2 of the same rgb scanners 2 different hues of white

[Mikey851]

I have two rgb scanners made by the same manufacturer. One of them produces a white with a blue hue and the other produces a white with a green hue. They are both equal intensity and it doesn't look bad; I was just wondering what could cause it.

Could it be that the resistor is set so that the green diode is putting out more power than the green diode on the other scanner thereby causing the white to have a green hue?

Thanks in advance for any help.

[dnar]

Yep, in each projector one colour laser is producing a little more power. It doesn't take much of an imbalance to change the "white" balance.

If you have details on the laser drivers, you could back off the blue and green lasers a small amount to correct.

[dave]

Cheap crapy Chinese RGB's?

[Mikey851]

Cheap yes........crappy no. They look GREAT for the price. Don't get me wrong, in the future I want to build my own scanners with premium parts.....I just can't afford it right now.

[ShortyInCanada]

As always...how about some pictures of the afflicted units and perhaps a side-by-side comparison ?
(Actually I just want to see two units side by side doin' their thing. )

[Mikey851]

Oh good idea; I don't have any still photos so i'll get some next time I'm at the shop. I would just take a snapshot of a video but it doesn't look as good. Plus I haven't taken any videos since I got Quickshow (great program might I add).

[Mikey851]

Here's a shot of both white. You can't even tell the difference in the pic.....although I should have done a fan of beams....sorry about that. In person however you can seen the slight differences in the hues.

[Mikey851]

Here's another one. Sorry about the single colors, I was programming some patterns and being lazy. Next time I will make a fan with all of the colors so you can see what it can do.

[Mikey851]

And one with some text going through cheesecloth.

[norty303]

The problem is usually with the DPSS heads, as even at the same power, they can easily have different modulation characteristics - and this is not just the domain of the cheap heads. This becomes more apparent the lower the power of the projector, as any difference in rise speed, etc can be a higher percentage of the overall power of the projector. I've turned over a few DPSS 532 heads trying to get a good match for a pair of projectors.