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My PJ is a Barco data 708

Alright, over the the past few months i've been messing around with my HTPC using different scan rates, resolutions etc. but one problem remains... when my eyes move up and down I notice green and blue flashes on relatively brint projected areas. I never see red, just blue and green. Incidently these are the two tubes that have recently be installed. When my eyes shift from side to side it's not nearly as noticable, but still seemingly present.

At first I though maybe my eyes were catching the image refreshing...

So i bumped the refresh up to 96 HZ and it was still there... I've used the G2 adjustments (think that what they are called) and all the leds are off so the tubes should be in sync....

Does anyone have any idea what is causing this?

ANY help would be awsome!
 

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I see these as well - sometimes - on my ecp 4500+.


I think it has to do with the persistence of the different phosphors - to get good brightness on green the phosphor has to glow "longer" when it's hit by the electron beam.


The problem tends to show more on very high contrast material - for example Dark City - the swinging lightbulb near the start in the bathroom.


You can reduce the effect by (I found)


- Reducing the contrast - if you're not using a screen - get one. The difference vs a white wall is AMAZING.

- Changing the refresh rate / resolution - I seem to remember 72/75hz improved matters. Pushing the refresh rate higher just seemed to cause other problems.


To be honest the problem went away after I did several full on calibrations

of the projector - re-adjusting the raster width and re-centering, full grey scale, focus...


You've just got to find the "sweet spot" of the projector.
 

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I used to get a blue flash every now and again on my ECP 3500. Since I knew nothing about projectors at the time I asked Curt because I bought the thing from him. His first question (are you using H or V move). Yep I was. I turned move off and used my HTPC (thanks Powerstrip) to do the moving and no more flashes.
 

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"move" is a function on the ecp series projectors to move the image (or raster) on all 3 CRT faces from the remote control (rather than a little resistor pot inside the projector)


It has 4 modes on my ecp 4500+ H move, V move, HV move and no move.


I'd never considered that the move circuit might be causing the problem with the flashes - but I suppose it's possible.


liquid - peer into the lenses with the brightness and contrast turned way way down and check that the image is central on the face of the crts horizontally (in all 3 tubes). If it's within 1/2 a cm or so - then that's not the problem - if it's not, then you can try and tweak it.


I'm not familar with the barco - but there should be some adjustment -

to center the "raster" on the face of the tubes. Be careful - do not move the raster outside the visible part of the tube - as the heat generated by the electron beam can crack a tube if it


I would suggest marking the adjustment before attempting any tweaking.


Or as timle points out you can use powerstrip to adjust the output timings on your computer (if you use one) to center the image.


Let us know how you get on.
 
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