quote: Alexander Merlin

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removed formatter boards and cleaned DLP chips

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Posted by Mark Gulbrandsen (Member # 72) on 10-28-2015, 03:27 PM:
 
There are things that some of us are not afraid to do. I have also had the occasion in the past year to dismantle a prism in order to clean it. You just need the correct tools and patience.

Mark
 

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Posted by Marco Giustini (Member # 4544) on 10-28-2015, 04:52 PM:
 
I'm just merely pointing out that removing chips is not exactly supposed to be done and I don't know what kind of coating is there. I also don't have data on S-series brightness so I cannot comment on that either but allow me to feel sceptical if I read about poor brightness and chips being removed in the same paragraph.
 

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Posted by Dave Macaulay (Member # 813) on 10-28-2015, 04:54 PM:
 
The internal CLO sensor reading should be independent of any light engine stuff, it's measured at the mirror before the LE. The "S" CLO readings were pretty weird with early software but it seems better now: I'm not sure how the projected image brightness would affect the reading at the CLO sensor but it did, quite a bit.
Lamp hour fade seems more severe with the small gap 0.69" chip lamps than with the C or B projectors but if you get that much drop with a new lamp compared with the original levels... something is strange.
Are you certain the installers were honest with their original luminance readings? After specifying the small projector, there's some incentive for the integrator to report excellent light readings if it's not bright enough. Barco's lens/projector calculator is good... but unless you put in realistic light path loss and lamp aging factors it selects impractically low power projectors.
Plus: Are your screens losing reflectance somehow? I worked with one 3D site where a chemical processing businesses nearby caused rapid deterioration of the reflective screens.
 

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Posted by Marco Giustini (Member # 4544) on 10-28-2015, 06:15 PM:
 
Good point. Also, do you have high gain screens? If so, your installer may have - intentionally or not - pointed their meter to the hotspot. The brightness difference on a high gain screen can be huge.
 

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Posted by Alexander Merlin (Member # 9129) on 10-29-2015, 03:01 AM:
 
Dear Colleagues,
I work in integrator company and I installed about 25 projectors S series include this, and all projectors have low brightness after one year using.
I use JETY with actual virification date. Data about measure - really. I want to understand why after annual maintenance the brightness is 15-25% from use start day? Optical path is clean. For clean of reflector I use Lens cleaner. The screens is not subjected to chemical treatment. (interesting case).
Alexander
 

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Posted by Marco Giustini (Member # 4544) on 10-29-2015, 04:48 AM:
 
Was the lamp being used on the two measurements the same lamp, or a brand new one anyway?
What does the CLO sensor says? Does it report the same loss of light?
 

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Posted by Alexander Merlin (Member # 9129) on 10-29-2015, 05:07 AM:
 
Ushio 2,2 kWt, the same.
I would like to know somebody has problem with brightness on S seriers projecotors? or all projectors S series have perfect brightness in the worldwide?

Alexander
 

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Posted by Marco Giustini (Member # 4544) on 10-29-2015, 05:35 AM:
 
same = same hours. Obviously a brand new 22BAF will be MUCH brighter than a 1000hours old one.

Some drop in brightness is expected to be honest. I believe this is true for any projector.
Not 80% of course.

Also, and sorry if I'm teaching you how to suck eggs, did you re-align the lamp after maintenance? And again: what does the CLO sensor says? Does it report the same massive drop or does it show roughly what you would expect?
 

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Posted by Steve Guttag (Member # 268) on 10-29-2015, 07:22 AM:
 
Generally, if a projector is losing brightness, it is a strong indication of dirt build up on optics within the projector. There is a lot of forced air in a projector and none of the filtering systems are perfect. I've cleaned a projector's optics (from reflector to light engine) and increased brightness by over 10% and the projector was only in operation for a bit over a year.

Drywall dust is NASTY stuff and will show up as this VERY fine powder in the projector.

