XG owners: please help compile a how-to guide! - Page 15 - AVS | Home Theater Discussions And Reviews
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CRT Projectors > XG owners: please help compile a how-to guide!
Doug Baisey's Avatar Doug Baisey 08:50 PM 11-20-2004
Hit the info button and confirm 15.75 khz. Doug
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Doug Baisey's Avatar Doug Baisey 08:54 PM 11-20-2004
Cant see it in the 720P photo you just posted, not enough light to see the tube face. Doug
garyfritz's Avatar garyfritz 09:13 PM 11-20-2004
Post #411: voltage at pin 1 is 4.13V. Have we changed something that needs a recheck? Centering it on the screen again maybe? The current video voltage with the image sized to the screen, no overscan, is 3.86V. With 13% overscan it's still 4.13V.

Info button says 15.74 kHz.

I don't know how you want it centered. In the up-down direction, the center of the image (the dot right above the 1.85:1) is above the center of the CRT (measuring from the little bumps on the left-right center of the bezel), but the raster seems to be a bit low. Should I raise the raster and lower the image?

Left-right, it's a bit closer to the right than the left, but the lower right corner sticks out a bit. Not sure why, given the 720p raster is pretty symmetric. (See attached for current 720p raster, disregard the previous link. Yellow lines mark the edges of the tube face. This one has some keystoning -- apparently I'm not shooting it straight on.)

Linearity: this image is not perfect yet. The lower-right corner is squished a bit and I haven't figured out how to fix it without messing up other areas. But you're right, the linearity is not great. E.g. I just measured the width of boxes on the center line, and the boxes in the middle are larger than the boxes on the ends, and boxes on both ends are about the same. Neither linearity nor amplitude will fix that, right?

What **IS** DC H Linearity, and how/why/when would I use it?
Doug Baisey's Avatar Doug Baisey 09:18 PM 11-20-2004
Yes, you had 13% overscanned before. Now you have amplitude set for your screen size and why we need to check it again. Doug

Hang on a few minutes while I check what I have. Doug
garyfritz's Avatar garyfritz 09:20 PM 11-20-2004
OK. It's 3.86V now.
Doug Baisey's Avatar Doug Baisey 09:22 PM 11-20-2004
You have a oddity but I want to check something at that voltage. Bring up the 720P signal and see if it fills the screen. Doug
garyfritz's Avatar garyfritz 09:26 PM 11-20-2004
Hm, no. It's a tiny bit shorter in the V direction, but almost a square (in the Avia 1.85:1 crosshatch) narrower on each side. Somewhere the cranking on RV5302 or AMPLITUDE must have changed it?
Doug Baisey's Avatar Doug Baisey 09:29 PM 11-20-2004
DC H Linrarity is at the button of the alignment menu. It's sole function is to help off set linearity on green geometry (overall) the reason its not talked about in the service manual is because it can screw you up if you dont understand when to say uncle. Use it sparingly and just do minor changes. If you do a data copy it can get ugly with curruption. Doug
Doug Baisey's Avatar Doug Baisey 09:32 PM 11-20-2004
Im getting you a voltage to use. Hang on. Doug
garyfritz's Avatar garyfritz 09:33 PM 11-20-2004
Sounds like something I shouldn't mess with. Unless I really notice a serious problem with linearity, I'll leave well enough alone. I don't think the 720p linearity was as bad.

OK, if you're done checking stuff, I'm going to pop the green lens back on and fix up my 720p alignment. I assume I should leave VR5302 where I set it before, and fix the H size with the AMPLITUDE?

Whoops, ok, hanging on.
Doug Baisey's Avatar Doug Baisey 09:42 PM 11-20-2004
You are getting some weird voltages as you go through the readings, they are off from what Im getting following each with you and at your throw and screen size.

I would use case 2 as you did before but set to 4.3V (pin 1) then take the TP5302 readings. Im monitoring the heat also so that is playing a role.

