CurtPalme.com Home Theater Forum

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Yes, that is correct. Except that blending has you overlapping the image area between two projectors and using either blending software or blending hardware to handle the blending in the blend zones by modulating the contrast levels of both projectors in those areas.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Quick update, I've now got a JVC RS45 D-ILA projector and I have been comparing it to my Marquee in my theater.

The JVC is sharper, pixel for pixel, but I'd expect that out of any fixed pixel device.

Black levels are actually comparable.

The Marquee is not focusing optimally on all tubes across the whole screen. I've got other Marquees that focus better so there's
a repairable focus issue to be dealt with. But the best focusing areas on the tubes are really very much equal in real world sharpness to the JVC unit.

Once I got the color temperatures adjusted to be pretty much the same, and adjusted contrast to be in the same ranges, then the difference between the two projectors has become rather minor. I would actually say that the CRT image is more natural, and that's the truth, so far.

Next I shootout the JVC against my best G90. (Best tubes.) I expect it to have better focus performance than the Marquee,
so actually I expect it to beat the JVC by a reasonable margin.

Since I have really nothing to do over the next couple of days, I may do this this weekend.

pj-toso · Joined: 19 Mar 2015 Posts: 69 Location: Norway - Oppland

justin_f · Joined: 27 Nov 2010 Posts: 52 Location: Australia

have you had a thought about the age of the technology you are comparing?

i enjoy the smooth image i get from my cine 9. i am not defending crt or offended. the digital jvcs and sonys are nice units for sure.

I often goto home theater movie nights where friends have medium level projectors (epsons). these things are pure light cannons. after 15k (yes, 15k) hours the lcd panel devoped a blue tinge. it was very obvious.

this became an eye sore and the owner paid more than the original unit to upgrad. they bought the next model medium level epson. another light cannon. this time it was sharper. I was surprised at the quality. but it cost more than the original epson they replaced...

if these crts didnt command such a high price tag in the beginning, they would hve been common household names?

I think comparing crt to digital now falls down to service ability, repair ability and longevity... and if were only now comparing the top shelf digitals to a set made 13 years ago...?

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I am doing the comparisons just for the fun of it.

The RS45 is not a light cannon, it's rated for only 1300 lumens which coincidentally is what a G90's peak lumen rating is.

The RS has been recently calibrated by its former owner, who is a good friend of mine, so it should be pretty close to being
in calibration now.

I expect that 10 years from now I'll still have CRT projectors running strong, if I choose to stay with them, and at the same time,
the RS45 or any other digital projector will have pretty much irreversible age related degradation.

I could easily tell the digital projection industry how to make their products last longer but there's no point, they want to sell
new units every few years and they want their products to have a limited service life. Planned obsolescence.

How to do it? How to make a digital projector last longer?

Use non-bleaching, non-fading dichroic color filters (Metal film deposition, not organic.) Employ IR filtration to remove heating energy from the optical core, and make optical cores built without adhesives that become brittle or turn yellow or creep with age and heat. Hermetically sealed dry argon charged optical cores with a heat exchanger system that keeps them cool wiithout running external air through them. Not using materials that change their material properties due to exposure to the light and heat within the optical core.

pj-toso · Joined: 19 Mar 2015 Posts: 69 Location: Norway - Oppland

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Just to clarify... Epson projectors are low end, period. I service digital PJs and epson PJs are pure garbage. They don't last worth a damn, and usually are proned to display failure of some kind.

medium level projectors are like the Sony's and JVCs, good 1080p machines.

High end projectors are like digital projection, Barco, Christie, etc...

Epson, Optoma, BenQ, Acer, all total crap, anyone buying one should NOT expect a medium or top grade machine. You get what you pay for, and in the world of digital PJs, $2000 or less for a new PJ is crap. Period.

Also, Digi PJs (if you have the technical skill) are very serviceable. I've replaced polarizers, DMD chips, LCD panels, things like that require extreme patience and precise alignment, but I have done so with great success. I've also repaired ballasts, mainboards, and power supplies.

To me a digital is just as easy to service as a CRT PJ, if not easier.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I agree. If you know electronics repair (I do) then electronics is electronics, troubleshooting works the same way no matter what the device is. I've been doing it al lmy life and my last "real" job had me working as the chief technician/engineer for a small
shop that specialized in two way radio systems, but we did a lot more than just radios.

I have the attitude that you can't break anything I can't fix, or design anything I can't build.

What I can't do is design new electronics. I'm a technician, not an engineer.

Oh, I can design simple stuff, and I can design systems of existing products. I can modify stuff if I understand it well enough. But I'm no circuit level designer.

**AnalogRocks** · Posted: Sat Dec 24, 2016 6:49 pm Post subject:

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

So, do you by chance happen to have the service access codes for the JVC RS45? I want to look under the hood. Not adjust anything, just look at the adjustments.

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Okay so this is from the HD950/550 SM, but it may work with the RS45:

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I'm going to start prepping a case cover set for repainting. In the process of picking out one of my four sets for painting, I discovered
why Sony paints the top section in a grey textured paint: Because the part is too bumpy to look good in gloss!

It's going to take some filler and some time to make it worthy of a high gloss finish. But I can handle that.

Tuesday I get my reworked and repaired YA board and copied over Dallas chips back and then I'll be back up to three fully running G90s. The fourth one is short a YA board and I may or may not seek one out for it. Not this week, anyway.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I'm back up to three running G90s. One YA board got repaired and I had two new Dallas chips copied over.

Trivia: Three running G90s powered off one power strip with a 15A breaker WILL pop the breaker after several minutes of operation.

