CurtPalme.com Home Theater Forum

racerxnet · Joined: 20 Jun 2007 Posts: 362 Location: Illinois

Has anyone tried to mount the lenses from a 9" LC machine to the AC Marquee. Just wondering if anyone ever gave it some thought.

MAK.

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

It won't work. The C element is critical in the optical system. You won't get a properly focused image without it

There was an 8500LC but it was discontinued a number of years ago. It used the same lenses and C elements as a 9500LC but
obviously the casting that holds the CRT is different.

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

I think The VDC Marquee 8520's used new LC chambers those were made for the HD117 lenses, which dispite their short throw (about 1.1x) are great lenses, TSE showed 1080p well resolved in the 8500 HR experiment using such lenses. The downside is that there are no known colored C-elements for the HD117 lenses. Also there are two subversions HD117-12 for smaller screens, conservatively up to 1.5m, but later test showed they focus fine even at 2.5m wide screens! The HD-117-24 lenses are for larger screens indeed, more expensive, rather hard to find.
Curt parted out several machines a year ago or so, perhaps he still have some chambers from those?

Hunting for an old 8500LC chamber is also worth considering, since the HD-10 lenses are great quality lenses also, especially for 8" machines, in turn this setup would have longer than usual throw, also you need the expensive bellows and 9" colored C-elements.

There are other chambers used in Barco retro chassis those fit the Marquee 8" tubes, but those would mean too much mechanical work I think.

As for other 8" LC lenses: HD-18 is the general 8" LC lens, found in Sony G70 and NEC XG LC, these came usualy with colored C-elements (perhaps this could be paired with the VDC 8520 assembly?).

I had NEC a 9PG xtra (with HD-145s) before the XG 135LC (HD-18) and I have the feeling the HD-18 is not as sharp as the HD-145. There is an other lens called HD-134, which shares tthe same C-elemnt with the HD-18 and is considered a high resolution lens, you better to forget about it, because it is by far the rarest lens ever made, and is ridiculously expensive for that reason...

There are also the HD-214/215 lenses I think, found on Cine 8 Onyx for example, they are pure crap, the don't even have edge focus knobs, although they usualy came with colored C-elements.

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

Yes, I have a red tube assembly from an 8520 and the parts to attach an HD-144 lens to it. I haven't done it because that's not really anything I NEED. The mounting is different anyway.

I am sure, however, that 8" red and green C elements do exist, because as I recall, Barco used them on certain projectors.

But they're as rare as common sense in Washington, DC.

There are companies that could theoretically take clear plastic C elements and apply dichroic red or green filter coatings to them. If those companies know their business they'll be able to nail the exact filtering specs that would be desired.

I would suggest that the dichroic coating be applied on the lens-facing side of the C element so there is no possibility of a chemical interaction between the coating and the coolant.

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

Oh, there is a company that has been selling 8520 parts on ebay regularly for some time now. I've bought some parts from them. I can't recall their name or handle right now but if I come up with it I can post it here.

You might be able to get the parts from them to turn your 8500 into a sorta-8520. And if you end up with the tube assemblies but the tubes are roasted, you CAN extract the 180DMBs from their cooling housings with some careful effort. I've done it before. It was rather tedious but I got it done without damaging anything. Then the 180s can be swapped into the 8520 housings.