Prism contamination

[Marcel Birgelen]

Tilt-Rotate DLP chips have been around since 2013-ish, but have previously been used primarily in smaller, lower power assemblies. I'm not aware of TI having updated their design, but I may have missed that. The DCI DLP chips aren't available for the general market and as such, not all updates are published to the public by TI.

If nothing changed at the TI end, it has to be the light engine design itself. Since the increased pixel failure rate is probably due to cooling issues, that would indicate a redesign of the light engine, which, afaik, also didn't happen yet.

In general, I'd always go for the bigger chip size if given the choice, even if the costs are a more bulky light path and a more bulky machine. While there are lots of little differences between DLP chip designs, bigger mirror almost always means more contrast...

Mike's theater was previously able to fit at least one 35mm projector in the booth, so I doubt fitting this machine in there should be a problem. Only getting those things up there to those old theater booths often is quite a challenge. Those booths clearly weren't designed for regular large equipment swaps.

I will go out on a limb here and say it is definitely contamination as I have seen that exact same thing before and I pulled the prism and got down to where I could even see the liquid (seriously, it comes through the filter and that fan right above the prism is what is pumping the strained liquid contaminated air into the prism. The migration may seem like it is moving fast but remember, that prism is only .98" on the diagonal and we are being shown the 2.39 portion or the middle 3/4s or so. The magnification is so great, a little movement will seem like a lot. This also happened over a long time for it to make it this far but it is in there.

You've seen the contamination first hand, as you actually pulled the prism. There were no means to get the contamination off of the prism via any low-tech solution without damaging it beyond repair?

[Steve Guttag]

Marcel, so you offer speculation on the light engine design and if TI is or is not working on a re-design? How about I heard 1st hand and leave your speculations out of it. Have they really been making 4K TRP DMDs since 2013? I doubt it but that is speculation on my part. In speaking to multiple DLP manufacturers, the TRP chips indeed have a higher rate of stuck pixels though not as high as what has been experienced by the 4K ones used in cinema machines.

And yes, I've have, 1st hand pulled a prism and was able to see the contamination though if one gets down to the DLP part, you better have a lot of time on your hands or a jig to get them in alignment because it gets to the bottom DMD, the one you can't adjust while the prism is in the machine. This is something that Strong, that does have the facilities, can pull/clean and realign. Plus, one can get a fully cleaned prism assembly rather than a hack job in the field. Again, with a enough time, I'm sure it can be done in the field but I've seen one of these being realigned it can get rough pretty quick.

[Marcel Birgelen]

Marcel, so you offer speculation on the light engine design and if TI is or is not working on a re-design? How about I heard 1st hand and leave your speculations out of it. Have they really been making 4K TRP DMDs since 2013? I doubt it but that is speculation on my part. In speaking to multiple DLP manufacturers, the TRP chips indeed have a higher rate of stuck pixels though not as high as what has been experienced by the 4K ones used in cinema machines.

The first TRP DMDs hit the market around 2013 in the form of pico modules (for micro projectors). That was their first broad application. The redesign of the mirror allowed them to shrink the DMD so it made sense for micro-projection applications. That's no speculation, but something that's easy to look up. Also, you see that TRP made it slowly into the 4K designs, to allow for smaller DMD designs, yet achieving 4K resolution. That's also no speculation, but a trend that can be easily seen across the differerent cross-market DLP offerings.

And if you read my post correctly, I'm not saying that TI is not working on a redesign. I frankly don't know and don't offer any speculation on that part and if I did, it was probably covered by some NDA. I'm clearly stating: I'm not aware of TI shipping a redesigned version of their TRP-based TI DLP chips. So, if TI is working on a redesign, it looks like those DMDs didn't make it out yet, or I must have missed something.

And if anything else changed, that change must have been part of the light engine and AFAIK, nothing changed there either. And that part was more of a question than speculation.

And yes, I've have, 1st hand pulled a prism and was able to see the contamination though if one gets down to the DLP part, you better have a lot of time on your hands or a jig to get them in alignment because it gets to the bottom DMD, the one you can't adjust while the prism is in the machine. This is something that Strong, that does have the facilities, can pull/clean and realign. Plus, one can get a fully cleaned prism assembly rather than a hack job in the field. Again, with a enough time, I'm sure it can be done in the field but I've seen one of these being realigned it can get rough pretty quick.

