
I think the switch relies on the inner tube for its signals but the outer tube still is used to carry current for the driver.
Don’t use conductive lubricant in a flashlight. It’s a quick way to get shorts and leaks which are very difficult to get rid of, and can cause the light to stop functioning correctly.
The type of lubricant needed is dielectric / non-conductive.
It can also be important to make sure the lubricant does not cause the O-rings to dissolve. I forget which types do that, but two safe common types are Nyogel 760G and Super Lube PTFE. Both are dielectric and safe for O-rings. The latter is even food-grade; it’s basically Teflon gel.
Thank you all for trying to help
I connected the head to the battery, the way you described it, I got some sparks initially, smelled some smoke but nothing else. Light is not turning on and no blinks.Then I put on the outer tube, and nothing at all.
retaining rings seem to be tight enough, I didn’t take apart the head yet, I think I need a little different pliers. Dont want to damage the threads
Applying power to the head might cause a super tiny spark if your looking real close, but definitely not a big spark or cause smoke visually or by smell. It sounds like you have a bad driver.
One possible scenario is the person you lent it to might have put the battery in backwards and it damaged the driver. Maybe? IDK. I believe I’ve seen replacement drivers being sold. You’d need to be able to solder the 2 wires going to the LED’s, to swap it. Not too complicated.
One thing to try and loosen the driver retaining ring is to push on one notch with a tool like a tiny flat head screwdriver. Alternate sides. Most snap ring pliers are too big to reach in and grab it.
I see so FW3A doesn’t have reverse polarity protection. Will keep trying to take apart the head. and get a driver if nothing else.
Thank you again
I don’t know. I see one diode on the MCU power input. I guess that protects the MCU.
I tried digging around and can not find out for sure if has reverse polarity protection. Maybe someone who knows will comment. I am just trying to think of what could possibly happen that might cause the driver to stop working. They are pretty robust.
Another possible scenario might be the other person left it on turbo for too long and damaged one of the LEDs. A shorted led might try to pass current causing a spark when power is connected and a burning smell. Actually, anything that is shorted will do that. Ceramic capacitors used for filtering AC current do occasionally short. That is seen in Apple laptops all the time. In this FW3A driver I see at least three filtering caps. The FET or a 7135 chip could have also shorted, but that’s rare.
You should be able to check whether or not the LEDs are working by installing a battery in the light, removing the lens and using a jumper wire from the black negative connector on the mcpcb directly to a ground point in the head. When a battery is installed you have power going to the LED red wire all the time and the driver basically controls the current going to ground. So if you short it, you will get Turbo power to the leds. You just want to touch the wire super fast to see if the leds light up or not. You don’t want them to overheat.
Here is a basic diagram of a FET driver flashlight. You see how the black wire goes from the mcpcb to the driver? If you short that negative to ground you basically bypass the driver and the LEDs should come on full power. If you short the wire and the LEDs don’t come on, make sure you’re getting voltage on the red wire. If you put 3 to 4 volts across those LED wires it should work unless there is a problem with a burnt-out LED or a shorted out LED.
OK, I’ll defer to TK’s advice hereafter. It’s the conservative approach, no question about that.
I suppose an overheated lamp could vaporize the gel and redeposit it in bad places, on a high powered light.
Tho’ from experience, I’ve got a handful of Arc AAAs on which I’ve long ago cleaned up contact surfaces with [a tiny dab of] Nyogel and cured flickering due to dirty threads.
Note the black powder that accumulates on aluminum threads — it’s aluminum oxide, an insulator, that forms and is scraped off any time the threads are worked.
That’s what you want to remove. Wipe with a clean cloth if you don’t have the recommended lubricant to pick the stuff up.
Aluminum itelf reacts extremely fast with oxygen in the air, so produces a fresh oxide layer immediately when the thread contact moves.