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post #91 of 102 Old 10-10-2013, 05:56 AM
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How so? Lower?

On another note, I just got a new set of VDC NOS LCP09's and one of the red tubes I installed needs a very high G2 of 72 and for some odd reason I had to lower brightness to 4 !!!

What might be the issue?

Athanasios
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post #92 of 102 Old 10-10-2013, 07:06 AM
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Hi Athanasios,

It's been a while. Having the G-2 set that high might mean the brightness has to be set that low. Why does the G-2 have to be so high? Unless there is something wrong it shouldn't be like that. What happens when you set the brightness to 50 and you lower the G-2?

Scott
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post #93 of 102 Old 10-10-2013, 08:24 AM
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If the G2 is lower then i get a greenish tint even if i set the drive higher. I think the tube might be bad,

Mac told me the potential between the cathode and G1 might be out of balance. He told me to try to run a full white field
at 100 contrast and 100 bright with the other tubes off for an hour or two to see if it helps.


At 50 I have elevated blacks . on my other long bow I have bright at 30. I have always had to go to low bright levels for these long bows.
Maybe its the way they handle G2 in the software?

nashou
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post #94 of 102 Old 10-10-2013, 09:22 AM
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See if the tube will cut-off. Set Brightness and Contrast to 50 and with no input or a black field input see if the tube will cut-off by lowering the G-2. If it still glows with G-2 set very low then the tube might have secondary emissions. A CRT rejuvenator can usually fix that.

Scott
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post #95 of 102 Old 10-10-2013, 03:15 PM
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Quote:
Originally Posted by tse View Post

See if the tube will cut-off. Set Brightness and Contrast to 50 and with no input or a black field input see if the tube will cut-off by lowering the G-2.
If it still glows with G-2 set very low then the tube might have secondary emissions. A CRT rejuvenator can usually fix that.

Scott

Ok set C and B to 50 and the red did cut off at 68 but, when using Tim Martins method for setting greyscale or when using my Calibration equipment I have to
jack G2 up higher than my other red tube. So using the grey scale by eye method red ended up at 76 G2 and 28 Drive. To me that seems high
but it looks ok.


Would running the G2 for red that high damage the HVPS at all?

Oh and let me disclose, I am using this in my Blend. I did swap out the red for blue location on this marquee but also swapped the G2 wire in the HVPS connector on the back of the power supply
chamber. So right from the HVPS i switched the red and Blue G2 wires. they go to the correct tube, I did have an issue at first where I had no G2 because the blade of the connector was bent as to not make contact with the
HVPS blade connector. So let me ask, would a weak contact make for me having to raise G2 on a tube? It might be that....

Athanasios
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post #96 of 102 Old 10-11-2013, 04:39 PM
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Quote:
Originally Posted by nashou66 View Post

Ok set C and B to 50 and the red did cut off at 68 but, when using Tim Martins method for setting greyscale or when using my Calibration equipment I have to
jack G2 up higher than my other red tube. So using the grey scale by eye method red ended up at 76 G2 and 28 Drive. To me that seems high
but it looks ok.


Would running the G2 for red that high damage the HVPS at all?

Oh and let me disclose, I am using this in my Blend. I did swap out the red for blue location on this marquee but also swapped the G2 wire in the HVPS connector on the back of the power supply
chamber. So right from the HVPS i switched the red and Blue G2 wires. they go to the correct tube, I did have an issue at first where I had no G2 because the blade of the connector was bent as to not make contact with the
HVPS blade connector. So let me ask, would a weak contact make for me having to raise G2 on a tube? It might be that....

Athanasios

Running the G-2 higher is actually easier on the circuit than when running lower. It is a shunt regulator so the lower the output the more current and power dissipation there is in the circuit.

A bad connection will usually connect then partially connect so the result will often be a flicker or nothing at all. It won't continuously drop the same amount of voltage.

The adjustments were designed to accommodate all the tolerances of the tubes. They can vary quite a bit so there needs to be a wide range. Don't worry too much if some tubes need a higher or lower setting. The projector was designed for that.

Scott
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post #97 of 102 Old 10-11-2013, 05:29 PM
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Thanks Scott, so running a higher G2 is easier on the G2 circuit in the HVPS and would that also ,ean I'd need a lower Contrast then? And would a slightly higher G2 increase blooming or is that totally a contrast issue?


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post #98 of 102 Old 10-11-2013, 09:26 PM
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Just re did the set up by eye for the blend. I must say it looks better than when I use calibration equipment!!! So the new settings are much better Used 50 and 50 to start my set up but am viewing
video at 33 and 64.

Now I will use my Calibration equipment to see where i ended up by eye and calibrate one display and see how it looks. Then I'll do the other.


Thanks Scott for the info.
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post #99 of 102 Old 10-13-2013, 08:23 AM
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Quote:
Originally Posted by nashou66 View Post

Thanks Scott, so running a higher G2 is easier on the G2 circuit in the HVPS and would that also ,ean I'd need a lower Contrast then? And would a slightly higher G2 increase blooming or is that totally a contrast issue?


Athnaasios

Higher G-2 is easier on the HVPS. G-2 and brightness are offset adjustments. That means that all the video is shifted up or down. Black, gray, and white are all effected together by the same amount. Contrast is a gain adjustment. The black is not effected at all, it doesn't change. Gray is effected somewhat but less than white. White is effected the most. Blooming is entirely a contrast thing. This is how the projector is supposed to work. I recommend setting the projector up with the video going directly to the projector. Don't do any video processing until the set-up is right then do the processing.

