Replacing Motor In A Laser Projector

"The motor seems to have blown so i want to replace it."

Why replace the motor? You are not yet certain that effort will fix the trouble.

Power supply/transformer? Switch? Is there some interlock with the light source?

The lens just needs to be turned - the laser works just fine. so i just need to make a motor turn a couple gears and i know it will work --> i can turn it manually and it works.

Can you measure the DC voltage on the motor terminals when it's supposed to be turning?

It could be that the motor is "pulling down" the voltage: so you might have to cut the wires and measure them with the motor missing.

are you saying that the laser would be getting too much voltage because the motor would have been taking some? What if i just leave the broken motor there while having the new one do the actual cranking? Otherwise i would need some kind of resistor? i would rather not go that route as i would need measuring tools for one and a resistor for another and i dont feel like buying them.

No, Randall is telling you the same thing I said in post #1: Check to see if there is 12VDC being supplied to the motor now. It may be the transformer, not the motor. It may be the switch (if there is one) that energizes the motor.

I think a resistor the appropriate size is about $0.25 or so. I also doubt a line resistor is necessary to operate the thing.

Hmmm, even if it is a transformer, i wouldnt know how to go about fixing that. it would probably require some amount of soldering on the tiny circuit board, no? (i dont know anything about these things) and again, i dont have the tools to check voltage so i dont know if it is being supplied to the motor or not. i figured it would just be easier to get a new motor to turn the thing.

If the transformer is not providing the required power, you can isolate it (cut the wires and insulate the ends, NOT together) and simply add the battery array as previously discussed.

You can check for output by using a 12 volt auto lamp (turn signal or such).

Having no test equipment of any sort is kind of hindering this little project.

The replacement motor you linked to was, I think, about 12 bucks. Add a little shipping and tax, probably twenty bucks by the time you get it. 6 volt lantern batteries are about 5 bucks each, I think. Is this projector (new) about $60.00?

Alright, i see what you are saying now. It seems i have to way my options or rather see if i can borrow some equipment from my school (i'm sure there is a voltage meter somewhere on campus - im a psych major tho so i wouldnt normally have access) A new laser would be $60 yes, so i would rather not do that especially if it will just break again. Thanks for all the help!

There you go! Diagnose the real trouble before you replace a bunch of parts that do not help the problem.

When checking the output of the power supply, also check the resistance thru the two wires that go to the motor. I would expect that reading to be about 120 ohms. Disregard: That is just a wild guess... measure the resistance and report back here. If the resistance is low (say, 6 ohm), the motor is bad. If resistance is infinite (no reading at all) or very high, motor is bad.

To answer this part of the question, "if i could power this motor with a 9 volt battery or something." Yes, you'd need 12 volts. That takes 8, 1.5 volt cells (size is your choice), or a 9v and two AAA, AA, C, D, two 6V lantern batteries. Or what-have-you that = 12v. No need to solder, use alligator clips.

sounds good on the battery aspect then, thanks. anybody know if the motor is the right choice?

Is this another "busted" law of physics?

Is it possible to split a laser beam and get a rainbow?

There's something fishy here. (or am I just getting paranoid?)

Maybe the light source is not a laser.

I hope this isn't Joe's alter ego. (Gearboxes and such)

http://www.spencersonline.com/product/*hf-green-laser-kaleidoscope/

This is not a kaleidoscope effect. It's simply passing a green laser through 2 holographic diffraction gratings that produces multi-dot pattern. One diffraction grating is mounted to a fixed point (the case) and the other is mounted in a cheap, plastic geared motor assembly that's designed to fail in short order (crappy disposable product from China).