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stridsvognen
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| Posted: Thu Apr 26, 2012 7:44 pm Post subject: |
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I just made a 20 point grayscale measurement, and there you see the 5% IRE, who tells more than all the rest.
just to see that they are inside the scale is great. I'm sure that 1 hour of fiddling with this setting will get it almost perfect.
This was not possible with the mod.. 5% gamma was way to low, and not possible to push it up.
ill prefer as perfect black as possible before start adding external gamma correction.
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Thu Apr 26, 2012 8:53 pm Post subject: |
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well this is one of the problems with a machine that was designed for commercial applications and not reference video. Obviously Christy Digital could have done a better job than the three 1.5Mohm resistors.
I'd like to hear what Craig has to say, I'm sure he's calibrated machines both with and without this particular tech bulletin.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Thu Apr 26, 2012 9:45 pm Post subject: |
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| draganm wrote: | well this is one of the problems with a machine that was designed for commercial applications and not reference video. Obviously Christy Digital could have done a better job than the three 1.5Mohm resistors.
I'd like to hear what Craig has to say, I'm sure he's calibrated machines both with and without this particular tech bulletin. |
I will tell you drags my two longbows do not show any elevated black level with the mods. It Might be his set up I think.
I keep Brightness at 47 on my longbows using the Lumagens Test patterns. I think Kurts are set too high with the mods.
Ok Kurt this is how I set up the G2 for the marquee.
But first a little back ground info:
The Green Drive does not adjust as the same rate as the red and blue. It is about 20% of those two colors.
So set green Drive at about 90.
I found Blue Drive affects the Low end of the Blue much more than Red Drive affect the low end of the red.
So adjustments made to blue G2 should not be as aggressive as adjustments to red or green G2 adjustments the Blue Drive will make larger changes to the low end that the Red and especially the green drive will to their respective low ends.
This is why it make's it a slight challenge to get all three colors to come out of black at the same time.
So this is how I set G2's
First set the drive for Red to about 30 -35
Set Blue to about 45-50
Set Green to 90
Set Brightness and Contrast to 50.
Now put up the 5% or lower( I use the 1% from the AVS HD disc) IRE field from and external source.
Start with Green and lower or raise G2 till you see the raster or the 1% or 5% field just light up
if using the 1% field leave it there, if using a 5% field look at the raster and lower G2 till the raster is gone.
Do the same for all colors.
Put up a stair step pattern of the the source and see how the greyscale looks it might be off.
here you can use Tims method for greyscale on his site, skip the beginning parts as you have done that with my method
and go to the stair step patter adjustments. This will get you fairly close by eye.
Now use 30 and 80 % white patterns form your source and adjust those. You may have to defocus blue( not sure if you did or not but it usually has to be done for correct greyscale) Now make sure here you do not adjust green G2.
Now double check the Coming out of black if all looks good. I bet Blue comes out first.
This is normal from what I found on My marquee's. You might still want to lower Blue G2 and then go back and re adjust Greyscale at 30 and 80 now not touching Blue G2. And only adjust green G2 in small amounts. go back and check coming out of black again looking into tubes. It doesn't have to be perfectly the same but should be closer. The on Screen coming out of black will look better.
You may have to go back and forth a few times. it takes time.
Also you may have to then lower Brightness a few clicks. mine ended up at about 47. I I raised my Contrast to 70 through out this process so this also affects Brightness levels, why i lowered mine to 47. it still came out of black to soon so using the VP with a negative Luma value at 0 fixed my issue with out losing shadow detail. its just the nature of CRT.
Athanasios
_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
One Smart Dog!!!
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Marquee Modifications and Performance Enhancement
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Thu Apr 26, 2012 10:30 pm Post subject: |
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Nash I've done this now half dozen times and it's definitely makes the Black levels much, much harder to set. Like MP said it really jacks up the Black pedestal.
Does it make it impossible to adjust, no, but it makes it much harder. As with the back porches, 60HZ judder, full gamma control, you can add this one to the list of "Why you need a good VP with a CRT projector". Or at least with a Marquee.
A better solution here is possible I'm sure, but if it was easy the Christy Engineers would have done it. After the Cree FET problems I'm not willing to gamble a VIM on it.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Thu Apr 26, 2012 10:56 pm Post subject: |
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Like I said, I really never noticed any difference on the PJ's I have that have the mod Vs the ones that dont. I set the G2's the same way from my M8000 to my LongBows. Always notice the same behaviors( not negative or positive Just the same). maybe its in the chips associated in the design. I wonder if changing out the TLO71 with abetter Chip like an OPA 627 or TLE 2071 etc would make the mod more consistent?
Athanasios
_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
One Smart Dog!!!
Marquee High Performance Bellows now shipping!!
