Hi,
I have a Cyansky P25 V1 that has problems. It is limited to a very low level where only 2 of the 4 dies lights up. One of the ones that actually light up is brighter than the other. Interestingly it will go into strobe, but again at very low level. No other modes are available when it is in this state.
But, occasionally (not often) it will work properly. I have done all of the things that I normally do when I have problems with a light. New cells, tightening the tail cap switch retaining ring, and cleaning all of the contact areas.
I id manage to pull the head off (it was glued). I checked and reflowed the solder connections to the star. It actually worked right for a bit. But when running it through the modes when it got to the high setting, it immediately dimmed to the failure levels.
So the question is, does anyone have any thoughts about what the problem could be?
Is it worth trying to reflow the LED, or replace it (maybe with a 70.3?). Or does it sound like a driver issue. If it is the driver, I am not sure I can replace it as it is probably either proprietary or just too much of a PIA for me to do (side electronic switch).
Cyansky did replace the light, but if I can fix it and maybe learn something in the process, so much the better.
I would go in order. If soldering the contacts helped, try soldering the diode. Simply remove the star and place it on the iron until the tin under the diode melts.
THX. I am not sure if touching up the power leads helped or if it was just randomly working as it has in the past. But I do think that the next easiest thing would be to reheat the LED.
Better to remove it and add some reflow flux? Or maybe add some solder paste and redo it completely. ( I just bought some). Or maybe just reheat? I am all about easy. This will be my first attempt at flowing an LED onto a board.
My guess is that it’s probably the driver. It seems LEDs are pretty darn tough and if they go bad you should be able to see some damage and/or they emit a purple color.
You could test the LED with another driver if you have one, or just put 4 AAs in series (around 2 amps) and see if it lights up. If it does, then you have a different problem. And if it doesn’t, then I can see it being worthwhile reflowing or replacing it.
To reflow, I would heat it up and remove the LED. Then clean up the MCPCB, put down some solder paste, and reflow it.
I was thinking driver myself. But could not think of something that would be intermittent like this is.
I may as well pull the MCPCB out to take a look. Maybe I can figure out a way to rig the 4 AAs to test.
What is curious about a driver problem is why only half the LED lights up. I thought with the 6 volt version they ran 2 series pairs in parallel.
But I am not sure.
Do try to reflow the emitter. Sometimes one of the contacts can be covered in a thin layer of flux which causes a bad connection, and redoing the reflow fixed my 3V xhp50.2 exhibiting a similar problem.
Thanks. I will give it a go. Ordered a cheap hot plate.
I would welcome some replies from some of the driver gurus out there as to whether a bad driver could cause this. OTH, I guess I should know after relowing the LED… unless the emitter just has a problem.
Well, surprisingly, I think the LED is the problem… unless the MCPCB is hosed somehow. I reflowed the 70.2. Pretty sure that worked fine. I used 4 AAs to test it. (Thanks for the idea @NeutralFan !!) Well, only half of it lit up. Anyway, I think I will buy a 70.3 HI on a 20 mm MCPCB and install it. I hope it it worth it… as I really don’t need the light.
OTH, I finally got off my but and reflowed an LED.
I did get a replacement flashlight. They actually sent me a P25 V2 for my V1. CYANSKI CS was great about it.
But I just want to fix the one that is not working. I have changed led/MCPCBs and drivers. But had not swapped or reflowed LEDs. So this is my chance to get into that a bit.
I ordered a 5K XHP 70.3 HD on MCPCB from Convoy. So I will put that in and see how it goes (whenever I get it…). Hopefully the driver is not dead as well.
Worst case I will just keep it for parts.
It appears the LED is the issue and hopefully the new one will work. Totally worth the cost (to me) since I would have hard time not trying to revive it.
