Galvo drift problem - newbie question

[Nevermind29]

Hi dear forum,
I'll try to describe my problem in English (I'm from Germany so please excuse my bad spelling und grammar issues). I have a problem with my galvos in my LW CS-400 rgb (as far as I know the LW 20k scanners are being used). When I operate the projector with my Medialas Hyperport V6 ILDA Interface (on Mamba 2.0) the patterns seem to "drift" around the x-axis while this effect doesn't appear on the Y-axis. It's hard for me to explain what exactly I mean, so I put a video on youtube to show the bug:

http://www.youtube.com/watch?v=JZoAGgvO46g (at 3:04 you can see this "drift" very clearly, the wave pattern should move up from the floor to the ceiling slowly but moves slightly from the left to the right and from the right to the left)

I opended the case and checked all the screws and cables, I also tried Pangolin LD2000 and another IF, but the problem is still the same. When I adjust the output settings in Mamba 2.0, I am able to reduce this "drift" a little, but then the output angle decreases. With my G-Tech 100mW G (used as Sidefills on a different mirrored IF) there is no such problem. I noticed that the problem disappears, when I reduce the scanning speed, but unfortunately the quality of the output-beam is getting very poor (I know that the whole projector is very shitty, but I like him anyway.) I noticed something else: the problem appears after a few minutes of warming up. After switching on the unit at the first time (when the parts are cool) the drift is visible, but smaller. Any ideas ?

Greetings from Germany

PS: Again please excuse my bad english...

[Doc]

First of all your English is better than many English people I know!

The problem is almost certainly a hardware component dying in your galvo amps; you could confirm this with a tin of chiller spray.

Gently spray areas of the amp whilst monitoring the output.

http://www.rapidonline.com/Tools-Fas...er-spray/28732

[-=Jim=-]

First of all your English is better than many English people I know!

Funny... the first thing that came to my mind was how much better his English was compared to mine.

Jim

[Nevermind29]

Thanks a lot for the quick reply, I will check the galvo amps today...

[300EVIL]

I have also experienced this problem with a set of LW50K scanners I had. I also agree that it's possibly an under-rated component on the amp as mine seemed to "Glitch" the most after running at high scan angle for a period of time. I did however solve the problem by turning down the scan size pot on the amps.

[-bart-]

The problem could also be located in the position detectors in the x-galvo.
You could swap the x and y amp to verify this (a retune might be required).

[santanas]

Hi, I also have a drifting and fuzzy output (SOME TIMES) It drives me nuts and projector is new and only a cheap 20 kpps scanner. I Will use this projector in other mode not ILDA which sucks with this 500mw projector from Laserworld. I have been had and I know it. I tried shorter cables to 3 ft and same effect. Good luck? JH

[Stoney3K]

Drifting outputs (fuzzy lines) can also be caused by mechanical problems, fx. mirror wobble.

I've had a little accident with my galvos -- they dropped to the floor mirror-first. Obviously snapping off the mirrors, luckily breaking the galvo's fall.

Installing new mirrrors, I found that the scan pattern was seriously blurry. The cause was the fact that I used contact adhesive that remained flexible when it's set, causing the mirrors to wobble along the galvo's axis.

Things like broken bearings (axis or thrust) and other faults can cause similar issues. First check if the problem's not an electrical one (swap out the amp for another), if the problem persists, it's either an electrical fault in the galvo or a mechanical defect.

[Nevermind29]

Today,

I took the projector apart and I didn't found anything special about the mechanics. The Chiller Spray also had no effect. So today I focused my attention on the amp tuning (I never did that before) and decreased the output size. The drifting disappeared and I'm happy now ;-) In the near future I will buy a new Scanner-Set, perhaps something more expensive... @ all: Thank you very much for the quick help !

[Doc]

Good to hear that you resolved your problem.