Marquee Modifications and Performance Enhancement
Marquee C-element and Bellow removal
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ronaldus
Joined: 25 Dec 2010
Posts: 183
Location: france
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| Posted: Fri Apr 27, 2012 11:30 am Post subject: |
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For Nashou,
Why does this SD5401 be a fast switching one is it also used for the overlay menus? If thats the case then my theory with the relay doesn't work off course. Good that you mention that.
For MP,
Thanks for the Idea with the pot. I'll have a look into that. and I have used 1.2M instead of the 1.5M. HK-Steve told me to do so but now you're talking about 2.2M It could also be a typo from Steve in his mail to me.
By the way I always did the "calibration" by eye with the internal test patterns. I will do a real setup when the projector on the ceiling on its final position.
Thats it for the moment.
Ron
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Fri Apr 27, 2012 12:31 pm Post subject: |
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| ronaldus wrote: | For Nashou,
Why does this SD5401 be a fast switching one is it also used for the overlay menus? If thats the case then my theory with the relay doesn't work off course. Good that you mention that.
For MP,
Thanks for the Idea with the pot. I'll have a look into that. and I have used 1.2M instead of the 1.5M. HK-Steve told me to do so but now you're talking about 2.2M It could also be a typo from Steve in his mail to me.
By the way I always did the "calibration" by eye with the internal test patterns. I will do a real setup when the projector on the ceiling on its final position.
Thats it for the moment.
Ron |
The internal test pattern is generated from two different sources. One is RGB from the control board directly into U16. The other is the onscreen menus (contrast, brightness, etc). That's injected directly into the SD5401 (B/W) also from the control boards internal generator. Replacing the SD5401 will not be easy because it not only switch from test pattern to source, it's also a high speed switch for the clamp pulse (U15). There are four switches in each SD5401 for each of the three channels. Tho switches are used for the video select, and two for the two clamping (pedestal) circuits.
So it may make more sense to leave the SD5401 alone, and simply deal with the problem at hand, and that would be a better solution for the best pedestal setting. And since the three resistors would be the only place you'll need to look at, then that should make and keep things quite simple.
When I get time, I'll modify one of my 02 VIM's that I have here, and post some pictures of what I've arrived at. The pot should be the best fix for this, because it would allow you to literally dial the line out of the image, and at the same time allow for a more precise adjustment for best pedestal level with the VIM installed and the all things in operation.
There is also another fix for this, that I done directly to the control board. But that's a different mod altogether, and for those who would not want to do the VIM change themselves, at least what I would be recommending, I could check with Tim and see if he could do both VIM and Control changes for you.
the goal would be to maintain as perfect pedestal as possibly along the entire video chain. And the more success in doing so would create the best overall image. Especially with HDTV signals, because the converted Digital Component HDTV source signal works best in the analog world when the black reference levels are not being clipped, elevated or compressed in the video chain.
Look at my screenshot on AVS. Look very closely at the defined darkness in the far backgrounds, and the clarity of the levels of black in the scenes. Something as simple as improved and more precise pedestals make for improved and better Ansi Contrast Ratio on CRT.
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stridsvognen
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| Posted: Fri Apr 27, 2012 12:57 pm Post subject: |
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Mike.
Maybe a stupid question, but i'm just thinking loud here. (I have no idea how its working)
Would it be possible to turn off the internal generator on the control board, or turn off the signal out of the generator, before the VIM.? Maybe something like a small switch on the back panel. so its possible to activate when needed.?
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Fri Apr 27, 2012 1:22 pm Post subject: |
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| stridsvognen wrote: | Mike.
Maybe a stupid question, but i'm just thinking loud here. (I have no idea how its working)
Would it be possible to turn off the internal generator on the control board, or turn off the signal out of the generator, before the VIM.? Maybe something like a small switch on the back panel. so its possible to activate when needed.? |
No, that's not a stupid question. A good one really. And it may be best to use a relay (for the sake of not running wires from the circuit to the switch on the VIM plate).
I'm thinking to put the switch or relay between pins 1 - 4 of each of the SD5401 switches (check this on the diagram).
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stridsvognen
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| Posted: Fri Apr 27, 2012 1:33 pm Post subject: |
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| mp20748 wrote: | | stridsvognen wrote: | Mike.
Maybe a stupid question, but i'm just thinking loud here. (I have no idea how its working)
Would it be possible to turn off the internal generator on the control board, or turn off the signal out of the generator, before the VIM.? Maybe something like a small switch on the back panel. so its possible to activate when needed.? |
No, that's not a stupid question. A good one really. And it may be best to use a relay (for the sake of not running wires from the circuit to the switch on the VIM plate).
I'm thinking to put the switch or relay between pins 1 - 4 of each of the SD5401 switches (check this on the diagram). |
Thanks, then ill continue thinking loud.. 
