CurtPalme.com Home Theater Forum

[gan]

The rasters on my BG808s are to wide
They are very close to center and there is even amount of phosphor at top and bottom but they overshoot the sides on every crt by quite a bit.
Is it possible to reduce the size of the rasters so that they fit inside the phosphor?

[Nashou66]

As long as you don't allow the actual image to go off the sides, it will actually help with long retrace timing that are used for higher bandwidths like 1080p.

Just shrink the image down via your PC or Scaler, but I am sure a Barco guy will chime in to help if you still want to reduce them.

Athanasios

[gan]

I reduced the raster widths to fit the tube face via the trimpot inside the pj
unfortunately as a direct result of this the image is now not quite as wide as the screen
at least 100 to 150mm inside the screen frame.
With the rasters as they were originally shooting off the sides the image just went over the screen edges by approx 50mm or so.For convergence and geometry this is what we should achieve right?


Its a bit of a concern for me to have the rasters overshooting the edges like that as the manual states and shows exactly where on the tube face they should be setup,along with warnings of imploding tubes if they should overshoot the phosphor.

Coming from tweaking a D50 to the Barco is quite a bit different and im more then a little apprehensive wanting to get things right.

[Nashou66]

As long as the active image is not over the edge of the tube it wont implode unless you have your G2 set too high and the raster is lit up.

Athanasios

[gan]

Cheers for helping me out here Nashou66


How do i know if G2 is set to high?

are the rasters not lit up like the active image?when doing raster centering on the barco the raster is barely lit up,i have to crank up brightness to see it,does the pj automatically drop the contrast and brightness settings when you go into raster centering?

Sorry for all the questions i just need to be sure about this before i go thru the setup.


Cheers.

[Curt Palme]

THere is a master width pot adjustment on the main SMPS that is probably out a bit. See the tips section of the main site for where it is.

I set it so that the test pattern just touches the outside edges of the phosphor. That will ensure that the image is completely within the phosphor.

[Curt Palme]

THere is a master width pot adjustment on the main SMPS that is probably out a bit. See the tips section of the main site for where it is.

I set it so that the test pattern just touches the outside edges of the phosphor. That will ensure that the image is completely within the phosphor.

[gan]

It must have been jolted during transit because on the first opportunity i checked the test pattern on the raster by looking into the lens and both the raster and test pattern were shooting off the edges (both sides) of the phosphor on each tube.
I did adjust via trimpot and managed to get both within the phosphor with some extra adjustments ie h size etc.
So all is good on that front.
However ive come across another problem,doing geometry with an external pattern or internal pattern or genlocked pattern: after all adjustments are done with the green using a x hatch pattern its perfectly centered and nice and square and straight on the screen the red and the blue should be converged very closely to the green but they are a really long way off.It appears that they are not moving with the green adjustments at all,the red especially needs what looks to me like some serious keystone adjustments and the blue not as far off but bad all the same.
Have i missed a critical step somewhere?
Or does the PJ have a physical problem?

Have added some screenshots,my photography skills are severely lacking but i hope this gets the problem across.

[RobertMfromLI]

gan:

Have you zero'd out all the convergence settings on your PJ? If your's has a Service menu, you can do it from there. I am guessing (meaning to ask Curt or someone else here) that deleting all blocks may do that as well (Curt/anyone, is that the easy way of getting around my lack of a Service menu to reset all the convergence settings? Simply delete all the blocks? Also, I am presuming from what I have read that the PJ automatically recreates the blocks it needs for it's internally generated patterns and logo screen and menus?)

I've noticed that my PJ, because each input/block has already had it's own settings/convergence done, displays each input source differently. For instance, when I displayed RGBHV via a PC at 1024x768x60Hz, everything was shifted far left and the left side had major keystone and bow issues - as well as major raster "drift" of the other colors (much like your right side). That was after aligning everything via the "Installation" phase. I fixed that (well, mostly) but when I switched to S-Video, everything was shifted left and there were entirely different convergence issues. Switching back to RGBHV and that was still "fine" (ie: as good as I got it till I decided I was done with it for now).

So, it seems that each block (ie: each input used plus it's resolution/refresh) stores it's own convergence, raster positions and such.

The other thing I noticed is that if I do large raster shifts (or sizing) of the green, then though the blue and red follow, the convergence gets messed up - I would definitely do raster shifting, sizing and alignment before convergence. Following the Installation prompts I think does it in the "correct" order. Also, raster shifting or size corrections seem to affect each other.

Best,
Rob

[perisoft]

Convergence is the last step.

If you adjust the trim pots for size / raster position for the R and B, you can get things sized and centered basically correctly before you do convergence. You can adjust R and B position vs. G with fine convergence, but it's best to keep those adjustments to a minimum if possible. At least, that's the dogma, and I don't question it despite my not being aware of the technical details!

You can adjust raster size during 'guided setup', although the menus are a pain in the ass.

And Robert is right; adjusting any geometry will hose your convergence to some extent and you'll need to tweak it. That's normal.