Three running G90s also generate a noticeable amount of heat.

I'm no stranger to equipment that generates a lot of heat. I have a pair of Krell KMA-160 monoblock power amps in my system
and they're pure Class A from input to output, and they draw about 7.5 amps each. They heat up the room very effectively.

Not surprisingly, three G90s seem to be about equal in their heat output as compared to the two Krell amps.

A home theater should be designed with a bit more air conditioning in that room than other rooms of the house of the same size.

It's interesting to compare these units side by side. I haven't done much, if anything, to them regarding their basic setup
since I got them. Raster size hasn't been changed. And at the same throw distance, one of them has a raster width
that is not a lot more than HALF of another unit. It was installed too far away on a slightly small screen. This caused premature tube wear and expanding the raster to a more normal size would show the wear quite clearly.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Tonight I saw one of my G90s sync up and display an image at 24 FPS. It flickered like a hand-cranked movie from the 20s but to my surprise, it displayed an image.

My experience with these G90s so far is that I have not YET gotten any Marquee to focus as sharply as a G90 across the ENTIRE raster when taken as a whole. I'm working on a fix for that for the Marquee, but it's not done yet.

A few things I've found in comparing Marquees to G90s:

Marquees have 45 convergence points, G90s have 25. Advantage: Marquee
Additionally, once center convergence is established, there are no convergence zones in a Marquee that can not be adjusted both vertically and horizontally. With the G90, there are some convergence zones that are limited to horizontal adjustments only as they're on the horizontal center line which is adjusted with geometry. Advantage Marquee again.

Marquees have five focus zones. G90s have, well, I sort of forgot to count but I know it's nine at least. But, I have been able to
get a G90 to have sharp focus in the center of each zone and have it visibly out in the area where zones meet. Not by a lot, but by enough to see it.

Marquee focus can be erratic and unpredictable. While it may focus in the center at a focus value of 60, the left side edge focus zone may require a value of 10 to achieve full sharpness and the right side zone may require it to be set to 100.

The G90 is much more reliable in this respect. Focus values don't change very much as you work your way across the screen.

While the Marquee has mechanical 2, 4, and 6 pole CPC magnets (flare, astig, and triangularity) and electronic astig, the G90 has no mechanical CPC magnets but features electronic 2, 4, and 6 pole adjustments which are extremely precise and make the Marquee
implementation of electronic astig seem rather crude in comparison.

Interestingly, the G90 features 4 pole (astig) adjustability at every zone focus point, but 2 pole (flare) and 6 pole (triangularity) adjustments are center point only on the G90, which strikes me as a missed opportunity on Sony's part because once they have
built the dynamic circuits that handle the 2 pole and 6 pole adjustments, making them work in a multi-point adjustment setup,
like how astig works in a G90, would have been pretty close to trivial to implement, and given still greater control over image
sharpness at every point on the screen. (6 pole, anyway. I'm not sure if having multi-point flare adjustments would be beneficial.)

With this new information in mind, I'll have to scope out the 6 pole signals to be sure but I THINK that they're static DC values
and if that is true then it restarts my idea of adding G90 CPC rings to a Marquee along with a custom built driver board which
is really nothing but a stack of small DC power supplies and some variable resistors.

This is also interesting in that the Marquee features TWO ways to adjust astig, via mechanical astig CPC rings and via electronic astig, but the G90 only offers one astig adjustment system.

Perhaps most interestingly, the G90's image qualities have a "Sony family feel" to them. It's hard to describe but after you've
worked with several models of Sony CRT projector you start to see it. The image is subtly different than if you were to see the
same thing on a Marquee. It's not a calibration issue. I don't know what it is but it has a definably "Sony" character to it.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Hit a snag in the project to replace another green tube: I found that I have not one, but TWO factory
mislabelled tubes. They're both indicated as green, made by Mikado. On testing it turns out that
they're BOTH red tubes.

This is not good. It means that I went from having just enough green tubes to being short.
And I have further increased my over-abundance of red tubes.

This will cause me to have to accept a lightly worn green tube, for now, that I had intended to replace
because I "knew" I had spares.

CIR Engineering · Posted: Fri Jan 13, 2017 1:40 am Post subject:

That really sucks.

I checked the green you sent me and it is green much to my relief... then I remembered that you had used this tube already Wink

craigr

km987654 · Posted: Fri Jan 13, 2017 2:34 am Post subject:

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Too old, and I got it second hand. (Actually, two of them. Same deal for both.)

There is another slight chance that they were labelled correctly. Because....Mikado used white labels for a time, rather than red, green, and blue labels. I've ONLY seen these mostly white labels on these two tubes. The Mikado logo is green on both of them.
I have not seen white labels for known red and known blue Mikado tubes.

The problem is that the company that used these tubes cut off most of the label, leaving only the part with the Mikado logo and the serial number intact. The part that actually gives the tube part number is long gone. So maybe they were using white/green labels for every tube regardless of color. I can't know at this time.

Anyway, I dug into my pile of spare tubes in flat boxes (six tubes per flat) and found a green that looks good. By good I mean,
I don't see ANY wear on it.

I have a number of greens with light wear on them that would certainly provide many hours of good quality viewing enjoyment, but I'm not putting those into a projector I'm putting a lot of time and effort into. The G90s deserve tubes that really have no visible wear.

Effective now I've got two prime condition G90s available. If I sell one then Curt WILL get his share. I made that agreement with him long ago. I don't put up for sale ads for working projectors but as long as he gets a cut of any ensuing sale, I can mention that I have some available in a post like this.