Im not quite sure why your overscan isnt bringing into spec. You did confirm the DVD player setting right using your computer monitor? Doug
garyfritz's Avatar garyfritz 09:56 PM 11-20-2004
OK, while displaying VIDEO signal, adjust VR5301 to 4.3V on pin 1, NOT 4.5V as the SM says. FWIW that results in almost a square overscan on each side in VIDEO, but restores the 720p image back to full size. Then read the voltage on TP5302/TPGND: 7.20V.

What are we trying to fix here, anyway??

The room is too darn hot. The HT is very near the furnace and I can't shut down the vent enough to keep it from blasting heat in there -- which is the last thing I need when the XG is pumping jillions of joules into the room. I may have to stuff the vent full of something to cut down the flow. Might mean the room is cold when I'm not running the PJ, but oh well...

I can see the difference between 720p and NTSC. It's real obvious. The monitor wouldn't tell me any more. Less, in fact, since with the XG I can verify the H frequency &etc. It's 15.74 kHz, just like it should be.

OK, I'm gonna put the green back on and patch up my 720p alignment. Will check in if you have more to add.
Doug Baisey's Avatar Doug Baisey 10:22 PM 11-20-2004
Id leave it there (4.3V) for a day or so. We are trying to keep it from over heating the deflection heat sync. Something isnt exactly right yet but it might save the HOT and diodes in case there is a problem.

The projector has a spec and also follows optical spec. Right now yours isnt so play it safe. If you have a oven thermometer that has a thin metal stand it fits perfect in the slot between the heat sync plates. See if it stays below 120 degrees. If it does then its a good thing.

If a stored amplitude setting was over riding actual signal properties needed that could be a problem as well and non actual width settings being accurate in the Momo or if its running on non default values. I dont know that so I cant tell you what the problem is yet.

Its beer time. Doug
garyfritz's Avatar garyfritz 10:34 PM 11-20-2004
Sounds good. My mom is coming to visit tomorrow so for a while I'll probably be more interested in watching movies than tearing the projector apart. Thanks for the help!

Doug Baisey's Avatar Doug Baisey 08:58 AM 11-21-2004
Just wondering what your overscan % looks like now at max amplitude on the video input. See if you can duplicate what happened the other day when it acted up. I'd be thinking on how to resolve the heat in the room while your watching movies today.

Nascar day today so Ill be doing the same thing, watching. Doug
garyfritz's Avatar garyfritz 03:15 PM 11-21-2004
Um, at max amplitude it will be overscanning a fair amount I think, since with the default settings (whatever was there as a result of the 720p setup) it overscans a fair amount, at least 10-15% or so. If I max it, it will overscan more. I'll try to remember to check it when I fire up the projector.

I'm going to mostly block the furnace vent. The room might get a bit chilly when I'm not using it, but who cares? It will warm up fast when the projector's on. :)
garyfritz's Avatar garyfritz 10:31 AM 11-22-2004
Let's give Doug a rest for a few days, and I'll ask some questions that other people can answer. (If anybody but Pete is still following this thread. :))

1. How do you set up bright/contrast & whatever to get good picture quality and minimize wear?

I have a good picture on 720p. Bright scenes are clear, dark scenes are clear, as I explained in post #377. No black or white crush as far as I can see.

But to get this, I have the brightness set to 60, and this causes the back raster to be visible. Which means the CRT cannot go all the way to "black" like CRTs are supposed to. In really dark scenes I can see the raster overscanning onto the dark wall. This is really distracting. (Probably not for anybody else, but it is for me. :))

Also, the 3 rasters DO NOT light up at the same brightness level. Which I think means my Bright Bias is off, right?

I should be able to get good images without the raster visible, right? (How??) And it should also reduce wear on my tubes. If I just drop the brightness to where the rasters disappear, then dark scenes lose a lot of detail.

Jrobbo's explanation says the Bright Gain should be set so that the raster just barely light up when the Brightness is at the "correct" setting. What's "correct" ?

2. Along those lines, what is the difference between the Kelvin controls and the AWB controls? Are the AWB settings global and the Kelvin controls tweak individual memory slots, or...?

3. I have a lot of raster around the image. The raster overscanning on the wall extends for something like 15-20" outside the 89" wide screen. Too wide for a black frame to hide it.