Well, that's kind of the reason why I'm asking. I clearly don't have the facilities and aren't qualified to align a prism, yet you pulled it out. I guess the intentions were to put it back in? If you make the efforts to pull it out, you know you're going to have to realign it anyway. So that's why I asked if you considered to clean it and if it's even feasible to clean it in the field.

[Steve Guttag]

Marcel, you again try to use a different DMD that used the same similar technology to somehow make a generalization on the the specific 4K TRP problem as witnessed in the industry. Nobody was disputing that the TRP DMD originated when you state. The 4K DMD, as used by digital cinema (which is the only variant that matters in this forum), uniquely has shown a problem to this industry. I'll tell you what; why don't you ask the projector manufacturers if you don't have a direct link to TI if TI is working on a redesign of the 4K TRP (in the .98" size, to be more specific) to address mirror stick and report back to us. Otherwise, what you present is speculation, with respect to this problem.

Onto the prism. Yes I pulled it to see if I could field-clean it. The liquid issue was quite evident since it wasn't just on the inside of the assembly. As one could imagine, before it got in, it was already on the outside too and migrating. I went as far as I was willing to go, given the conditions of the situation. I cleaned what I could but I didn't want to take that screen down by getting into a situation where I couldn't, at least, keep it was in (do no harm). I recommend to the client to proceed with an RX prism.

[Leo Enticknap]

I can't provide any more detail as to where and from whom I heard that there was a hardware revision in progress to the TI DMD chips used in the SP4K .98" light engines, as I don't have permission to do so: all I can say is that I have no reason to disbelieve or doubt it.

There definitely has been a hardware revision to the light engine. As we're all aware, the first ones were also susceptible to convergence drift, a situation that was exacerbated by the fact that when swapping them out, it was physically possible to route the hoses such that one of them applied pressure to the edge of one of the formatter boards, thereby making it impossible to converge (although even with the hoses routed correctly, the convergence would still drift, though in many cases an adjustment after around 200 hours from new was all that was needed: it would stay put after that). Cinionic provided a cheat sheet with photos showing the correct and incorrect hose routing. Around the back end of last year, I swapped out one (I can't remember if the issue was dead pixels, convergence drift, or both), and noticed that the replacement had thinner hoses than those on the original light engine (the difference was clearly visible when the hoses were attached to those on the other side of the quick release couplings), and that one of them was slightly shorter, making it physically impossible to route incorrectly, such that it pushes down on the edge of the board. Every SP4K .98" LE I've installed since has had this new coolant hose arrangement, and I haven't seen or been told of any convergence drift problem with a "new hose" LE after installation and initial adjustment.

[Marcel Birgelen]

@Leo: But you're allowed to state that it is in progress, so, it's not here yet?

I wasn't aware of that first redesign and the hose situation is something that would've enraged me, because those rudimentary "design errors"are the type of things you expect to be solved before they ship it to you as a finished product.

Marcel, you again try to use a different DMD that used the same similar technology to somehow make a generalization on the the specific 4K TRP problem as witnessed in the industry.

Steve, I'm not even aware of any specific problems with the TRP chips for other designs. The only thing I know is that they entered the field of "high powered projectors" relatively recently. The most common issue of premature DMD failure is overheating and from what I've been told, the TRP design is more prone to this, because of less tolerances in the design.

Nobody was disputing that the TRP DMD originated when you state.

Have they really been making 4K TRP DMDs since 2013? I doubt it but that is speculation on my part.

Yeah technically, you're not disputing it but doubting it.
And no, they haven't been making 4K TRP DMDs since 2013 (The first TRP designs were all below 2K. I think the first prototypes of UHD TRP DMDs became available around 2015-ish), but they didn't design a specific mirror for DCI chips either, that would've been far to cost-prohibitive.

The 4K DMD, as used by digital cinema (which is the only variant that matters in this forum), uniquely has shown a problem to this industry. I'll tell you what; why don't you ask the projector manufacturers if you don't have a direct link to TI if TI is working on a redesign of the 4K TRP (in the .98" size, to be more specific) to address mirror stick and report back to us. Otherwise, what you present is speculation, with respect to this problem.

