My new Sunwayman F40A i got from Banggood this past month, flickers like a candle on Low.
All other modes (including the color lights) are ok. Turbo, High, Medium, and Moon light are ok, only Low flickers continuously in a random pattern. It did this from the first time i took it out of the box. I am not impressed with this flaw considering it is a $ 100 + dollar high quality light.
Anybody else seen this issue with the F40A ?
Haven't seen that issue with our floor sample, warranty it out.
I think it's called candle mode ;)
Yes, warranty. Battery and spring contacts are clean?
everything checks out good, except for thew annoying flicker on Low.
Sorry to hear that. A flashlight is a terrible thing to waste.
It's an ugly light why did you but it. Should have bought the D40A.
Hmm maybe that’s his penance for getting the F40A. The D40A is just a fantastic light. The only thing I’ve ever heard about the D40A is how awesome it is.
I have an F40A as well, works perfectly, but when I got it I didnt like it, now I love it. I dont use the colored flash but its in my truck. If I ever break down then its an awesome signal light. Put on yhe police strobe and if any cop drives by they stop automatically, just saying
I never bought it because someone else thinks its ugly. I bought it because ” I ” like it and it has feature I like.
Sorry to hear about the flicker. Hopefully you can get a replacement.
I’d like to see more lights have the colour strobe like in the F40A.
thats the main reason why i like it is bacause it has the multiple color modes.
Is the flickering a constant random flickering? Or less frequent? I ask because my Olight ST-25 flickers randomly on Ni-MH in some modes but it isn’t often enough to seem like a fault, but annoying enough because I’m fussy about such things.
its a constant flickering when its on Low. ( almost like a burning out Fluorescent tube does) all other modes are good with no flickering at all. Im thinking its a driver fault.
Out of curiosity, how difficult would it be to take a look at the driver? I’d almost be tempted to play around with the driver a bit if it’s easy to get at.
C_K driver would sort it out 
But you really should exchange the light, not acceptable for it to fail so soon.
I have not had that light but I know that flickering will drive me nuts!
I'd also get warranty claim on it asap. What a buzzkill. I've had other but related issues with high quality flashlights too. That is what got me into budget lights in the first place... On seconds thought no it was not. It was the other way around. :-D Maybe budget flashlights are like a gateway drug? LOL.
Best of luck with the coming warranty tug-o-war. Fingers crossed.
Sorry to hear. I broke my F30R driver the other day. Inserted the cells (16430) backwards and popped a FET. Datasheet search by the numbers didn’t turn up anything but thankfully there was another of the exact same so I took it off and used my transistor tester to tell me it was an N-FET so I replaced it with a AO3400 and got a single flash the first time I tried to turn it on (in white mode) and nothing else, there regulated POWER at the MCU but even shorting the SW input directly at the MCU does nothing. This was my fault but after killing my V11R (with an untouched driver) in a ~1m drop I’m no longer as confident in their circuitry.
Full disclosure this happened in my MT-G2 modded F30R but it definitely happened from the polarity incident right then, it seemed to be running fine otherwise. Thankfully I had immediate access to another F30R driver! Talk about lucky, that’ll NEVER happen again in my life.
All other modes work fine, except for Low that flickers. I did discover after i leave it on for a few minutes in medium, then switch to low it works fin then. ( but its still not perfect.