Dead Surefire U2 - please help

Flyhigh · Jun 11, 2006

My new U2 had a problem right out of the box with the tail cap; it couldn't be switched on constantly. SF has kindly offered to help me by sending a new tail cap. However, until a few hours ago, it was at least possible to turn the light on by pushing and holding the clicker but now it's completely dead. It died on me when I adjusted the light to the highest setting. As far as I can tell the tail cap looks the same it always did, no bent pins or anything (I haven't disassembled it though, I'm too afraid to break it or not be able to put it back together again).

Will the new tail cap fix this or do I need to send my U2 back to SF to have it repaired or, preferably, is there something I can do myself? Please advice, I already have to wait to get the new tail cap sent to Sweden, having to wait additional months for a fully functional light is not something I look forward to.

Warp · Jun 11, 2006

Can you try taking the tailcap off and using piece of metal to bridge the gap between the inside of the body and the end of the battery.

That is how I tested my G2 when my tailcap went bad (due to being dunked while on). I am unfamilier iwth the U2 but it may be worth a shot

Flash_Gordon · Jun 11, 2006

You can easily confirm if the tailcap is the only source of your problem. It probably is.

Remove the tailcap completely. Use a paper clip or key or piece of wire. Short the negative battery terminal to the inside of the tube or to the threads.

If your light works normally, the tailcap is the problem. Make sure that you are using a known fresh, good pair of batteries.

You can try to stretch the tailcap spring very slightly. This may help with proper contact.

If you search this forum there have been several threads on repairing SF tailcaps. Proceed if you feel comfortable doing so.

Mark

carrot · Jun 11, 2006

Have you tried new batteries in it or setting the power selector to the lowest output level? This may solve the "no light" problem if it's not the tailcap. Also, try removing the tailcap and using a short wire or something to connect the negative end of the battery to the rear of the light, just to ensure that it's not a switch problem. Total U2 failure is pretty rare from what I've seen on CPF.

With the clickies on U2's and E-series Surefires it seems "sticking" is a problem with the switch assembly on the inside. After you get Surefire to promise you a new tailcap you might as well try disassembling the "broken" tailcap to unstick it. Cleaning off the stock lube and replacing it with a dab of something thinner fixed my z57 tailcap problems completely. There are a number of tutorials on this... lots of useful info in this thread, for example: http://candlepowerforums.com/vb/showthread.php?t=113000

The same information that applies to the z57 E-series/L4 tailcap pretty much applies to the U2 tailcap as well.

Flyhigh · Jun 11, 2006

Warp said:
Can you try taking the tailcap off and using piece of metal to bridge the gap between the inside of the body and the end of the battery.

Thanks for the tip Warp, greatly appreciated, but I'm afraid it didn't work. I'm really scratching my head here; I have no clue on what's wrong with my U2. Could it be the microprocessor?

jar3ds · Jun 11, 2006

you have good batteries... and your sure you bridge the gap correctly with the wire?

Flyhigh · Jun 11, 2006

carrot said:
Have you tried new batteries in it or setting the power selector to the lowest output level? This may solve the "no light" problem if it's not the tailcap. Also, try removing the tailcap and using a short wire or something to connect the negative end of the battery to the rear of the light, just to ensure that it's not a switch problem. Total U2 failure is pretty rare from what I've seen on CPF.QUOTE]

Thanks for your input flash-gordon and carrot. I've tried all of the above and still no light. No total U2 failure, huh? There has to be a first for everything, I'm just not very happy to be the one!

Flyhigh · Jun 11, 2006

I think I'm doing it correctly, is there a special way? I have tried new batteries as well and the tail cap is not stuck.

Thanks for your input

greenLED · Jun 11, 2006

Your problems sounds exactly like what I had with my first U2. Take the tailcap off the light and look inside it. There are 3-4 little metal tabs around the spring; they are on a metal ring. Use a toothpick (or another object) and bend those upwards a bit. Replace tailcap (tighten) on light and... voilà. You can thank me later.

...if that works of course... :nana:

Incidentally, this thread is the encyclopedia of how to fix U2 problems.

