Circuit damage in a Malkoff?

[tomcat017]

Hi everyone,

I have a quick question about a malfunctional malkoff M60 (I hope this is the apporpriate subforum--I believe it's an electrical problem). I put a light together for a friend using a malkoff M60 in a SF 9P. It's running on 2 17500's. Yesterday, my friend called and said the light stopped working after he changed the batteries. The other set wouldn't work either. My first thought was that he installed the bats backwards, and the circuit didn't like it. He sats that they are in correctly now, and it won't light, but that he thinks he had them in wrong for a second. Would this explain the failure, or is the Malkoff polarity protected? Is there any way that I can test the drop-in to confirm it? And if it is the reason, is it shot for good? He's going to bring the light by tonight, and I'll take a look. Thanks for any help!! Poor drop-in :-(.

 

[Bullzeyebill]

Scary. The one reason I do not let people use any of my Led lights that are not polarity protected. In your case the Malkoff apparently belongs to your friend. No, the Malkoff is not polarity protected and most modded Led lights and Led drop ins are not polarity protected. I suspect that the Surefire drop ins are polarity protected as they sell lights to non flashaholics, who will, accidentally or on purpose, put batteries in backwards.

Bill

Yes, your Malkoff is probably damaged beyond repair and cannot be repaired due to the circuit being epoxied with heat sinking material.

Bill

 

[tomcat017]

Ugh, that's what I figured. Now comes the hard part--explaining to a semi-non-flashaholic that it's going to cost him $60 to fix it :laughing:. It's too bad--I liked that light better than most of my own. Do you think it's worth trying to salvage any of the parts (emitter, reflector, etc?). Well, anyway, thank you for the help!

-Mike

 

[lasercrazy]

You know for that price it's kind of sad that polarity protection isn't included..

 

[Bullzeyebill]

Ugh, that's what I figured. Now comes the hard part--explaining to a semi-non-flashaholic that it's going to cost him $60 to fix it :laughing:. It's too bad--I liked that light better than most of my own. Do you think it's worth trying to salvage any of the parts (emitter, reflector, etc?). Well, anyway, thank you for the help!

-Mike

Email Gene Malkoff, but I think it is almost impossible to salvage parts.

Bill

 

[Bullzeyebill]

You know for that price it's kind of sad that polarity protection isn't included..

McGizmo (Don) sells lights that cost more than $500.00 that do not have protection circuits and there is a reason. The added diode for polarity protection will usually sacrifice space and efficiency. I am not an EE but a good search will turn up some good points about polarity protection vs no polarity protection in an Led light. Usually a big name company such as Surefire or Streamlight will add polarity protection to their lights since most of their lights are sold to uninformed, non flashaholic type folks. Some makers are adding mechanical polarity protection such as Led drop ins once sold by BOG. The protection was a plastic face to the + spring that kept the spring from making contact with a flat surfaced battery, such as as the negative end of a battery.

Bill

 

[Mr Happy]

I've noticed that standard (incan) Mag-Lites have polarity protection even though they don't need it. Perhaps they assume that people will often retro-fit LED drop-ins?

 

[Bullzeyebill]

Ugh, that's what I figured. Now comes the hard part--explaining to a semi-non-flashaholic that it's going to cost him $60 to fix it :laughing:. It's too bad--I liked that light better than most of my own. Do you think it's worth trying to salvage any of the parts (emitter, reflector, etc?). Well, anyway, thank you for the help!

-Mike

Mike, you needed to educate your friend on polarity issues. I am not meaning to be hard on you. CPF is more than a buy/sell place, it is also about information and us finding out how our lights work, or don't work. The information is here, and worth the looking.

Bill

 

[tomcat017]

Bill,

I told him about the polarity issue when I gave him the light. Unfortunately, I think all the info overwhelmed him (correct polarity, regulation + protected cells = no warning before shutdown, proper battery charging, how to care for LIon cells and make sure they're balanced and safe, how to deal with an all-too-frequent SF clickie failure, etc etc). He was curious about the emitter specifics too, so all in all, he had a lot of things to remember. What I needed to do was write it all down--not that it would have helped in the moment, but maybe it would have stuck better. I think we forget that for someone who is used to a maglite (this is on, this is off), quality torches are really involved. He was good with everything, and good about asking questions--just slipped up I guess.

As for polarity protection--the mechanical version is nice. I've never busted a light b/c of polarity (though I have mostly incans), but it's a nice feature. I don't know a whole lot about electronics, but I'm guessing it's the circuit that died, and not the emitter? Becasue I have accidentally run a wolf-eyes LED tailcap backwards, but it worked fine afterwards.

Thanks again everyone for all the help and input!

 

[Bullzeyebill]

I didn't mean to sound high and mighty, and I may have come across that way, cause even knowing about the dangers of reversing polarity, when it can be an issue, I have caught myself starting to put a battery in backwards in a light that does not have protection. I first learned about battery polarity issues when I was younger and playing around with maglights, and other incan lights. I would somehow put the batteries in backward and the light would not turn on, and I felt foolish. Of course, the remedy was easy, just reverse the batteries and the light worked, no harm done. Led lights changed all of that.

Bill

 

[tomcat017]

I didn't mean to sound high and mighty, and I may have come across that way, cause even knowing about the dangers of reversing polarity, when it can be an issue, I have caught myself starting to put a battery in backwards in a light that does not have protection. I first learned about battery polarity issues when I was younger and playing around with maglights, and other incan lights. I would somehow put the batteries in backward and the light would not turn on, and I felt foolish. Of course, the remedy was easy, just reverse the batteries and the light worked, no harm done. Led lights changed all of that.
Bill

I didn't think you were being high and/or mighty--no worries. And yea, we all do it at some point--it's just fortunate when it doesn't result in :candle:. I guarantee he'll check his batteries from now on. Feel bad for him, but...that's how we all learn, one thing or another. I once soldered an emmitter onto a board backwards--now I double check :laughing:

 

[Gene43]

PM sent to Tomcat.

Thanks, Gene