I just saw an NC900 projector (NEC) with about 3000 hours on it...looked clean on the outside and the filters looked "normal". Inside, drywall dust was all over the optics and fans.
 

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Posted by Dave Macaulay (Member # 813) on 10-29-2015, 11:41 AM:
 
Barco claims their light engines are sealed airtight. I've never had any LE dirt problems with one. Christie and NEC, yes.
Looking at records for one 10S I see the light has dropped from 14 at 2200W to 8 at 2006W as the Osram 2200W lamp has gone from 1600 to 2600 hours. Another one with an Ushio 22BAF has increased power 30% after 1000h (in two years, summer only location) to hold the same brightness.
 

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Posted by Steve Guttag (Member # 268) on 10-29-2015, 12:06 PM:
 
Barco's claims are for the DMDs only. Both ends of the integrating rod, cold mirror, fold mirror, notch filter and any lenses between the lamp and the prism are open as well as the outlet of the light engine, including the lens inlet pupil. Though the light sensor readings will only notice dirt up to the fold mirror.
 

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Posted by Marco Giustini (Member # 4544) on 10-29-2015, 02:02 PM:
 

quote: Dave Macaulay

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I've never had any LE dirt problems with one. Christie and NEC, yes.

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Same here.

Steve,
All the lenses and filters inside the LE, including the integrator case, are relatively sealed. I wouldn't expect much dust going in there.

One place which gets dusty is between two prisms, just before the lens end. There is a small gap between them.
 

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Posted by Steve Guttag (Member # 268) on 10-30-2015, 07:32 AM:
 
Pull one down and look for yourself with an LED flash light (they tend to show the dust off very well). Heck, just look at the inlet of the integrating rod via the, likely, dusty cold mirror.
 

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Posted by Marco Giustini (Member # 4544) on 10-30-2015, 10:10 AM:
 
I have opened one of those in the past to replace a cracked lens and I noticed how sealed and clean the area was.

A little dust visible with a flashlight does not mean that you will have a visible effect on screen. And coatings may be more important that a few specs of dust.

I cleaned some very - very - dirty Dolby 3D wheels some months ago. I thought I would have a sensible increase in brightness, and in fact the difference was negligible.

Contrast: yes. Brightness, unless the optics are really dusty I don't think it's a problem.

That said, I always clean the reflector, the cold mirror, the integrator's face etc. etc.
 

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Posted by Steve Guttag (Member # 268) on 10-30-2015, 12:32 PM:
 
I don't know what to tell you...the owner of the theatre wanted the projector cleaned...so to let myself know what the difference was, I turn the projector on and aligned the lamp...measured it (with a color meter to ensure that I was at .314/.351)...cleaned the optical path completely...measured it again and I was up 10% in brightness. All that was removed was dust.
 

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Posted by Sam D. Chavez (Member # 1841) on 10-30-2015, 01:12 PM:
 
One of the many areas you cleaned made way more difference than the others.

Any guesses which surface?

Sort of related to this is I have 24 solar panels on my roof. It has not rained out here since anyone can remember so I cleaned the panels with soap and water but first looked at the output on two consecutive cloudless days at the same time and the output hardly increased at all.
 

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Posted by Marco Giustini (Member # 4544) on 10-30-2015, 01:37 PM:
 
Steve,

I was not clear, sorry. What I meant was that what's inside a Barco light engine (those lenses you mentioned after the integrator) will probably have a negligible effect on brightness and that a few specs of dust on them is not worth cleaning them.

On the contrary, the prism exit, the lens end, the cold mirror and the main reflector can get quite dusty and indeed I don't struggle to believe that you can get a 10% improvement, particularly on a dusty machine. Never measured myself on a DLP to be honest.

I reckon the most critical areas are the prism exit/lens end (that will also affect contrast) and the main reflector.
 

