FW3A Troubleshooting / FAQ

[JasonWW]

@pennzy

So the spring is carrying high current and should never touch the signal trace which only carries low current.?

Not really.

The spring should only carry high current when the light is on a very high brightness level.

The trace only carries low current.

From what I can figure out, if the spring touches the trace it simply bypasses the switch so the light turns on. There should be no high current flowing through there.

There should be no way you’d have high current due to a short. The battery positive goes straight from the battery end to the leds and stops at the driver FET and 7135 current regulators. So there is no positive battery power in the tail except for the tiny trace signal coming from the MCU. This current is regulated at a very low level though since pushing the button shorts it to ground and no high current flows then.

When the light turns on Turbo you get a lot of current (12A) go through the spring to the 3 solder pads. Then it goes through vias to the backside of the pcb. That whole backside is negative except for the small circle pad under the metal switch dome.

So if the spring touches the trace, high current will flow through the vias like normal, but I don’t see how high current would want to flow through the trace. That trace doesn’t go anywhere but through the inner tube to the MCU pin.

Maybe the spring got hot from only being soldered in one spot instead of 3 and the heat transfered to the trace? IDK, I’m stuck on how it could happen.

[JasonWW]

Maybe the current flowed through both the vias and the skinny trace and the vias can handle much heavier loads so the trace heated up?

[goshdogit]

@goshdogit

I assume (perhaps incorrectly) that springs tend to be installed so that the ‘end’ is on a pad and connected with solder.

@shirnask

… the end of my spring sits directly on top of the trace that shorted …

I stand corrected. Yikes!

[JasonWW]

@shirnask

You guys had me worried a bit with this discussion because the end of my spring sits directly on top of the trace that shorted and I have knocked the light off a 2 drawer file cabinet where it lives no less than a dozen times (likely an underestimate) . Yes I am that clumsy.

Yes there is only one good solder pad holding the spring. But fortunately it is the one to the left of the trace which happens to be holding the end of the spring slightly above the surface and I expect that makes all the difference

Push the spring down hard, see if it flexes at all.

[teacher]

/\ … If it does, slide a small piece of plastic milk carton under it & forget it.

[DBSAR]

@JasonWW

Maybe the current flowed through both the vias and the skinny trace and the vias can handle much heavier loads so the trace heated up?

I have no idea, but i tried to power up the head after after using some jumper leads and a 18650 battery holder with wires and could not get it to turn on. (positive wire to the driver spring, negative to the threads in the head, and used a third jumper to act as an electronic switch to the inner tube ring on the driver.

[shirnask]

@JasonWW

@shirnask

…

Push the spring down hard, see if it flexes at all.

The only way the end of the spring is going to hit the trace is if the impact is hard enough to break the good solder joint to the left of the trace. I’m looking for something thin enough to get under the end of the spring.

[JasonWW]

@DBSAR

@JasonWW

Maybe the current flowed through both the vias and the skinny trace and the vias can handle much heavier loads so the trace heated up?

I have no idea, but i tried to power up the head after after using some jumper leads and a 18650 battery holder with wires and could not get it to turn on. (positive wire to the driver spring, negative to the threads in the head, and used a third jumper to act as an electronic switch to the inner tube ring on the driver.

Don’t feel bad, I can’t get mine to turn on like that either. I tried bypassing the tail switch, though.

[DBSAR]

@JasonWW

ative to the threads in the head, and used a third jumper to act as an electronic switch to the inner tube ring on the driver.

Don’t feel bad, I can’t get mine to turn on like that either. I tried bypassing the tail switch, though.
[/quote]

You had one fail too?

[JasonWW]

@DBSAR

@JasonWW

@DBSAR

I have no idea, but i tried to power up the head after after using some jumper leads and a 18650 battery holder with wires and could not get it to turn on. (positive wire to the driver spring, negative to the threads in the head, and used a third jumper to act as an electronic switch to the inner tube ring on the driver.

Don’t feel bad, I can’t get mine to turn on like that either. I tried bypassing the tail switch, though.

You had one fail too?

No, I was trying to measure the amp draw.

[DBSAR]

@JasonWW

No, I was trying to measure the amp draw.

ah ok. I have not been brave enough yet to have tried to figure out to do amp load test on this light. ( i just tried to get the head to work to see if the main driver was still working or not. As Dr. Mcoy once said: ” It’s dead Jim”

[WalkIntoTheLight]

Are you saying the sharp end of the spring was directly over that trace? I assume it was a flat coil.

I examined mine, and yup, the sharp end of the spring was right over the trace. Practically touching. :rage:

The solder job on mine was really bad, too. Just one contact point, and the spring was way off center.

I desoldered it, and did an equally sh*tty solder job putting it back together. But, at least it’s centered, the sharp end is 180 degrees away from the trace, and there’s two contact points (couldn’t get the third for some reason). I also added some more solder so the spring sits up higher. There’s a good millimeter of space between the spring and the board.

I hope I did that correctly. Anyway, the light works fine, and the spring seems solidly in place.

Thanks to DBSAR and this thread for pointing out this potentially dangerous flaw.

[xevious (Gary)]

@teacher

/\ … If it does, slide a small piece of plastic milk carton under it & forget it.

That sounds like a good idea. Might be worthwhile to put a spot of flexible glue there to help hold it in place.

This is a tragic oversight on the part of Lumintop. I can’t imagine how many FW3A’s will have the faulty spring orientation and will very likely suffer functional fault from a routine drop of the light.