Am I correct in assuming that you don't want much raster outside the image area? See my 720p raster for an example. Does this look right, or should the image be filling more of the raster?

I suppose the ideal situation would be to move the pj forward until the image fills more of the tube face. I'm not likely to do that anytime soon -- moving it more than a few inches will involve a major project -- but I would at least like to reduce the amount of raster around the image so I don't see it overscanning onto the wall. AMPLITUDE (and its identical clone POSITION -> IMAGE SIZE) adjusts the whole raster. How can I increase the image size without increasing the raster size?

4. In that raster example, the dark area around the grid is raster, and the lighter area is raster where I've pulled the blanking in. How close should I bring the blanking into the image area -- right up against the image?

garyfritz's Avatar garyfritz 08:19 AM 11-23-2004
No takers? Is anybody reading this thread any more, or should I start a new one?
pwentz3l's Avatar pwentz3l 03:41 PM 11-23-2004

I am swamped at work. Leaving tomorrow to go see my parents. My initial take on your post # 437 is that it should be the start of a new thread. There is a lot of information there that is pertinent to all projectors, not just XG's, so you might get some additional input.

garyfritz's Avatar garyfritz 09:57 AM 11-24-2004
Yup, I think so too. Maybe we can close this thread out, finally. :)
Doug Baisey's Avatar Doug Baisey 10:30 AM 11-24-2004
Before you post a new thread try to read what Avia was was intended for and also read over this thread again. Verify that you have the Momo set up right from the DVD hardware section also. Still a couple of un-answered questions here but we made it before 500 posts. Doug
garyfritz's Avatar garyfritz 11:09 AM 11-24-2004
Yes, I haven't dived into Avia yet, other than using a few of its test patterns. I'll try to sit down and watch through the various setup sections soon. The Momo should be set up properly, since I'm using the stock 720p settings. Haven't tweaked anything at all because there aren't any things to tweak with the stock settings.

I'll be going back over this thread too. With increased understanding, I suspect parts will make sense now that didn't make sense before.

Doug Baisey's Avatar Doug Baisey 11:49 AM 11-24-2004
The things to check for is the temp of the heat sync thats on the deflection board, I posted the temps I had but that was table top but still in the ceiling configuration

Video input:
Why your allowed 13% overscan is so far out of voltage spec on the video input. If you hooked up your TV to the Momo using video it should show if its configured right.

RGB input:
Hook up the Momo to your computer monitor and see what that does at 720P. You cant speculate about these things because you need to confirm it. Without doing that I cant help much more then I have already.

This has specific test patterns to set brightness and contrast, you first need to see if Avia has known issues with the Momo and that the Momo is putting out nulled settings (not processed) as a start point.

Check all settings and output formats, make sure its on the right input and output configuration, ask members that use this unit.

The projector may have used a memory setting that was stored to large to begin with. If you change the H Width pot the amplitude memory wouldnt be right. Think about this for a day or so but before you really know for sure you need a signal generator or to confirm the source is set right so you have a good reference to start with. If the other displays are ok then its most likely the projectors memory that was built wrong for that input or freq.

You cant skip over things because its convenient not to do research, it will show after your done or put the projector down. Doug
garyfritz's Avatar garyfritz 03:53 PM 11-24-2004
Doug, I am NOT trying to skip research just because I'm lazy. I just have no idea where to look.

Case in point: You say my video input voltages are out of spec. OK, what's the *correct* voltage spec? Where can I research it? The adjustment method on 10-11 just says what level to set them at, and I can easily set it to those levels. But you say it's out of spec, though you don't explain why. The manual doesn't say how they interact or what's in spec or what the projected image (in video NTSC & RGB 720p) should look like when it's in or out of spec. The circuit description says nothing about these voltages. I'm not capable of reverse-engineering the projector from the schematics. Give me some idea where I should be looking and I'll be happy to do the research. But I have a strong suspicion that information only exists in the NEC training classes, and in your head. How do I research that??

RGB: I don't know what you want me to confirm. The image looks OK on the monitor, maybe a little bleed of the blue? Some edge effects / ringing maybe? Here's a pic of the Color Decoder in Avia. Notice the edge effects in the squares. (It's actually more visible than these pictures show. All color squares are similar.)

