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I may have been wrong. Now THAT'S a sharp neck card!

 
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cmjohnson




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


PostLink    Posted: Wed Apr 12, 2017 2:07 am    Post subject: I may have been wrong. Now THAT'S a sharp neck card! Reply with quote


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I just picked up yet another Marquee. I think this is my eighth one.

It's my newest one yet, a 9518LC with a 2007 build date.

It's from an F/A-18 TOFT simulator installation, complete with very clear image burn of the left or right
wing view, wing clearly visible, along with the missiles and bombs on the hardpoints.

First, while the nearly pentagonal wear is fairly severe, I noticed that it's very sharply defined, very clean wear,
and on closer examination I noted that the scan lines are actually burned in.

The only way you get individual scan lines in a raster burned in like that is if the projector is extremely stable
in the long term. Impressively so.

Then I started evaluating focus. And frankly had a hard time believing what I'm seeing. The sharpness of this
unit, even with well worn tubes, is absolutely EPIC. I haven't even attempted to rough in the setup other than just
do central convergence and it's so sharp you'd almost think it was a digital projector.

Given the date of manufacture, I figured that the newer 0340 type neck cards may be in it, which, in the opinion
of some people, have a reputation for being very sharp although they were never designed to match the bandwidth
of the classic 0338 and 0339 version cards.

I checked, and indeed it does have the 0340 type cards which were designed by our own friend and forum member,
screen name Tse. Whom I know personally.

I was always skeptical about the newer cards being sharper than the older ones. Even Tse does not seem to think
that this should be the case, and he designed them!

But, whatever, I am skeptical no more. The sharpness of the cards in this unit can not be denied, although I am
not able to explain WHY they are so sharp.

It may be something as simple as the newer cards simply being newer, with all newer components that have not aged
as much as with any of the classic cards, many of which are now 20 years old.

It is fair to note that the only electrical connection on the CRT that does not pass thru the neck cards is the anode connection,
so I suppose that there may be other parameters in play that make these neck cards so sharp. But I don't know that yet.

What I want to do for the sake of comparison is take a known good "legacy" neck card, one of the well regarded 0338 or 0339 cards, and replace the components that are most likely to have drifted with age and try to make the card perform like it was brand new, and then compare that to the newer 0340 cards.
.
I predict that overhauling the older card WILL help. But will it make the card as sharp as a newer 0340 card? I do not know that yet. I HOPE that it does. Because if it does, then there's another way to improve the sharpness of your Marquee.
Overhaul the neck cards to make them act like they're freshly built.


Of course I'm going to retube this projector. Hopefully the new tubes will retain the sharpness of the old ones, which
are very sharp but worn well past the point of being unwatchable.
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garyfritz




Joined: 08 Apr 2006
Posts: 12024
Location: Fort Collins, CO


PostLink    Posted: Wed Apr 12, 2017 2:14 am    Post subject: Re: I may have been wrong. Now THAT'S a sharp neck card! Reply with quote

cmjohnson wrote:
I just picked up yet another Marquee. I think this is my eighth one.

How many boxes of tubes do you have stacked up around there, CJ? I think you may have taken Nashou's "CRT Hoarder, err Collector" crown...

Burned-in scan lines, that IS impressive.
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cmjohnson




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


PostLink    Posted: Wed Apr 12, 2017 2:56 am    Post subject: Reply with quote

Well, the boxes on both sides of this storage unit contain (up to) six tubes per box.

But to be quite honest about it, a lot of these tubes are not good enough to sell as good.

I am extremely picky about what goes into a projector. My basic requirement is that the tube must be
virtually in new condition. That means zero visible wear or defects in a 16:9 maximized raster area.

I have some B stock tubes that MAY bring a little bit of money. If you can tolerate ONE small defect in an
otherwise perfect tube, I can offer incredible deals on some tubes like that.

But most of them will be heading to the recycler over time. People just don't want tubes that have very, very light wear
if the edges of that wear cross over the edges of the active raster area and that is exactly the case with a lot of these.

To give an idea, I have about a dozen brand new PT-22 green LCPs with P43 fast phosphor on the right side, along with I think
it's eight 8" P43 fast phosphor tubes as well. (Green) I know that I have not less than 18 perfect red LUGs in here. I have,
I think, not less than six each blue and green new condition LUGs, not counting those mounted in Marquee hardware.

I'm sure that between these and the tubes in my projectors I have over a hundred CRTs. I will get more over time but will
also weed out the less than excellent ones so I expect the total to shrink a bit.

Aside from two recent projector additions to my ever-growing overstock of projectors, every projector features zero visible wear
or brand new condition tubes.

I'll change out a tube for ANY visible wear.



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cmjohnson




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


PostLink    Posted: Wed Apr 12, 2017 3:45 am    Post subject: Reply with quote

I just had to drag out my Sencore CM-2125 monitor analyzer and hook it up to this projector, because it allows the generation of test patterns at resolutions up to 2048x2048, which is exactly what I set it to.

Photos to be posted tomorrow.

Flat out unbelievable. Even the fine text screen was fully resolved and sharp EVEN IN THE CORNERS. Granted, still no effort has been made to set up anything at all, it hasn't been properly pointed, tubes haven't been aimed, sheimpflug hasn't been touched, and all those are way off. But by simple adjustments to mechanical focus and some electronic focus tweaks, I got it so sharp at this high resolution that I can truly say that I don't believe I've ever this kind of sharpness out of a CRT projector myself before.

I think it may be even sharper than one of my G90s.

This unit will get some STUDY before I retube it. And the setup of its existing tubes will be carefully studied as well.
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thewolfman




Joined: 28 Mar 2011
Posts: 1311
Location: Sweden


PostLink    Posted: Thu Apr 13, 2017 12:27 am    Post subject: Reply with quote

I took the liberty to post the simulation in question, and have to say that is one cool adult Playstation there. Super Hornet, damn it! Very Happy

http://www.defenseindustrydaily.com/australia-to-buy-24-super-hornets-as-interim-gapfiller-to-jsf-02898/

img host
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cmjohnson




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


PostLink    Posted: Thu Apr 13, 2017 12:33 am    Post subject: Reply with quote

That's it. I've worked on those. And probably will again!

Given the time, the space, the money, and the inclination, I could replicate that from a functional perspective.

It uses 9 projectors for the rear cockpit, and 11 for the front.
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pj-toso




Joined: 19 Mar 2015
Posts: 69
Location: Norway - Oppland


PostLink    Posted: Fri Apr 14, 2017 3:28 pm    Post subject: Reply with quote

Damn. Thats one complex setup.
_________________
Disclaimer: My postings are subjective and not facts.
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gjaky




Joined: 05 Jun 2010
Posts: 2789
Location: Budapest, Hungary


PostLink    Posted: Fri Apr 14, 2017 4:14 pm    Post subject: Reply with quote

I still think the key in here is the way how the tube biased.
The new VDC neckboards are "brighter" than the classic boards, therefore it is usualy compensated through the G2 settings. by decreasing the G2 value in fact increases the G2 voltage, and the higher the G2 voltage is the tighter the beam will be (and dimmer of course). An extreme of this setup would be to set the brightness to 100% and adjust G2 for normalize black the levels. Note that both G90 and the 909 have biased at significantly higher Cathode voltage as well, which is (supposedly) compensated on the G2 side
But of course old PSU and stuff can also contribute to this.

_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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cmjohnson




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


PostLink    Posted: Fri Apr 14, 2017 7:19 pm    Post subject: Reply with quote

I have acquired the full tech data on both the LUG and LCP tube types
which may shed some light on this. Haven't had a chance to review
those docs yet.
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