Mine isn’t in danger, because the spring is off center (poor soldering job). It’s still good enough to make contact, though. Here’s a photo (sorry for the crappy quality — couldn’t get my phone to focus properly):

[teacher]

@WalkIntoTheLight

Thanks to DBSAR and this thread for pointing out this potentially dangerous flaw.

Amen…… appreciate you ’taking one for the team’ DBSAR!!

Even though you didn’t volunteer & it was forced upon you by circumstance…. you once again for a second time :person_facepalming: …… handled it like a champ!!!

[DBSAR]

@teacher

@WalkIntoTheLight

Thanks to DBSAR and this thread for pointing out this potentially dangerous flaw.

Amen…… appreciate you ’taking one for the team’ DBSAR!!

Even though you didn’t volunteer & it was forced upon you by circumstance…. you once again for a second time :person_facepalming: …… handled it like a champ!!!

no doubt, from what i can gather from this, is that if the spring shorts to the trace from an impact of abrasion over time if the spring cut edge is pressing on that trace, the light will turn on from that short and begin ramping up to its maximum mode and can not be turned off until the battery is removed. (could result in a fire if it was in a backpack and it happened, because this little light really throws out some heat on high.

[CLB]

@DBSAR

while the edge of the spring was not directly on the trace, as seen in the photo the spring edge was roughly 110 degrees at roughly 2 o’clock on the board, so the spring was directly resting on the trace.

I understand the reasoning that if the sharp end of the spring is directly over the trace, a sharp impact could cause the spring end to puncture the mask over the trace and cause a short. But if I am reading DBSAR correctly, the end of the spring on his light was NOT over the trace, but was at 2 o’clock. So, it was the smooth section, not the end, of the spring that was over the trace. Is it plausible in that circimstamce for the spring to have punctured the mask in a one foot fall?

If it is, then virtually all the FW3A’s would be at risk (unless the end of the spring happened to be soldered to the pad at 8 o’clock, which is something no one has yet reported seeing). Both my lights have the spring end over the 4 o’clock pad, with the spring touching the mask over the trace, and no room for sliding in a plastic insulator.

Am I understanding this issue correctly?

[teacher]

My spring end looks OK also. It is centered & two solder pads seem to be holding it firmly. With the “FW3A” at 6 o’clock the spring end is at about 3 o’clock, almost touching the ’little grommet hole thing’ (at 3 o'clock) .

[pennzy]

Might be more the way it was only soldered on one spot.

[teacher]

@CLB

@DBSAR

while the edge of the spring was not directly on the trace, as seen in the photo the spring edge was roughly 110 degrees at roughly 2 o’clock on the board, so the spring was directly resting on the trace.

I understand the reasoning that if the sharp end of the spring is directly over the trace, a sharp impact could cause the spring end to puncture the mask over the trace and cause a short. But if I am reading DBSAR correctly, the end of the spring on his light was NOT over the trace, but was at 2 o’clock. So, it was the smooth section, not the end, of the spring that was over the trace. Is it plausible in that circimstamce for the spring to have punctured the mask in a one foot fall?

If it is, then virtually all the FW3A’s would be at risk (unless the end of the spring happened to be soldered to the pad at 8 o’clock, which is something no one has yet reported seeing). Both my lights have the spring end over the 4 o’clock pad, with the spring touching the mask over the trace, and no room for sliding in a plastic insulator.

Am I understanding this issue correctly?

Hmmmmm…. good point CLB. … :+1:

[DBSAR]

@teacher

@CLB

@DBSAR

while the edge of the spring was not directly on the trace, as seen in the photo the spring edge was roughly 110 degrees at roughly 2 o’clock on the board, so the spring was directly resting on the trace.

I understand the reasoning that if the sharp end of the spring is directly over the trace, a sharp impact could cause the spring end to puncture the mask over the trace and cause a short. But if I am reading DBSAR correctly, the end of the spring on his light was NOT over the trace, but was at 2 o’clock. So, it was the smooth section, not the end, of the spring that was over the trace. Is it plausible in that circimstamce for the spring to have punctured the mask in a one foot fall?

If it is, then virtually all the FW3A’s would be at risk (unless the end of the spring happened to be soldered to the pad at 8 o’clock, which is something no one has yet reported seeing). Both my lights have the spring end over the 4 o’clock pad, with the spring touching the mask over the trace, and no room for sliding in a plastic insulator.

Am I understanding this issue correctly?

Hmmmmm…. good point CLB. … :+1:

it seems some have reported their springs to be in random positions, some with only one of the three pads soldered, some have two, and indeed mine had the spring edge roughly at the 3 o’clock position, but the spring surface was still against the trace mask, but only had the 8 o’clock pad soldered. it was a bunch of unlucky circumstances to what happened to mine, if toppled over off a 20” high night table, landed tail down hard on a hard-wood floor with a sharp “clunk” then it instantly turned on and began to ramp up to maximum mode on its own. I guess the weight of the 30Q had slammed down hard enough on the spring to force it through the mask to the trace. After that i don’t know what happened as i kept trying to turn it off with the switch to no avail. then tapped it a couple times on the edge of the table, then it went out but still flickered, it was really hot after running on max for the minute or so, i then began to unscrew the extremely hot head section to pull the battery out. I have no idea if something else also shorted in the head, but something obviously sent a ton of amps current through that shorted trace to burn & melt it like a fuse.