Marquee Modification Performance enhancement thread

The NEC PGs had two magnet rings at the back of the deflection yoke those served as mechanical raster centering, this was of course backed up by full electronic centering as well.

Now the instability of the Marquee electronic centering is more of an electronic design flaw than anything else, that can be aided if needed (whatever yokes are used)

The moome card will accept any resolution you can trow at it as long its under the max pixel clock, wich is not a hard limit, normaly between 200-220Mhz.

4K or whatever in between is totaly unrealistic for CRT, everyone that has setup a CRT to run 200Mhz knows how much more dificoult it gets every time you increase the bandwidth a bit, and pushing the bandwidth over the videochains capability reduces the resolution, so its like kicking yourself in the ass.

So Chris i think you should start buying a Radiance pro, and figure out how 4K works, WCG HDR10/ DV and explain how your thinking it will be worth the time on a 120-150Mhz capable projector, and if you run VDC neckboards u better keep it below 150Mhz or they will overheat and self destruct.

We have a 200mhz capable moome with a simple filter change, and it will do 12 bit, sure more headroome would be nice, but doubt it would be worth moomes time, and it will ever be good buisness. The biggest bottleneck is the marquee videochain.

I can run 330Mhz from the test generator, and it will display a decently looking image, but far from resolving the signal, on a standard CRT projector you might get better results running something like 720-960P 60hz instead, it will be sharper and easier to controle.

And still the mecanical raster centering is needet to generate less heat, and prevent convergence drift and shaky unstable image. Specially if you care about image quality/ no raster ringing.

So Kurt. Tell us what you would do for someone who had a stock 9500 and you were to transform it into your ultimate machine.

Sounds great. Can't wait to hear more about your G90 Project.

Ultimate is not realy easy, but ill say as a basic you would like a early Ultra machine, or preferable from before 2003, then you should have a good standard machine with good quality boards. You should remove the 3 resistor line mod on the vim, and the peakingtrimpods.
Then you make sure glycol is pure, most marquee focus issues is glycol related, or pushing to high pixelclock will make it softer, specially on the sides.. Gjaky helped locate 3 resistors on the FGM that alows to change the range of the side focus, its a good simple mod to improve range on the sides running high pixel clock, but have to be used gently, as it will trow off focus in other zones, so its a compromise, but overall a small improvement in focus uniformity.

I have not had time to finish testing Gjakys mods, but hopfully will before to long, and im pretty confident they will give a video chain improvement.
Generally you need to be carefull with Marquee mods, most change the imge, but mostly it gives some and take away more.

So start with a good helthy Marquee with lcp tubes, prefered 2/4 pole flaremagnets, avoid the 6 pole ring it often generate more confusinon than it helps. Set flare magnets using a source generated patter, and it will take loads of time ofsetting the raster, and setting the flaremagnets, but it is ine of the most critical marquee setup procedures, and see to the horizontal deflection yoke is aligned so no skew is needet on any of the colors.
If you keep your bandwith down at a level that is easy on the Marquee you get a awsome image from a standard projector with verry little mod work.. 

Would sure be nice if there is a fix, but as is, and always has been with the Marquee we will need to work with what we have and get the best of it. fixing the ringing would save bandwidth wich will ultimately also sharpen up the image, 180Mhz to 195Mhz is adding quite some to the setup challenge.