Next.. there is a mute function, and i doubt anyone using the audio, don't know how its working, but if its some sort of output to a relay, could that output be used to control the on off for the generator relay. 
Don't have any diagram... And if i had i'm not sure ill know where to look..
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Fri Apr 27, 2012 1:49 pm Post subject: |
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Keep thinking out load...you've made me say to myself; hmm.. why didn't I think of that.
Anyway, the MUTE control, I could not find. But while checking for it, I did find a way to avoid the POT in my idea, and use the "Volume" on the remote to adjust the pedestal level.
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stridsvognen
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| Posted: Fri Apr 27, 2012 2:03 pm Post subject: |
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| mp20748 wrote: | Keep thinking out load...you've made me say to myself; hmm.. why didn't I think of that.
Anyway, the MUTE control, I could not find. But while checking for it, I did find a way to avoid the POT in my idea, and use the "Volume" on the remote to adjust the pedestal level. |
Ohh now my head is all empty.. 
Ohh no wait  would it not be the best option to just turn the generator off, so its not connected to the video signal.. maybe meaningless but there must be coming some noise out of that thing.. And do you know if adjusting the pedestal level will provide some headroom or slip between the signal from the generator, and the video level. or will it always be some sort of balance between those 2 levels.?
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Fri Apr 27, 2012 2:24 pm Post subject: |
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| stridsvognen wrote: | | would it not be the best option to just turn the generator off, so its not connected to the video signal.. |
Yes, that would be the best option.
| Quote: | | maybe meaningless but there must be coming some noise out of that thing.. |
Yep.. a source of noise for sure.
| Quote: | | And do you know if adjusting the pedestal level will provide some headroom or slip between the signal from the generator, and the video level. or will it always be some sort of balance between those 2 levels.? |
There is or would be a difference between the two. actually, after going the external switch route, you may notice a difference in the image. Not sure, but I'm thinking that should happen.
The goal the designers had for the internal pattern has changed from what we'll be needing it for in HT. Because it's not so critical for us in alignment and calibrations. We use external sources, with only the internal step pattern being used for a reference only. So a more precise pedestal adjustment would allow for best headroom.
You seem to want to go the absolute best performance route, and I think you're on the right path. proper pedestals is one means of getting a better overall image, but noise is also another very important thing to look at, because you would be surprised at how much low end is being lost due to the amount of hash (high frequency crap) noise getting into the video chain.
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stridsvognen
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| Posted: Fri Apr 27, 2012 2:32 pm Post subject: |
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Mike.
Is there some easy way to pull the plug, then i could give it a try.? Some resistor that could be removed, prefer something that can be easy reversed for a start.
Maybe we could fit my homemade hi tec input selector in there somewhere.. 
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ronaldus
Joined: 25 Dec 2010
Posts: 183
Location: france
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| Posted: Fri Apr 27, 2012 2:47 pm Post subject: |
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Hi again,
It's getting and interesting discussion here!
I don't think we can put a relay there because as Nashou said those switches are used for the on-screen menus as well.
We could put a switch over pin 22 PC3 and 22 PA3 so that we block the internal video signals but it will also disable the overlay menus.
Cheers,
Ron.
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Fri Apr 27, 2012 2:57 pm Post subject: |
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| stridsvognen wrote: | Mike.
Is there some easy way to pull the plug, then i could give it a try.? Some resistor that could be removed, prefer something that can be easy reversed for a start.
Maybe we could fit my homemade hi tec input selector in there somewhere.. |
You would have to lift pin "1" on each of the SD5401 IC's to separate the video section from the clamp IC. You could do that and see what happens if you were to put a switch at the point we had discussed, and see what would happen when you switch the generator out of the circuit.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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stridsvognen
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| Posted: Fri Apr 27, 2012 3:28 pm Post subject: |
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| mp20748 wrote: | | stridsvognen wrote: | Mike.
Is there some easy way to pull the plug, then i could give it a try.? Some resistor that could be removed, prefer something that can be easy reversed for a start.
Maybe we could fit my homemade hi tec input selector in there somewhere.. |
You would have to lift pin "1" on each of the SD5401 IC's to separate the video section from the clamp IC. You could do that and see what happens if you were to put a switch at the point we had discussed, and see what would happen when you switch the generator out of the circuit. |
I lifted the pins, and thats not the way to go.. now the image is very bright, and when pressing # you get some bright distorted grid up, until you come back to the bright image.
Last edited by stridsvognen on Fri Apr 27, 2012 3:39 pm; edited 1 time in total
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Fri Apr 27, 2012 3:47 pm Post subject: |
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Guys
What if you select "OSD OFF" in preferences; would the generator be shut off? To get the OSD for a moment one just hits Contrast Recall, and you get the slider when needed.
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