Flyhigh · Jun 12, 2006

Thanks greenLED, I tried it but it did not work I'm afraid.

Looks like I'll have to return my U2. Its a shame becuase when it worked (one day) it was bright with no doughnut hole.

TENMMIKE · Jun 12, 2006

lets be clear have you put a wire to the neg(-)part of battery and the threaded part of the body(with the tail cap off!)? say yes or no , are you positive by multimeter your batteries are good? yes or no , if yes on both you need to send back , the U-2 has problems but this is one that is not the most common of the problems, but as greenled said it has happened (and to him).

Flyhigh · Jun 12, 2006

Thanks TENMIKE, I've tried the way you described, still no light. I've mailed SF for advice and am waiting for an answer but it looks increasingly likely that I have to return my U2. Hopefully They'll repair it rather than making an exchange.

glockboy · Jun 12, 2006

Try open the body of the light and see the head if the positive sping contact with the battery positive nipple, if not get the needle nose pliers and pull the sping out a little bit so it contact with the battery positive nipple.

Flyhigh · Jun 12, 2006

glockboy said:
Try open the body of the light and see the head if the positive sping contact with the battery positive nipple, if not get the needle nose pliers and pull the sping out a little bit so it contact with the battery positive nipple.

Thanks for the tip glockboy, I've done that and it still doesn't work. I'm beginning to think that it is a faulty microprocessor, I don't see what else it could be.

Tremendo · Jun 12, 2006

If you had a good tint and no donut, make sure you've tried all easy fix options before you send it back. You may get a working light back, but you will likely get some type of donut. My U2 has a good tint and a medium to big donut, but it is still such a useful light I'm keeping it.

grnamin · Jun 12, 2006

I belong to the "Don't Send It Back To Surefire, Fix It Yourself" camp. The LED in the U2 can be replaced with a guaranteed whiter bin and the reflector position can be shimmed to minimize or eliminate the donut, all these IF you can open up the bezel. I've had the chance to try to open up 4 U2s in order to replace the LED and shim the reflector and, so far, I haven't been able to open 1 of them. Surefire must have arc-welded that one shut.

The tailcap switch is fixable as well. I waited 4 months for Surefire to send me a tailcap when 3rd U2's switch wouldn't work. When the tailcap finally arrived, it was in HA III natural, not black. In the time it took SF to send me a replacement, I had learned, through the members here, how to fix the switch myself.

cheapo · Jun 12, 2006

there is no u2 ha3 natural is there? also, at which levels are the donuts visible??

-david

JasonC8301 · Jun 12, 2006

cheapo - probably a mix up at SF's end, the Z58 is the HA nat clicky tailcap and the Z59 is the HA black tailcap.

cheapo · Jun 12, 2006

i can neither confirm, nor deny that i just ordered a u2

... hopefully i get one without a donut, but based on what i have heard, the chances are slim. Well, i am ordering the newest version, and i hope those have better LEDS than the older version.

-David

Flyhigh · Jun 12, 2006

grnamin said:
I belong to the "Don't Send It Back To Surefire, Fix It Yourself" camp. The LED in the U2 can be replaced with a guaranteed whiter bin and the reflector position can be shimmed to minimize or eliminate the donut, all these IF you can open up the bezel. I've had the chance to try to open up 4 U2s in order to replace the LED and shim the reflector and, so far, I haven't been able to open 1 of them. Surefire must have arc-welded that one shut.

The tailcap switch is fixable as well. I waited 4 months for Surefire to send me a tailcap when 3rd U2's switch wouldn't work. When the tailcap finally arrived, it was in HA III natural, not black. In the time it took SF to send me a replacement, I had learned, through the members here, how to fix the switch myself.

I agree on principle but being a guy with five thumbs on each hand I have to be careful. Tremendo: And yes, it was a very good light when it worked (sigh).

Cheapo: hope you luck out, it is a really nice light but with some QC issues. Btw, The serialno on mine is A10449, so its fairly new.

Dead Surefire U2 - please help

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