95 mw viper/infinity problems

hi. i have a 95 mw 532 nm laser from techlasers (wich no longer exists) but is exactly the viper model from dragonlasers. the problem i have lately with this laser are related (i think) to the battery. i put 2 freshly charged Ni-MH recharchable AAA's in it and it simply dosent work, or sometimes it flashes and then dark again. when i change the battery with some alkaline ones it works perfectly fine. the voltage of the Ni-MH's are 1.5-1.6 volts and the alkaline (not brand new) is around 1.4 volts. another issue is that it is unstable when i hold it from the head of the laser, sometimes allmost turning it off. when that happens, I try to move the top of the laser up and down (it stays still tough) untill i find the "balance" when the beam is the brightest.

I really have the feeling that this 2 issues are in fact a problem with the casing of the module and driver.

Did annyone here had a similar problem with a viper series (or infinity from techlasers) ?

What is most likely to cause this behavior ?

1. Ni-MH batteries are 1.2v
2. did you measure the batteries with a multimeter?
if you didnt, then you may have dead Ni-MH's or dead charger

i mesured with the multimeter. its >1.5 volts after about an hour i removed them from the charger. i dont have other rechargable, only alkaline ones to see if the rechargables are damaged somehow. they are about 2 years old tough... maybe they give voltage but when it comes to curent drain = fail.
if i put a normal alkaline battery and one of those rechargables it works on about 5-10 mW output.

i removed the front end today to reach the driver (it was preety hard to pull it out).
if i want to overdrive it, when do i know i reached the limit of the diode output ?

and another thing i dont know: the driver take its "+" from the battery through the laser body ?

Fully charged and unloaded NiMH should be around 1.3-1.4V.

I suspect the problem is not the batteries but the electrical contact.
My guess is that the batteries are not long enough to make good contact with the spring and the battery cap which could cause intermittent output. But it doesn't hurt to use new batteries. I use Sanyo 1000mAh NiMH AAAs.

Try stuffing a ball of foil in the gold battery cap and then try the NiMH.
I had this problem with a laser once. I cut off 1/8" solder wire and welded it onto the inside of the battery cap by gently heating it with a butane torch (far away from the flame so as not to damage the metal finish) until the solder melted. I never had a problem after that.

Before you make any modifications and ruin your laser, put it back together and don't mess with it. These lasers are very easy to damage or destroy if you do not know how to disassemble them properly.
Also, by taking it apart, you may make the electrical continuity worse by exposing the brass to air and body oils which will oxidize and corrode the metals making them more electrically resistive. Furthermore, if the parts are loose, they may be prone to falling apart on their own or wobbling around which also is not good. Pressure from the spring and batteries may be enough to pop the module out of the laser casing while you are using it or just cause poor contact with the batteries. A small dab of 2 part epoxy in one spot (never super glue or any cyanoacrylate adhesive!) should keep everything fixed in place.

1. Yes the drive usually takes its + from the body of the laser. Most of the time.
2. Sometimes on these old lasers the contacts get dirty. This includes the threads on the body of the laser. Take a pencil eraser and clean all the threads, and battery contact points. Both on the batteries, and the host.

10x.
i will buy some new Ni-MH's aswel. il be back here if same thing happens with new batteries + clean contacts.