I clearly indicate what parts of my narrative are speculation, and the ONLY part that's speculation is what the possible cause may be. The rest is just facts dressed up with lots of words. If you know more about the underlying case and are allowed to share, by all means, enlighten us.

Butbutbut... Like you mentioned itself, this is a discussion forum! Maybe you're allergic to speculation, (especially from someone else ), but all good (and most bad) science starts with a hypothesis (a nice word for: speculation), so I don't know why it should not be allowed, as long as it's not presented as facts. And who doesn't love some good gossip from time to time? :P

Onto the prism. Yes I pulled it to see if I could field-clean it. The liquid issue was quite evident since it wasn't just on the inside of the assembly. As one could imagine, before it got in, it was already on the outside too and migrating. I went as far as I was willing to go, given the conditions of the situation. I cleaned what I could but I didn't want to take that screen down by getting into a situation where I couldn't, at least, keep it was in (do no harm). I recommend to the client to proceed with an RX prism.

Last question (probably) on the prism situation, out of curiosity and maybe even some practical info for future cases: Did the cleaning you did yield some positive effect, despite the, most likely, improper alignment you ended up with?

[Steve Guttag]

The cleaning that I did had zero improvement to the problem...it was further inside and likely right on the DMD face itself.

As to the other 4K TRP...I have zero problem with discussion. I do have a problem after something has been presented with 1st hand knowledge with an alternative position based on speculation, which is how you presented your information. You aren't adding to the discussion then, you are blurring it. If the cause is heat, it may be but that is TI's problem. I will say that nobody that I've been in discussions with has offered that as the primary culprit. I will also state that the frequency of stuck pixels has no correlation to lumen output (which should correlate to heat). I've had more SP4K-12C projectors have a stuck pixel but that is because I have MANY more 12s out there than the rest of the line. Thus far, all of the SP4K-25 (two) have had a stuck pixel but two units is not a basis to form statistical inference. To the best of my knowledge, neither have had a repeat (it will be just about a year for one and over a year for the other). That said, all of the SP4K systems I've put in are running below 50% power and most are in the 20-35% range. So, I'd think I'd be a the low-end of the lumen/heat scale.

[Mike Blakesley]

What's funny to me about the above discussion is that a "stuck pixel" is the problem I was dreading and expecting to turn up as our projector got older... I never expected this thing we're getting, which is now covering about 1/3 of the screen.

We've pretty much decided to go ahead and get a new projector, since there is one available 5 weeks out and I was already planning to pull that trigger in the next year or two anyway.

What I'm currently struggling with is how to handle the public-facing side of things. Should I put up an explanatory sign and offer refunds if people get upset? I probably won't do anything until after Little Mermaid ends because you don't really see the problem for 90% of the movie anyway, at least not yet. What makes me the sickest is we're still going to be "blue" during "The Flash" and probably part of "Mission Impossible," just the two biggest movies of the summer, but I guess that's show biz. Timing on this thing couldn't be worse. Gonna be a long 5 or 6 weeks.

[Frank Cox]

I haven't had anything here that made the picture since I got the digital system (so far it either works or it doesn't), but I did have some films back in the day that were in pretty crappy shape and when that happened I always told people that "this movie is really scratched up and it doesn't meet my standard for showing a movie here" when they came in to buy their tickets. If they decided to buy their ticket anyway and came back out shortly after the movie started I'd give them a refund.

It wouldn't be fair to sell a ticket for a substandard show without at least giving people a warning and an opportunity to change their mind.

[Marcel Birgelen]

The cleaning that I did had zero improvement to the problem...it was further inside and likely right on the DMD face itself.

I think this is worthwhile information. At least it shows that the prism simply isn't a field-serviceable item.

As to the other 4K TRP...I have zero problem with discussion. I do have a problem after something has been presented with 1st hand knowledge with an alternative position based on speculation, which is how you presented your information. You aren't adding to the discussion then, you are blurring it.

