Film-Tech Forum ARCHIVE: Barco projectors shaking

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Posted by Michal Matys (Member # 8614) on 05-12-2015, 06:10 AM:

Hi guys,

I wanted to ask if anyone of you have experience with shaking Barco projectors. You can see it on the subtitles, sometimes less sometimes more.

We have several units which have this issue, I have checked if there are any faulty fans or something, its not the issue. The exhaust fan is not the issue as well since we have it hang on the ceiling.

Anyone ever had those issues with Barco projectors?

Thanks in advance for your ideas.

Posted by Edgar Prass (Member # 7558) on 05-12-2015, 06:22 AM:

Our 20C is rock solid and it's standing in a frame, which hangs down from the ceiling. The frame allows it to move a bit, so it's not completely fixed to the building itself.
What's the direction of the shake? Horizontal? Vertical? Random?
And what's the model?

Posted by Dave Macaulay (Member # 813) on 05-12-2015, 08:32 AM:

This is a known issue with the "B" series projectors. Any structural vibration is picked up by the weak lens mount - I've seen this when trucks drive by a theatre or when anyone walks by the projector, even when patrons are moving around.
The fix is to set the projector pedestal on compliant mounts designed for the unit's weight: this makes them more prone to shaking if someone touches the projector or pedestal but eliminates the vibration from structure movement. On a solid concrete floor in a good rigid building they are dead steady, image shake shows up in wooden or less rigid buildings. The C and S projectors do not have this problem, so if it's not a B then look elsewhere.

Posted by Carsten Kurz (Member # 5396) on 05-12-2015, 02:22 PM:

Yep, Barcos lens vibration issues have been discussed a couple of times on this forum. There is a stabilizer retrofit kit from Barco. It doesn't solve the issue entirely, but for some projector/lens/throw combinations it seems to work.

- Carsten

Posted by Sam D. Chavez (Member # 1841) on 05-12-2015, 06:10 PM:

I have had experience where the base feet lock nuts were not tightened. It was not the first place I looked but it solved the problem.

Posted by Steve Guttag (Member # 268) on 05-12-2015, 09:44 PM:

I've found that the current B-series lens stabilizer fixes the problem as well as any other projector, at this point. The current one uses a linear bearing to effectively prevent any lateral shake or vertical shake as well as ensure that the focus can only move in/out without any rise/fall.

Now there was an earlier stabilizer that used a set of ball bearings that tried to press down on the top of the lens mount...that had varying degrees of success and it all depended on the down angle and the weight of the lens sticking out of the front. Generally, with Invision lenses, you are a gonner! They are quite heavy and stick way out of the front. The Minoltas never were as bad...they are much lighter and they don't really stick out that much on the B series.

Posted by Dave Macaulay (Member # 813) on 05-14-2015, 07:42 PM:

I haven't seen that kit. The lens mount should have had linear bearings from day one. The rooms we had big trouble with have InVision lenses, the compliant mounts worked there after the first Barco "fix" didn't.

Posted by Dave Macaulay (Member # 813) on 05-15-2015, 10:05 AM:

Here's the solution we found:

Posted by Carsten Kurz (Member # 5396) on 05-15-2015, 12:09 PM:

What's that - burnt waffles?

- Carsten

Posted by Dave Macaulay (Member # 813) on 05-15-2015, 12:50 PM:

I don't have the spec with me. We went to a vibration engineer and gave the system (projector + pedestal + server etc) weight. It is 3 layers of some specific rubber isolating pad material. I've used similar stuff under speaker cabinets but I think this is a different material.

Posted by Sam D. Chavez (Member # 1841) on 05-15-2015, 02:06 PM:

I believe Mason make a whole range of isolator pads. I've bought similar devices on McMaster Carr.

Pity a $50,000 projector that shakes that bad without resorting to burnt waffles.

Posted by Steve Guttag (Member # 268) on 05-15-2015, 02:12 PM:

The Barco part number for the current "kit" is R5905599. Watch out, Barco likes to try and charge for it. However, it is worth making your case that the problem is caused by faulty design to get it covered by warranty.

Posted by Marin Zorica (Member # 1716) on 05-15-2015, 03:16 PM:

I used B and C series on some open air venues where you can't put projector on normal rack stand, but must use some wooden crates and similar solutions......even, newer had this isue. Could it be that they improved this on latest machines which come out from factory?

And Steve's point is wright, this would be definitly need to be covered by waranty!

Posted by Steve Guttag (Member # 268) on 05-16-2015, 08:06 AM:

This part has only been out for about a year or so. I would suggest rejecting any projector that arrives without it. I can't imagine that they wouldn't be using it on all new projectors now. It isn't all that complicated/expensive and it does seem to address the issue reasonably well. I've seen shake on all projectors and sometimes it is really caused by the platform the projector is sitting upon causing it...that isn't the projector's fault. The B-series mount, however, due to the spring loaded bottom design without any real support for the lens just highlights the issue. Depending on the projector down-angle and the weight (and center of gravity) of the lens, you have a system that is "under-damped."

You are less likely to notice this on the Minolta lenses since they are plastic/lightweight and don't put all of their mass out in front of the projector...but the Invision lenses...those things are VERY heavy and put the weight about a foot in front of the lens mount.

Posted by Marin Zorica (Member # 1716) on 05-20-2015, 02:47 AM:

I ahve one Invision lens on 19B, lens is a BIG one, since it's 2,2-5,3 (or something) ratio, but newer saw issue, and this projector is installed in hometown cinema for two years now, so watching movies often there [Big Grin]

Posted by Marco Giustini (Member # 4544) on 05-21-2015, 02:24 PM:

you won't see much difference at viewing distance on a movie. Put a focus test pattern on and you'll see what we mean.

Posted by Dave Macaulay (Member # 813) on 05-21-2015, 03:12 PM:

We never had complaints about it until the cinema did a rental with powerpoint stuff. Those static images were quite shaky - obviously cinema content was as well, but that isn't very noticeable.

Posted by Marcel Birgelen (Member # 6801) on 05-22-2015, 06:03 PM:

Cinematic content is indeed inherently different from mostly static presentation content.

You almost instantly notice the difference between a frozen frame and a still shot without any movements whatsoever. Even in those kind of shots there still is some "movement", even if it is just digital noise, film grain jumping around or tiny bits of camera shaking ever so slightly.

Posted by Gordon McLeod (Member # 33) on 05-22-2015, 06:27 PM:

so it is a Belgian Shakemecanica [Big Grin]

Posted by Steve Guttag (Member # 268) on 05-23-2015, 05:52 PM:

We just took delivery of two new Barcos and they did not have the updated lens stabilizer and they were very susceptible to shaking (big surprise there). I was quite surprised that they would still ship without the current solution that actually works.

Posted by Sam D. Chavez (Member # 1841) on 05-23-2015, 07:01 PM:

So i take it you will shake an update kit out of them?

Posted by Steve Guttag (Member # 268) on 05-24-2015, 12:44 PM:

The complaint has already been registered!

Posted by Marco Giustini (Member # 4544) on 05-24-2015, 05:14 PM:

I was told the issue was only reported by the US, please keep complaining and we may get the kit installed by default here too [Smile]

Posted by Steve Guttag (Member # 268) on 05-25-2015, 08:47 PM:

I think anyone that orders a "B" projector should just insist on it as a condition of sale.