CurtPalme.com Home Theater Forum

[stefuel]

I think the title says it all but who's design stands out above the rest and why???
My main interest is,

Leaks
focus
adjustability
resitance to fungus

[cmjohnson]

Other factors to consider should be availability of parts such as the bellows.


I believe VDC has that answer covered for ALL LC types but when's the last time you found a source for Barco bellows?


AmPro's LC chamber system is bizarre. It even requires special prescription C elements. (in some models, at least.) I would rank
it LAST for your choices.

The Marquee LC assembly has the advantage of being easy to come by and bellows are of course available. But they have some
aluminum corrosion issues with the glycol. Painting the chambers with a good epoxy is recommended to try to avoid that. It's a good
choice but maybe not the BEST choice for your project.

I think the Sony (G90) and Barco LC chamber designs are both excellent, and the most mechanically advanced of any of them. And
with G90s starting to get parted out, I'd be looking for a set of G90 LC chambers. I think you can still get the bellows from Sony,
or if not, VDC probably has them.


CJ

[Mark_A_W]

G90.

Best flapping mech.

[zGman]

G90 and (G70) bellows are metal, with a separate expansion chamber.
The Sony flapping system is very smooth and easy to use. But the G90
housings are enormous, and are too tall to fit in a Marquee chassis....

Barco housings are lightweight and the bellows do not seep, which
is good because they are permanently glued in. The flapping requires
a little caution to not strip the cams and approximately three hands to operate.
I like the Barco because the entire front section of the tube is bathed in coolant,
the glue is only on the sides.

G

[zGman]

Another thing is that the Barco 9" LC housings do not bolt directly to the lenses,
so if you are considering using them for a project you will need also the chassis
& frames, or heck just get the whole PJ......!

G

[Mark_A_W]

[zGman]

Mark - I just went and re-checked - I have bare, clean G90 housings and
G70 housings here. ( No, they are not for sale. Ok, well maybe the g70 ones...!)

The bellows, which can only be seen when they are dis-assembled, are METAL .

You can also see the seam where they are glued to the outer housings. Nice stuff.

The rubber that you see on the top is just the separate expansion chamber.

G

[Mark_A_W]

Ok, I stand corrected.

My memory is really playing tricks on me, or we just never noticed.

[Nashou66]

Here is a pic of a G70 LC chamber retrofit for a marquee PJ.



nashou

[Mark_A_W]

I guess we just never noticed.

[zGman]

Hi Mark - they are nicely black anodized - I was pretty impressed when I saw it....
You actually have to tap it to realize it is metal....

Nice to see someone made that g70 LC conversion work - I had considered it
but the tubes are bigger and then the barco 8" LC housings came along
and that was a lot easier...

Cheers,
Galen

[km987654]

[stefuel]

I think that is a bit of mis-information as the "c-element" technically is a part of the lens and not the coupling.
I have standard red and green c-elements installed in my 4600HD which focus just as good as the factory clears that came with it. If the "prescription" were in fact different, they would not work with the HD-10 lens they were designed to work with. The only way it could be true was if special lenses were built just for AmPro. I doubt that.

[km987654]

[CIR Engineering]

The G70 and G90 bellows are absolutely made of metal and I echo the sentiments and comets already stated. To perform flapping there is a continuously variable adjustment for the vertical and horizontal that is spun with a box or socket wrench from the front or through the bottom (easily accessible). The flapping adjustments are by far the easiest and most precise of any projector in existence and the neutral center is marked on the bellows so you know where to start!

Furthermore, its funny because while retubing a G90 just two days ago I was once again thinking about how amazing the G90 rubber gaskets and expansion chamber is. I have seen exactly zero rubber parts from the G70 or G90 fail and they are all in pristine condition. I don't know what kind of rubber Sony used, but it seems to be indestructible. Sometimes when I separate an assembly I have to pull quite hard on the rubber gaskets and I am always squeamish that they might rip (after 12 years they sometimes stick to the metal parts during disassemble). Tearing any part has never happened and every time all the parts come apart perfectly with no damage.

To date I have only seen one G90 with one tube that had some sort of contamination in the glycol. The glycol was totally discolored and looked terrible when I dumped it. All other G70 and G90 tubes I have taken apart have had perfect glycol and I even have considered reusing it because it always looks new. I actually did reuse the glycol on my own green tube last year just to see what would happen and so far it is still perfect.

Also, the Sony G90 is about the easiest housing to remove a tube from. No digging out silicone or using clamps or hammers or whatever. No soaking in turps or gasoline. Just dump the coolant, remove the four screws that are easily accessible and never frozen (stainless steel), separate the components, and slide a razor blade between the tube face and hardware. There are even four small spacers that separate the tube from the housing to allow a razor to fit in with ease. Takes about 15 minutes to remove a tube from the housing (don't lose the spacers though as they are small).

Recap: excellent easy precise flapping, no fungus, perfect rubbers every time, easy to disassemble and remove old tubes.

Kind regards,
craigr

ps the G70 tubes are even easier to get out of the assembly than the G90 if you want 8"

[CIR Engineering]

Oh yeah one more thing, with the G90/70 the CElements are NEVER glued in. Four Allan screws, a rubber gasket, and two seconds later the CElement is removed every time.

craigr

[Spanky Ham]

I had slightly discolored glycol from the G70 I took apart. The other G70 and G90 look fine. The 909s are all over the place with some discolored and some perfectly clear. I recently had to move them and now they all share the same room. I hope a fight doesn't break out while I am gone.

[draganm]

i've been working on MArquee LC chambers for a couple of years now since they've become more available and I hate them. Thye're a complete Fred Flintstone garbage design and you don't get to just re-build them anymore. Mostly it's going to be a restoration with Epoxy paint, new screws, new bellows, digging, prying, potting .

[CIR Engineering]

[CIR Engineering]