Film-Tech Forum ARCHIVE: Barco S projectors lens position going out

This is topic Barco S projectors lens position going out in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Dave Macaulay (Member # 813) on 12-02-2016, 10:31 PM:

Has anyone else seen this problem?
We have a few (not all) S projectors that drive all lens motors to the stops on wake or powerup. Also, the lens drifts out of focus on a lamp off/on cycle with no format macro executed. Lens position must be reset and the lens files resaved when these happen.
One cause for the gross position errors is shutdown or sleep when it's executing a lens motor movement, but that's not normal shutdown procedure. It happens too often to be the sole cause in my opinion. No possible cause for the focus drift has been found.

Posted by Mark Gulbrandsen (Member # 72) on 12-03-2016, 10:07 AM:

Are they In-Vision or Minolta lenses?

Posted by Marco Giustini (Member # 4544) on 12-03-2016, 10:31 AM:

I've seen that before and was told to wait a little longer before shutting down the projector after a format change has happened.

Posted by Stephan Shelley (Member # 8587) on 12-03-2016, 12:30 PM:

Sounds a lot like the series 1 Barco lens issues where the lens files would disappear.

Posted by Marco Giustini (Member # 4544) on 12-03-2016, 02:45 PM:

lamp on/off: may that be something moving with heat in the engine? If you turn the lamp on and then immediately off, does the focus drift?

Posted by Dave Macaulay (Member # 813) on 12-03-2016, 04:20 PM:

Both, but the one that drifts with lamp on/off is Minolta.
This site stopped powering down because it would go way out on powerup.

Posted by Buck Wilson (Member # 5885) on 12-03-2016, 05:09 PM:

Our DP2000s are constantly loosing their positions and they're never turned off

Posted by Stephan Shelley (Member # 8587) on 12-03-2016, 05:36 PM:

Buck, might want to check that the latest main software was installed. It does a lot to address the issue of the lens files going away. Looks like it is version 1.04.82. Also crowding projector automation cues adds to the issue. Make sure you give it time to finish the macro before you send a lamp or dowser cue. Or make sure it has finished the lamp cue before sending a macro cue.

Posted by Dave Macaulay (Member # 813) on 12-03-2016, 06:29 PM:

I'm not at the site: they are doing CG and use the system for shot/scene test screenings... turn lamp on, screen for a few minutes or hours, turn lamp off - no schedule. Next time, the image is out of focus but position and zoom are either unchanged or "close enough".

Posted by Marco Giustini (Member # 4544) on 12-03-2016, 06:30 PM:

quote: Dave Macaulay
This site stopped powering down because it would go way out on powerup.

Barco S like dust - so much that they eat it all and you then can see it in their bellies - in the light engine [Frown]

DP2000: what Stephan said.

Posted by Steve Guttag (Member # 268) on 12-04-2016, 06:55 AM:

I don't, currently, have any "S" series Barcos so I cannot comment on that aspect of this discussion.

With respect to the DP2000. Software wise, 1.4.82 is not only a stable version, it is likely Barco's last version (they haven't made any DP2000s in 7-years!

Things to do when you have a series 1 with drifting lenses. Clean ALL of the connections between the lens and the signal backplane. That is, clean the connectors on the lens to the lens mount, the cables from the lens mount to the harness (there are connectors all grouped together behind the boot of the front cover) and then where those cables plug into the signal backplane behind the ELCA box.

Series 1 projectors don't have a home/return to re-zero itself. It merely counts pulses in each direction to retrace its steps between lens positions. If you have any "dirty/staticy" connections, it WILL lose count. I have had DP2000s that were routinely losing their settings that NEVER had the problem again after doing this.

Another thing to do is to periodically (at least once per year), delete ALL lens files, select a different lens of the same brand in Communicator and then reselect the correct lens. This will force the projector to start at square (well, position) 1. Then recreate your lens stops (the fewer the better). And remember, a Series 1 recreates your steps so you want to get to your lens position on the 1st try for each position (x,y, zoom and focus). If you tweak it by nudging it a little bit back and forth, it will need to recreate each one of those steps and that will increase the likelihood of it not hitting its mark next time and increase the chance of missing things.

Posted by Marco Giustini (Member # 4544) on 12-04-2016, 01:31 PM:

are you saying that if I spend 10 minutes tweaking the lens on a Barco S1 the lens will run 10 minutes when it's recalled??
Barco S1 are slow and will go past the target point to account for mechanical play if you saved your position from the opposite direction you are coming from - and that looks like the lens is tracing your last movements because it is painfully slow - but I've never seen a Barco S1 doing what you suggest, unless the wrong lens is selected, then it does weird things.
Thanks for the tip of cleaning ALL the connections.

Posted by Steve Guttag (Member # 268) on 12-04-2016, 01:51 PM:

My mistake...it keeps track of the direction you were going while adjusting. So, if you zoom out for scope and you go too far and then zoom back a little, it will have to also zoom out too far to bias the gears right before zooming back. So you are better off if you zoom too far to then zoom back until you are again too small and then nudge it back to where it should be (so your effective direction is the one direction). This will allow it to just zoom in the one direction until the target number is reached.

This is explained (even graphically) in Info Ts 761 (older) and 877 (replaces 761). The other potential danger is if you are near a limit, when the projector has to overshoot and come back, it runs the risk of hitting the limit and the dreaded "target not reached" yellow tail light results. So it is always best to make all changes in a uniform direction with respect to the previous setting. This applies to all projectors that I've come across. This particularly affects Barco Series 1 projectors and NEC where they don't have any means of zeroing out the lens mount (though the NEC can sort of crudely do it. Christie's initialization is also crude but it takes care of the overhead of biasing the gears as you go as one changes direction, it rocks the adjustment to rebias the gears. So, again, you are best served by moving in a uniform direction, if at all possible.

Posted by Carsten Kurz (Member # 5396) on 12-05-2016, 04:22 AM:

Dave - did you check with them their shutdown procedure? Because the S and E allow to do it in different ways and maybe they haven't been educated on how to do it properly. Also, is this a problem that occurs from the start, or did it develop after some time?

- Carsten