Film-Tech Forum ARCHIVE: Barco Zoom Motor Problem

This is topic Barco Zoom Motor Problem in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Jay Glaus (Member # 6011) on 03-19-2013, 11:11 PM:

Hi all,
So we got our Barco 23B set up at the drive in. Fired it up yesterday during the day, then were going to get everything calibrated and aligned tonight when it was dark. We hit the screen... and the lot, and the trees, and the sky. Couldn't get the lens to zoom in or out to fit our screen. We ran the machine through a self test, and the zoom motor failed. Took the lens out, checked connections, re did lens files, re seated lens, nothing. You can see the board blinking in there when you hit the zoom buttons, so it knew we were hitting it, but the motor wouldn't budge. Called ACE, and they said it was the motor on the lens, which is what our tech thought who was installing. Apparently, the lens came with a dead or defective zoom motor.
They are going to hopefully ship a new lens tomorrow, we'll have it Thursday, and be able to get everything set Thursday night. So we should be on for the weekend (hopefully). I'm not betting the farm but I think we'll be ok.
Has anyone else had this problem? Is it common or were we just lucky?
The picture is huge, we have a 40 x 80 screen to begin with, and it's WAY beyond that. If it just curved around the sides of the field you'd have drive-in IMAX. Maybe I'm on to something here...
Jay

Posted by Brad Miller (Member # 2) on 03-19-2013, 11:17 PM:

You can adjust the lens manually to get on screen, ya know. Your tech should've known that and gotten you going. The lens could then be replaced when the replacement comes in.

Posted by Jay Glaus (Member # 6011) on 03-19-2013, 11:24 PM:

Really? How's that work, Brad? Is it something internal or right out in the open? I'm assuming it wouldn't be something I could do myself. I always planned to go and take the course to become a tech, just never made it there yet.

Posted by Brad Miller (Member # 2) on 03-20-2013, 02:01 AM:

Remove the front skin. Look in the center of the little square lens motors. Insert tool. Turn.

Posted by Tim Sherman (Member # 569) on 03-20-2013, 02:09 AM:

That is the focus located under the front skin. Zoom on the B-series is on the lens itself. On the C-series both zoom and focus are on the lens

Posted by Brad Miller (Member # 2) on 03-20-2013, 02:43 AM:

Tim is correct. I was thinking about focus and V/H offset under the skin. Regardless, it can be done manually.

Posted by Jay Glaus (Member # 6011) on 03-20-2013, 07:07 AM:

Thanks guys, hopefully the other lens gets here in time, if not though, we'll have to give that a try.

Posted by Steve Guttag (Member # 268) on 03-20-2013, 08:41 AM:

The lens was definitely properly homed...right? That is, the correct lens brand/model was designated?

I've never had this type of failure, myself but obviously, it could happen. Note, in addition to the lens motor, one would need to check the wiring from the backplane to the motor (There are a couple of connectors there...one near the lens and one to the backplane. Then there is the CinemaController itself...reseating it or possibly replacing it.

But here is what caught my eye. You have a 40x80 screen and you are trying to light it with a DP2K-23B...which tops out at about 21000 lumens. Just how bright (well...dark) are you hoping the picture to be? By my calculations...somewhere in the 4.2 or 4.3fL range unless you have some sort of super-bright paint on your tower (and if you do...please share what paint it is and relative "gain" it has.

And this supposes that you letterbox the Scope format and NOT fill the 2:1 ratio but leave it at 2.39. A DCI requirement. I believe 7.0 is the bottom a DI is "allowed" to be...even if they have to use the biggest projector to accomplish it (in your case as DP2K-32B).

Posted by Jay Glaus (Member # 6011) on 03-20-2013, 06:36 PM:

Steve,
Yeah, we checked all that, the lens model, and we had the front off and checked everything from the lens back, and everything seems to be functional but the lens motor itself. I'm really hoping we are correct. Barco overnighted us one today, we'll have it tomorrow.
And I don't know about the cropping, but as far as light, we were hitting about 9 footlamberts on the screen last night with the bulb perfectly aligned to the tee. We usually got between 7 or 8 with film, so it's nothing really noticeable though.
The light measurement was what I was waiting to see, because if it wasn't bright enough, we were going to ship it down to one of our smaller screens and get the 32 for the big screen. We didn't really have any moon, though, and a full moon can make a difference.
We don't really use any special paint, we just ask sherwin williams for the brightest white paint they have.
But, i'll keep everyone posted tomorrow if that fixes the problem!
Jay

Posted by Steve Guttag (Member # 268) on 03-20-2013, 07:39 PM:

If you are getting 9fL. Your screen gain is about 1.6. Presuming you have a piece of plate glass in the port.

Please note, that also presumes that you are running at 100% power and have not taken into account any aging of the lamp. If you, instead, drop your light to about 6.5fL (for Scope)...you'll have pretty consistent light throughout the lamp's life.

I'm real interested in this Sherwin Williams paint...its gain seems to be better than anticipated and could really affect light calculations.

Posted by Jay Glaus (Member # 6011) on 03-20-2013, 09:20 PM:

Yeah there's port glass. Thanks for the tip, I'll give that a try. That's one thing I was worried about, running it at max and it dimming out early. But that isn't a bad idea at 6.5 scope.
We've always found that the paint Sherwin Williams gives us is a brighter white that many others, and seems to give the picture a little extra gain. The only thing I've seen is sometimes is can give a little more gain to things you don't want, like the full moon or outside light. But it's still a trade off, and I guess that's why we have trees.

Posted by Barry Floyd (Member # 385) on 03-22-2013, 09:40 AM:

If he's using the same Sherwin Williams paint I am, which has been a drive-in staple for years, it's the Sherwin Williams A100 flat latex Exterior wall paint. I've got 59 foot screens and I'm using the 23B's with a 4200watt bulb. Picture is amazing.

Posted by Steve Guttag (Member # 268) on 03-22-2013, 11:10 AM:

Thanks Barry!

It appears that SW A100 has several different Flat versions...which did you use? Might you have a product number?

What sort of light are you getting with your 23Bs?

Posted by Jay Glaus (Member # 6011) on 03-22-2013, 12:42 PM:

Thought I'd give an update. Got the new lens in and working. Was on the screen for almost an hour last night. Getting ready for our first night open with digital!

Posted by Monte L Fullmer (Member # 2797) on 03-22-2013, 02:33 PM:

deleted

Posted by Barry Floyd (Member # 385) on 03-23-2013, 08:34 PM:

We're running the Ushio 4200 watt bulbs in our 23B's - and although ours screens are only 25 x 59, the picture is absolutely amazing. Very well pleased with the light output, especially on Screen 2 where the Barco replaced a Brenkert BX-60! Never heard from our installation guy what light meter reading he was getting. The picture was so completely different than what we had before, I really didn't think to ask.

As far as which version of Sherwin Williams A-100, I'll have to go dig through the garage at home to see what version we used. I honestly didn't know there was more than one version.

Posted by Dave Macaulay (Member # 813) on 03-24-2013, 08:11 AM:

If you look in "service" in communicator with the lamp on it will show the approximate Ft-L level on screen - assuming the installer set the CLO file correctly. You can check in file manager under CLO files to see the creation date of the file used, it should be the installation date.