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Posted by Steve Guttag (Member # 268) on 10-30-2015, 02:28 PM:
 
Sam,

I think it was a cumulative effect. I tend to think those areas with smaller surface (integrating rod) are more apt to play a role since the percentage of obstruction is going to be higher than the same dust amount spread over say the area of the reflector. But that is just a guess.

Marco, I agree, once the light leaves the fold mirror, there is going to be very little opportunity to get any significant dust in there until you start exiting the prism area to the lens as well as the lens itself.
 

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Posted by Marco Giustini (Member # 4544) on 10-30-2015, 02:43 PM:
 
I meant the cold mirror though (the one after the main reflector). I agree on the integrator's outer face but I don't think that opening the integrator compartment and clean what's inside could bring any benefits to the projector.

Have you noticed lots of dust build-up in there?
 

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Posted by Dave Macaulay (Member # 813) on 10-31-2015, 08:48 AM:
 
It depends on the air quality. Projector air filters can get disgusting when booth air is drawn from the cinema - not unusual due to the lamp exhausts, and it's rare to pull make-up air from outside. The cinema air is always full of dust just from the people traffic. Popper smoke is the most common serious problem. It's often not completely (or at all) exhausted, either to save money or intentionally to flood the building with "alluring" popcorn stink. Drawing air from the lobby is worse than getting it from the auditoriums where the smoke has usually dissipated. Singles and small cinemas are the worst, multiplexes usually manage HVAC properly.
If I can smell popcorn stink in the booth when it's popping I know there will be some nasty cleaning to do. The tar that gets on air filters also, naturally, coats the projector optics. After needing strong chemistry to get the Barco metal filters clean once, I got curious and measured a fair color shift (by numbers, I couldn't see it by eye) after cleaning tar off the lens faces, lamp envelope, lamphouse collectors, UV plate, folding mirror, integrator entry, and prism exit face. The screen luminance didn't jump a lot though.
Getting a few miles off topic but... that popcorn smoke tar can be very difficult to clean off. Isopropanol works safely on coated optics but it takes quite a while to dissolve tar. For Barco metal (or S series paper) filters the service manual procedure using sodium carbonate works well - if you have (1) boiling hot water (2) a big enough basin or sink and (3) lots of time for the filters to soak. If you like your fingerprints, wear rubber gloves.
Swish 5100 cleaner is the best I've found for quickly doing the metal filters but you absolutely need good rubber gloves and a respirator would be nice.
 

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Posted by Carsten Kurz (Member # 5396) on 10-31-2015, 08:54 AM:
 
Funny - Christie has JUST released two new support documents, one named:

Christie Degrading Optical Performance Technical Bulletin

The other:

Cleaning Projector Optics

- Carsten
 

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Posted by Marco Giustini (Member # 4544) on 10-31-2015, 12:53 PM:
 
I noticed that too. Pretty much useless though. It basically says to dust the optics and if still dusty... to clean them!

Oh well, there must be a reason for that. Maybe similar reason to release a bulletin to "warn" "engineers" that when swapping a Dolphin card in a Doremi server great care should be adopted to avoid scraping components off the motherboard while doing so.

Ah-ehm.
 

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Posted by Steve Guttag (Member # 268) on 11-01-2015, 05:06 AM:
 
I would have thought that Acetone would be harmful to the various coated surfaces yet that is the solvent they are recommending if things don't come clean with just air. I know, once upon a time, I have used Acetone to turn colored Christmas lights clear. It will definitely dissolve popcorn tar too.
 

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Posted by Gordon McLeod (Member # 33) on 11-01-2015, 10:41 AM:
 
100% Acetone was always the recomendation for cleaning optics in laser light shows
 

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Posted by Mark Gulbrandsen (Member # 72) on 11-01-2015, 11:04 AM:
 
The only product that you can buy that will not scratch the coating or leave any residue or streaks from cleaning is Pancro Lems Cleaner that I mentioned earlier. It does not have acetone in it, it is non toxic. Acetone is really bad for you and you do not want to expose yourself to a lot of it.

