Fading Green Diagnostic Help

[keebs]

Hi,

I have two of "the same" TTL, RGB projectors: fairly low cost/power and US legal (because I'm still in discussions with them, I'll leave any brand names out). One unit works well, but the other unit has an issue where the green fades in certain situations. It doesn't happen with all patterns, but a good example of this can be consistently reproduced using the Cue 13 from the "Fans of Beams" page in Quickshow / Beyond (for all of this, I'm using an FB3 w/ Beyond). To make the issue more clear, I modified this synthesized pattern to be simply a half circle of white points as shown:



With this configuration, starting from the left side, the output points from the bad projector are white and as you make your way clock wise towards the other side the white fades to purple and by the far right side, it appears fully purple (indicating the green output is lowered significantly). Using the other projector, all points look pretty damn close to equal in whiteness and brightness, so I think this rules out any software settings or issues with my FB3.

Here are the two outputs... I think which is which will be pretty obvious





Changing the color effect in the synthesized image to create a full circle of points eliminates the fading effect.

Unfortunately, I can't open the projector up and get an oscilloscope in there due to warranty issues, so I was hoping somebody on here could offer some words of wisdom. Module? Driver? Something else?

And just to make sure I'm not crazy: would you agree this isn't acceptable performance for a unit just received from the manufacturer, even for an entry level unit?

Thanks very much for your input,

Todd Keebs

[dave]

Looks like a a issue with modulation speed. I would send the laser back and get it sorted out

[kecked]

temp issue on the dpss laser. tec is bad.

[keebs]

temp issue on the dpss laser. tec is bad.

Do all projectors have TEC's? This is what I'd call a "budget" unit, so I wouldn't be surprised if it didnt have one.

-Todd Keebs

[badger1666]

What powers are the lasers ?
I had the same problem with a laserwave green , few tweeks to tec temp and it was fixed
If yours is that budget it does not have a tec it could be a badly mounted xtal and suffering heat transfer problems
Open up the case and post a pic of the offending laser and driver

[keebs]

Hey Badger,

This has a 50 mW green in it. Unfortunately I can't open the it up without voiding the warranty.

The manufacturer issued an RMA, so I'll be sending it back and hopefully sorting out the issue.

Thanks for the responses, it's much appreciated.

Todd