green laser dim after a bit

so i bought a green laser for 8 bucks on ebay, but it's actually not really a cheap quality compared to other green lasers i've bought from ebay. it's very bright, but after about 10 minutes or more the laser dot is dim as if the battery is low. if i put the battery is a different laser it works perfectly.

and also, it seems if i unscrew the laser for a bit then put it back together and try it again the beam is bright again. and if i don't use it for a while (like a few hours) then try it the beam is dim again.

can someone explain this?

usm6836 said:

so i bought a green laser for 8 bucks on ebay, but it's actually not really a cheap quality compared to other green lasers i've bought from ebay. it's very bright, but after about 10 minutes or more the laser dot is dim as if the battery is low. if i put the battery is a different laser it works perfectly.

and also, it seems if i unscrew the laser for a bit then put it back together and try it again the beam is bright again. and if i don't use it for a while (like a few hours) then try it the beam is dim again.

can someone explain this?

Click to expand...

There may be a couple of different things happening.

As the laser heats up, the metals in the module and host expand. This changes the alignment of the crystals. When you let it cool down the crytals return to their correct position.

There could be also a connection that heats up and fails or a component that fails with heat.

Pointers are not really designed to be used for long periods. Limit the time it is on to protect it (e.g. 30 seconds on - 60 seconds off). Sometimes once the metals expand they never return to the exact same position. The same can hold true with components. One of the times that it fails due to heat, it may not come back at all.

Peace,
dave

I had this exact same problem with 2 eBay green lasers.

It turned out to be the little contact spring. I don't know how or why, but when I pulled the spring out a little bit (using a paperclip) it fixed the issue on both units, now they don't dim at all.

Mine were dimming almost right away btw, like 2-3 seconds after powering them on, they would dim.

i have 2 greenies that do the same..
i wasnt/still arent sure whats wrong with them