Mark
 

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Posted by Carsten Kurz (Member # 5396) on 11-01-2015, 03:08 PM:
 
Sony recommends:

'Absolute alcohol (ethanol: 99.5% or more, propanol: 99.5% or more)'

in their maintenance manuals, not only for glas surfaces, also for their sandwich color filters and mirrors.

I inquired at a german supplier for various ethanols, and they told me they sell their 99,9 ethanol to Leitz/Leica for optical cleaning applications.

Christie recommends Acetone and Isopropyl for specific parts only, so they should know why. And I wouldn't recommend Acetone for this job in general.

Acetone is actually not very harmful:

https://en.wikipedia.org/wiki/Acetone#Toxicology

- Carsten
 

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Posted by Steve Guttag (Member # 268) on 11-02-2015, 06:04 AM:
 
The two biggest harms with Acetone is skin contact (mitigated by gloves) and proper ventilation. Secondary is its ability to burn.

Note even Isopropyl Alcohol has both of those though not as pungent on the vapor side. Most don't take the skin contact portion as seriously as they should. As the water content goes down, the more harmful it is to skin contact.
 

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Posted by Carsten Kurz (Member # 5396) on 12-02-2015, 04:56 PM:
 
BTW - what does everyone use as wipers/tab for cleaning optical surfaces?

- Carsten
 

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Posted by Steve Guttag (Member # 268) on 12-02-2015, 08:24 PM:
 
Depends on what it is I'm trying to remove. I start with the least contact as possible and work up from there. So air is where I start...then a very soft brush. However, I often find myself using lens tissue and lens cleaner when the substance is baked on a bit. I fear that any form of dry rubbing would actually tend to scratch the surface more than the fear of using lens cleaner (alcohol based).
 

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Posted by Carsten Kurz (Member # 5396) on 12-02-2015, 09:27 PM:
 
I found this a few minutes ago:

http://www.edmundoptics.com/technical-resources-center/optics/cleaning-optics/

- Carsten
 

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Posted by Marlon Martins (Member # 8823) on 12-02-2015, 11:34 PM:
 
I created a topic a few days ago on this problem also (a 10s). i was wondering that may be the air exhaust was not getting proper air flow (pipes were too long, motor was not able to push properly).

a barco 19B was installed in the place of the 10s, and the projector was alerting about "no exhaust flow". after removing the pipes, the problem disappeared. the people who installed was thinking the exhaust sensor was bad, but no, was the exhaust piping. (the same exhaust the 10s was using previously)

after transporting the 10s projector, the front lens was removed, and was covered with dust in the internal lens surface.

so, when we install the 10s again in the other room, i will highly suggest a "full-cleaning" of the optical components, and test the brightness again. then change to a new lamp, and test again.

we need to know where the problem is... (the projector is less then a year old)
 

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Posted by Carsten Kurz (Member # 5396) on 12-03-2015, 06:26 AM:
 
You mean, it was IN the lens, or ON the projector side lens surface?

VERY strange, but at least an explanation for the reduced brightness...

Well, you know now how to clean a lens ;-)

- Carsten
 

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Posted by Marlon Martins (Member # 8823) on 12-03-2015, 01:27 PM:
 
the lens was covered in dust (the part of the lens that goes inside the projector) did not look at the projector itself.

soon we will dig deeper in this problem
 

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Posted by Marco Giustini (Member # 4544) on 12-03-2015, 03:02 PM:
 
I thought you said you cleaned the optics - including the DMDs and the prism! - and you didn't clean the back of the lens which is the first to get dusty?

Carsten
The back of the lens normally gets really dirty on a Barco. An S projector I serviced was awful because the filter seal was not fully touching the filter frame (by design) and unfiltered air managed to get in.

In fairness on Christie projectors the area prism-lens is sealed and no dust whatsoever can cover that delicate area.

Is there a flow switch on an S machine? Don't think so.
 

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