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Abnormal dot?

mfo

mfo

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About two weeks ago, I received my 125mW green laser pointer from dragon lasers. So far, I'm very impressed. However today I was messing with it, and allowed my rechargeable batteries inside of it to die. As they died, the beam and dot obviously got duller and duller until the batteries finally crapped out. When the dot was dull enough to actually look at due to the lack of power, I noticed two dots instead of one (The picture shows four). Please refer to the photo.


So, what's the deal with that? Defective or normal because of weak power? Everything else seams fine with it as far as bright dot with fresh batteries, super bright visible beam, burning, etc. Thanks for your help guys!
 

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cust11

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The two dots is known as TEM01 which is mode hopping. Your pen should stay in TEM00 unless you get it really hot. I would call DL if the pen mode hops or doesn't go back to TEM00

-Mike
 
mfo

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cust11 said:
The two dots is known as TEM01 which is mode hopping. Your pen should stay in TEM00 unless you get it really hot. I would call DL if the pen mode hops or doesn't go back to TEM00

-Mike
Click to expand...

Well, the pen isn't hot at all, so you're telling me that this is definitely abnormal for this to do that? Dead batteries definitely can't be causing this? (Note that I was using 2 AAA (1.2v NiMH x2) batteries in my pen when I took this shot.
 
cust11

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mfo said:
Well, the pen isn't hot at all, so you're telling me that this is definitely abnormal for this to do that? Dead batteries definitely can't be causing this? (Note that I was using 2 AAA (1.2v NiMH x2) batteries in my pen when I took this shot.
Click to expand...


I am not a guru about pump diodes but from what I understand a laser wont (shouldn't) mode hop unless it gets hot. I suppose it could be possible for it to mode hop under low voltage as well. I could be very wrong here and I am sure someone will chime in and correct me. I do know that mode hopping is not "abnormal" and is sometimes quite common. Not so common in an expensive pen. Regardless of the outcome I would call/email DL and tell them about your problem, possibly getting a RMA and getting it replaced.

-Mike


Edit:

Does it only mode hop when you run the batteries down really low? It is not good to run a diode driver at low voltage btw :p. I have 2 energizer e2 lithiums in my V75 that I have had for a few months and they haven't dropped below 1.49v yet O_O.
 
KGB_Productions

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Here si a pic with all the different modes....
tem_modes.png
 
cust11

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Like I said.. someone would chime in with more information :p Thanks KGB, that is really helpful. Saving it myself for later personal refrence.

-Mike
 
mfo

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Well, I just threw in some fresh Alkaline AAA batteries. Here are the results below. Also, thanks KGB, I will hold onto that image. It appears as though my laser was running in TEM11 mode. It looks like one dot to me with my digi cam, although the brightness may make it look like one. I'm going to mess with the aperture to see if I can darken it a little and reveal more.
 

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mfo

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cust11 said:
That more recent picture looks fine to me :D

-Mike
Click to expand...

Yeah, I should probably just stfu and stop worrying myself. I'll go out on a limb and say it was due to the rechargeables dying on me. Also, is it safe to use the 1.2v NiMH batteries in pointers like this? I did a fair amount of research and the conclusion I've come to is that 1.5v batteries drop down to approx. 1.2v after a few minutes of use either way, so it's all basically the same thing. Did I conclude right or wrong? Thanks a lot guys!
 
cust11

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mfo said:
Yeah, I should probably just stfu and stop worrying myself. I'll go out on a limb and say it was due to the rechargeables dying on me. Also, is it safe to use the 1.2v NiMH batteries in pointers like this? I did a fair amount of research and the conclusion I've come to is that 1.5v batteries drop down to approx. 1.2v after a few minutes of use either way, so it's all basically the same thing. Did I conclude right or wrong? Thanks a lot guys!
Click to expand...


Every driver is going to differ in min. voltage requirements. I personally run 1.7v e2 lithiums and change them when they hit 1.4v. My pen is also a DL. You may lose some burning power running 1.2v(2.3~v). I suggest you try e2 lithiums :D they cost the same as any other AAA.

As for the worrying... You have every right to worry! Your investment was not working correctly and you did not know why. As long as it doesn't mode hop under normal conditions I would say it is ok. If it starts to mode hop on you again and it is not due to heat.. pull the batteries out and test their voltage.

-Mike
 
mfo

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cust11 said:
Every driver is going to differ in min. voltage requirements. I personally run 1.7v e2 lithiums and change them when they hit 1.4v. My pen is also a DL. You may lose some burning power running 1.2v(2.3~v). I suggest you try e2 lithiums :D they cost the same as any other AAA.

As for the worrying... You have every right to worry! Your investment was not working correctly and you did not know why. As long as it doesn't mode hop under normal conditions I would say it is ok. If it starts to mode hop on you again and it is not due to heat.. pull the batteries out and test their voltage.

-Mike
Click to expand...

Thanks for your time and help Mike, I'll def. give those a try then. Btw, my name is Chris.
 
cust11

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Well in that case, pleased to meet you Chris, and welcome to the forum! You will be able to source out information for all of your questions here.

-Mike
 
GooeyGus

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There is nothing wrong with it. That is totally normal when the batteries are dying. :beer:
 
styropyro

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I had a long reply typed out but the update deleted it...

Like Gus said there is nothing wrong, very rarely will you find a pen greenie that doesn't mode hop on dead batteries. As long as it doesn't switch modes with only a decent charge your laser is running great.
 
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