i think i farked it.

[afaridan]

hey,
im one of those guys, the ones that dont really know much but thinks... yeah ill just do a bit of tweaking and it will be heaps better...

story is...

i bought a green laser pointer off ebay the other day.

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&ih=015&sspagename=STRK%3AMEWN%3AIT&viewitem=&item=250081710179&rd=1&rd=1

the beam wasnt bright enough. i just wanna be able to see the beam EASILY in the dark.
not just the pointer but the whole beam, light saber type thing.

so i googled...
http://www.plans-kits.com/lasers.html
i found.

so i pulled apart the laser pointer, turned the knob/potentiometer (fancy word for variable resistor?)

and now, all i get it a red dot comming out of the beam.(yes a red dot)
that will not shoot out at all. just visible if you look into the beam.
no nothing.

so the question is, have i farked it?
what can i do to get it to work again?
and what can i do to get max power out of it?
i tried different batteries, 2 batteries that came with it,
2 rechargable batteries, and 2 new batteries that i measured to have 1.56 volts each.

i know a bit about electronics but dont know the names of some components.

as i turn the potentiometer i get a varyance in resistance, still no diffrence in output light,
voltage drops to 2.8 volts when button pressed.

what do you recomend?

thank you.
-matt afaridan.

 

[Rubycon]

NEVER stare into a laser even if doesn't appear to be working!

If there's no IR filter present you could damage your eyes irreversibly in short order! That dim red glow is from the pump diode. Lack of green could mean the MCA fractured or the pump diode has facet damage and is not producing enough IR for green or has changed modes (from facet damage due to over driving) where the "sweet spot" of the MCA is not getting lased.

Turning the pot isn't as easy as it sounds. One MUST carefully monitor the pump drive current at ALL TIMES and monitor the green output expanded for mode changes as well. Proper eye protection is a must as class IIIb levels can cause eye damage faster than your blink responses.

Sounds like the laser's dead though.

 

[dr_lava]

Rubycon+

Also, if you couldn't see the beam easily in the dark, it probably wasn't true 30mW green output.

 

[afaridan]

"pump drive current at ALL TIMES and monitor the green output expanded for mode changes as well"

what is the pump drive?
what is the green output?

how can i reverse what i have done?

 

[dr_lava]

pump dirve is the laser current draw. green output is the laser beam power output that is not IR. to reverse it you need to buy a 5.6mm 200mW 808nm diode from ebay and get out your soldering gun.

 

[afaridan]

" MCA fractured" ?
whats that?

 

[Rubycon]

MCA = Monolithic Crystal Assembly. With small DPSS lasers the KTP and Vanadate crystals are glued together for simplicity and cost saving. It makes the unit more rugged as there is one less part that can get knocked out of alignment. Aligning discrete KTP/Vanadate elements can be a real PIA without special tools.

Small MCA's used in pointers have a rather limited capacity for handling the 808 nM pump power. This 808 is typically focused to a very small spot with a GRIN lens and the MCA can overheat very quickly if driven far past the designed power. Some MCA's can also experience failure when the adhesive used to bond the KTP and Vanadate pieces together darkens and absorbs even more energy. This runaway will spell death quickly if it's allowed to continue.

See this part of Sam Goldwasser's Laser FAQ for more information:

http://www.repairfaq.org/sam/lasercds.htm#cdstoc

 

[Fluffster]

so i pulled apart the laser pointer

Is it possible that the OP has removed the crystal altogether and forgot to put it back in, thus ending up with an IR laser?

 

[afaridan]

Re: i think i farked it.

--------------------------------------------------------------------------------

Quote:
so i pulled apart the laser pointer


Is it possible that the OP has removed the crystal altogether and forgot to put it back in, thus ending up with an IR laser?

well i havent put the thing back together. im just operating it in my hand.
and im getting the red dot shining out of the pointer but no green.
if i turn the potentiometer to some parts i dont even get the red dot. so it has to be in a certain spot for it to work at all.

 

[FloggedSynapse]

Yes, you f*cuked it.

You're probably seeing the 808nm output from the pump diode. It may appear faint but this is only because your eye is very insensitive to radiation at this frequency. It's near-IR. Just be careful cuz there's still enough energy there to sear your retina.