Scott
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post #100 of 102 Old 10-13-2013, 06:40 PM
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Quote:
Originally Posted by tse View Post

Higher G-2 is easier on the HVPS. G-2 and brightness are offset adjustments. That means that all the video is shifted up or down. Black, gray, and white are all effected together by the same amount. Contrast is a gain adjustment. The black is not effected at all, it doesn't change. Gray is effected somewhat but less than white. White is effected the most. Blooming is entirely a contrast thing. This is how the projector is supposed to work. I recommend setting the projector up with the video going directly to the projector. Don't do any video processing until the set-up is right then do the processing.

Scott

Thanks again Scott. That is the one weird thing tho with these Marquee's raising contrast affects blacks more than I like, for every two numeric values of contrast I have to lower Brightness one .

Also with these long bows the Calibration is a bitch!1 I do have a radiance in the chain but have it set to default and use its reference patterns for greyscale not using any of its
processing Red drive and blue drive really alter the low end quite a bit. A few clicks of red drive on 80 IRE makes a noticeable change in 30 ire . I wonder if
it the peking circuit of the vims or maybe the LongBow Software works the Color balance controls differently. I did remove the stock 8 inch tubes with new 9 inch tubes.

But I have calibrated other Marquee's and have not had the same behavior . I remember when I first got these instead of a blue Bump in the middle I had a blue dip .

I know I have gotten a nice flat calibration on my old 8000 with no processor, just a slight bump in blue on the mids.

But i will try a calibration of 20 and 80 using only my Oppo. I will have to set up a new memory for it. then hook up the radiance and the blend scaler to see how much they alter the oppo only calibration.


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post #101 of 102 Old 11-16-2013, 07:56 AM
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I not only do better filtering, but I also decouple all of the data and control lines form the processor and other sections of the PJ. That greatly lowers noise in the low range and brings the low end out better.

pNEg

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post #102 of 102 Old 04-17-2016, 08:12 PM
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I realize this topic has been dead for over two years.

That's OK.

I have one of (maybe two) full sets of the HR tubes made for the 9500HR, the big brother of the 8500HR.

No 9500HR was ever actually built but Tse did evaluate the tubes. They are proportionally superior to the 8" tubes, just as you would expect. Same spot size, more tube surface area to play with.

I bought this evaluation set from VDC for what I consider to be a very fair price. They are in LC chamber assemblies.

I have chosen to try to absolutely maximize their potential performance by using them in conjunction with the superbly sharp focus yokes found in a Barco 909/Cine 9. Those yokes require positioning on the tube neck that is far away from where the regular stock Thomson focus yoke would be, which is requiring me to at least attempt to modify the shorter Barco deflection yokes to run in a Marquee. Which by itself is a bit of a challenge, as I'm having to totally rework all the wiring on the deflection yoke and then have to analyze the resonant circuit values of the HDM and probably will have to modify the HDM and VDM to restore resonance to the deflection circuits.

I have (briefly) run the HR tubes with the regular Thomson magnetic stack and yes, they are sharp indeed. But I think I can make them sharper yet.

However they don't even have dag ground leads so I didn't run them for long at all. You would be stunned to find out how much voltage builds up on the ungrounded CRT bell and how quickly it builds up without ground straps! Enough to draw a 1/8" arc when shorting it to ground, in five seconds of operation.


To add to the madness, I just bought, from a surplus reseller, 13 of the "new" Tse designed neck cards, new in the boxes, still in anti-stat bags with unbroken seal stickers. They're the "retrofit" version that can be mixed and matched with the legacy cards.

The goal: If not 4K via HTPC, then at least find out what the limits are with the HR tubes and better magnetics. I predict that the GT17 lenses will reach their 12 line pairs/millimeter resolution limit at a resolution of about 3048x1714 pixels assuming that the pixels are "square", with 1000 pixels measuring the same length on the CRT face whether measured horizontally or vertically. This is a 16x9 aspect ratio raster.

In full frame, the lens resolution limit would be equivalent to 3048x2438, call it 3000x2400, near enough.
This assumes a 5" wide raster, which doesn't even come close to being a maximized raster. A 9" tube's raster
can be stretched to almost 6" wide before getting into edge of glass distortion. So...actually with rasters pushed to the ultimate limits, the lenses would permit a resolution of up to 3658x2743 (4:3) or 3658x2047 in 16:9.

Consumer 4K is 3840x1920 so from an optical perspective, we're within spitting distance of 4K, and allegedly the later Elcan manufactured HD10L lenses are "significantly sharper" than any lenses made by 3M/USPL.
So maybe they're 4K capable lenses.

I'm not going to bore you to tears with further detailed mathematical analysis of tube resolution, but I do make note of the fact that around the time Scott was doing the 8500HR evaluation and posting about it, I was able to duplicate his 2048x2048 resolution results using a green 180DMB (Or maybe it was a P16LNN, honestly I can't remember which) tube with the first "frankenyoke", the KF2211, on my Marquee 8000 testbed chassis. Though I could not resolve the pattern on the screen due to the severe limitations of the HD-8B lens, the full pattern was quite sharp on the CRT face. The improvement vs. the stock Thomson focus yoke was sufficiently dramatic that if the improvements to be made using the Barco focus yoke are comparable to that old experiment's results,
then 4K will indeed be close enough to be worth fighting for. However of course there will be bandwidth limitations that may keep true 4K forever out of reach.

That's OK, because I'll settle for 3K, which I judge to be VERY possible. 3K at 72 Hz, no less. That'll fit in 258 MHz of video bandwidth.

Come to think of it, I'm kind of confused how the neck card on my 8000 test bed was able to deliver 2048x2048 with good definition. I know it wasn't a modified card. Maybe the refresh rate was low. I'd have to power up the same signal generator and check that pattern's parameters to get that answer. (I can do that. I used a Sencore CM2125 and today I still have one of those.)
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