Memory: we cleared it out, so there shouldn't have been anything stored there, should there? You had me adjust the H width pot, so you know what's going on there better than I do. Again, I don't see any descriptions of what that SHOULD be doing, so thinking about it for a day won't get me very far.

I'm 99% certain the Momo is a reliable signal source but I will try to find a signal generator. Of course, other than a few procedures in chapter 10, I have no idea what I should do with it.

Either I need to find a source of this information you want me to research, or I need to accept the projector in its current state because there's not much I can do about it. If I can't find the former, I'm pretty much stuck with the latter.

Doug Baisey's Avatar Doug Baisey 04:41 PM 11-24-2004
Case in point:
Source information, Page 3-4 shows the installation set up for your model number. This is what the lenses can do at what throw. You have 120" of throw and page 10-11 case 1. shows what to set it at but you end up with 4.1V instead of 4.5V for the correct overscan.

In case 2. you get 4.5V but your raster is to large from what I see and when I tried to duplicate here I couldnt. Only difference between you and I is the source and memory built and why I questioned it.

Ringing is usually a cable issue but thats a new thing to look at later. Check it on green only and see where the Momos sharpness is set to, again this is needed if you would check it. Does it do the same thing on a different display device like a TV or computer monitor?

Amplitude you can shut the red and blue off, what the green does the red and blue will do also.

Memory: I dont know, you havent verified the DVD settings on another display device when I had you normalize you said it was to tall and two skinny so you pulled it out again.

Something to check:
You use the video input first, not scaled and let it show on the screen, fit the H amplitude then let it show full 4:3 format, set display type 4:3 to check it and use the intro of the Avia disc. This will be full screen. Measure the image height to check format. Take your width and divide by 4 then times that by three thus (4:3) set the amplitude there and store for the video input for now. Just as a check set the display type as 16:9 and take a look. See what you get. Easier to do on a TV. Doug
Doug Baisey's Avatar Doug Baisey 05:12 PM 11-24-2004
Im sure this is something minor, dont let it get to you. When your on the video input normalize the amplitude again and build from there.

Your trying to get the page 10-11 voltages to come in spec for the lenses, this will tell you if your in the ball park or not. Go over both case 1 and 2, case 2 you will set for the 4:3 format VR5302 7.5V also.

If you come into spec leave it there. When you go to 720P it will use the global setting and you can correct the amplitude for that signal but dont move the pots again. 720P will need more electronic amplitude most likely.

Turkey prep time, three 30 pounders, Ill be gone tomorrow. Happy Thanksgiving!
garyfritz's Avatar garyfritz 10:27 PM 11-26-2004
OK, I see what you mean about the 10-11 procedure. Case 1 and 2 are two different ways of setting the same thing, but should produce the same results on the other part. I.e. set to 13% overscan and you should have 4.5V, or set to 4.5V and you should have 13% overscan. That makes sense.

But at 13% overscan I had 4.13V. I dunno what would cause that or how you'd fix it but apparently something is off. Maybe that 4:3 check you're describing, but I don't see anything there that would bring it into spec any more than what I've done before. It will probably be several days before I can get to that.

What kind of relationship would you expect on 720p RGB? Same 13% / 4.5V, or something different? My overscan is different on video vs. 720p.

Three 30lb turkeys, holy smokes. You must feed an army!
garyfritz's Avatar garyfritz 11:29 PM 12-05-2004
Hey Doug, are you still watching this neverending thread? I'm realizing one of my problems is that my back rasters are brighter than a "black" video signal. That is, when I have a grayscale adjusted so the dark end goes black, the raster is still lit up brighter than that black end.

Shouldn't the raster be as dim as a "black" signal? Otherwise you're left with a lit-up raster around the image. Even blanking doesn't get rid of that. And in really dark scenes the raster washes out the image.

If I turn the brightness down so the raster goes dark, the last couple bars of the grayscale disappear, and I lose lots of detail in dark scenes.

Is there some process I goofed, some pot I need to re-twiddle?
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