CurtPalme.com Home Theater Forum

Mark_A_W · Posted: Mon Sep 03, 2007 10:17 pm Post subject:

"Remember use the video input "...with the horizontal amplitude at +100%.

You shouldn't have needed to do this. If the image is wider than the raster (wrapping) it will make no difference.
Image wrap is porches, or the blanking is too far in (and it's not really wrapping at all).

Anyway, it's not hard. Multimeter, video input (ordinary DVD player), width at +100%, 1.8v on PA pin2, done.

whats6x7 · Joined: 04 Oct 2006 Posts: 5924

OK, Maybe I'm missing something simple then. At 120" the screen video is way too wide for my 84" wide 16:9 Wilsonart screen. Amplitude will not make it small enough, the porch settings appear to be correct, the Horizontal Width pot works. Is there something else to make the video smaller inside the raster? It isn't that the video is wider than the raster, it is almost to the edge.

Position moved it around inside the raster, does something else control the size?

dbaisey · Posted: Mon Sep 03, 2007 11:37 pm Post subject:

What was the voltage? May be fine but doesn't hurt to be sure. Doug
The porches control the width of the image in the raster. The H Width pot is the global voltage spec for the projectors raster width.

whats6x7 · Joined: 04 Oct 2006 Posts: 5924

Haven't checked yet. Kids go to bed in about an hour. Here is what I don't understand. The raster width was about right in the tube face (not too big), the video fit inside the raster, so why was the image too big on the screen?

dbaisey · Posted: Tue Sep 04, 2007 12:10 am Post subject:

Porches or the raster is to wide. You should be able to adjust the image size within the raster from the source settings. Doug

Im not good with HTPC settings but Mark is.

whats6x7 · Joined: 04 Oct 2006 Posts: 5924

Raster is fine (I think) but I'll play with the porches like you and Mark have suggested. Will that also change the size of the internal test pattern? I'm also going to check the voltage. If the voltage is OK I should be fine using the H-Width, right?

dbaisey · Posted: Tue Sep 04, 2007 12:22 am Post subject:

If the voltage is ok then something isnt right. The internal test patterns are wider by 10% or so you have to use the actual signal to fit the screen size. Doug

You might get a better idea of what is going on when you have the video input projecting from a DVD player. If it looks normal then I would say the HTPC settings are the problem

whats6x7 · Joined: 04 Oct 2006 Posts: 5924

OK, The kids will be in bed in the next 30 minutes. I'm going to set it back like it was and use the Porch settings to see if that helps. Please tell me one more time in a little more detail whre to find pin 2 in relation to the horizontal width control.

dbaisey · Posted: Tue Sep 04, 2007 12:33 am Post subject:

The front most side of the deflection board is the PA white connector. Pin 2 is the middle one.

Mark_A_W · Posted: Tue Sep 04, 2007 2:22 am Post subject:

With optimised porch settings the image will be about 4mm from the edge of the raster. You may find it's better to offset the image slightly to avoid the kink in the LH side (on the screen) which is due to beam settling after retrace.

The numbers you posted earlier look fine, although the 56 pixel sync width is a little low, I like 128. But I think this is irrelevant.

It does sound like the H-width pot has been tweaked. The only other reason I know for a too wide image is low HV, which is very unlikely.

Check your width pot.

whats6x7 · Joined: 04 Oct 2006 Posts: 5924

2 things . . .

1. Christ this is a lot of work!
2. It is at 1.8 now and everything is fine. I guess someone tweaked it before I got it.

Thanks for all the help. I was going to keep one and sell the other one but I think I'll hang on to both. I have a storage room in my basement that is 8' wide and 20' long. I'm thinking of making a mini home-theatre room for the kids.

Mark, you said the image should be about 4mm away from the edge. I'm going to pull the lenses again to check. I know you should never have the image go off the side of the tube but is there any danger from the image being off the side of the raster? Just curious.

I'm sure I'll bug you guys with some more questions but I'm beginning to see the light at the end of the tunnel on this one. Last night I was seriously considering giving the second 9PG to anyone who could come set this one up. Now I don't have to do that. Smile

Mark_A_W · Posted: Tue Sep 04, 2007 5:03 am Post subject:

No, no danger with the image going off the raster, but it doesn't look good.
Try it, just crank the shift over till it wraps back on itself, or piles into a bright-ish line.

And 4mm-6mm is ok. 12mm+ is a waste.