After 4 hours stuck in traffic, having to endure Coke from a Freestyle machine, being served probably the most terrible trial at a hamburger since the invention of patties on on buns, while waiting for the traffic to clear... those words coming from you, Steve, I consider a compliment. I love you too.

If the cause is heat, it may be but that is TI's problem. I will say that nobody that I've been in discussions with has offered that as the primary culprit. I will also state that the frequency of stuck pixels has no correlation to lumen output (which should correlate to heat). I've had more SP4K-12C projectors have a stuck pixel but that is because I have MANY more 12s out there than the rest of the line. Thus far, all of the SP4K-25 (two) have had a stuck pixel but two units is not a basis to form statistical inference. To the best of my knowledge, neither have had a repeat (it will be just about a year for one and over a year for the other). That said, all of the SP4K systems I've put in are running below 50% power and most are in the 20-35% range. So, I'd think I'd be a the low-end of the lumen/heat scale.

Well, that's the kind of info I was expecting as a reply. So, based on your own statistical input, it's most likely not power/heat related.

For me (and probably also for other prospective buyers), it's also good to know that, according to the available information, the .98" TRP models currently being shipped haven't had a design update to combat the stuck-pixel problem, but that there is, if I interpret Leo's remarks correctly, an update in the pipeline coming from TI.

See, I can call Barco on Monday and ask them and I'm sure they'll do a fine job at downplaying the problem. But if I don't need a new projector RIGHT NOW, I'd rather hold out until the potential problem has been solved. Even if Barco honors replacements as part of ongoing warranty and your projector ends up performing fine, you simply don't want to end up with a light engine which you suspect of a potential major design flaw.

What's funny to me about the above discussion is that a "stuck pixel" is the problem I was dreading and expecting to turn up as our projector got older... I never expected this thing we're getting, which is now covering about 1/3 of the screen.

I consider the stuck-pixel problem in DLP to be a bit of a cancer... Chances of getting it are increasing if it gets older, but many DLP machines will have a long life without any.

Then there also is a difference in which state a pixel is stuck. If one is stuck in the "off" state and not in the middle of the picture, those will barely draw anybody's attention. On a 4K DMD, an always-off "sub-pixel" is even less noticeable than on a 2K DMD.

We've pretty much decided to go ahead and get a new projector, since there is one available 5 weeks out and I was already planning to pull that trigger in the next year or two anyway.

Great news for your patrons, probably less great news for your bank account, but a single, independent screen, showing movies in 4K laser is at least noteworthy. Maybe try to get some local news involved?

What I'm currently struggling with is how to handle the public-facing side of things. Should I put up an explanatory sign and offer refunds if people get upset? I probably won't do anything until after Little Mermaid ends because you don't really see the problem for 90% of the movie anyway, at least not yet. What makes me the sickest is we're still going to be "blue" during "The Flash" and probably part of "Mission Impossible," just the two biggest movies of the summer, but I guess that's show biz. Timing on this thing couldn't be worse. Gonna be a long 5 or 6 weeks.

That's always a difficult decision to make... I'm speculating here (alarm!), but I guess most of your patrons are regulars. I think I'd be open with them about the presentation problems you're facing right now, but that a completely new, 4K laser projector is underway. Maybe, you can make it part of a promotion to market your new and upcoming projector and give them discount vouchers, so they can enjoy the new, and improved image as soon as the new projector arrives?

Still, be careful with advice from random strangers on the internet.

[Mike Blakesley]

We've been talking about just giving everyone who goes to the show a free pass for a future show, starting after Little Mermaid ends. That'll be a lot of freebies out there floating around, but (a) we'll still get their concession money when they redeem them, and (b) a lot of them will get lost, forgotten about, etc. and (c) maybe some of them will come with a new "paid" person. I haven't completely decided to do this though, waiting on the overall time-line.

[Frank Cox]

Be sure you put some kind of an expiry date on those. You don't want someone hauling one in ten years later.

(I still get the occasional gift certificate that I gave away as prizes for this and that during the first year that I had my theatre. 28 years later....)

[Marcel Birgelen]

We've been talking about just giving everyone who goes to the show a free pass for a future show, starting after Little Mermaid ends. That'll be a lot of freebies out there floating around, but (a) we'll still get their concession money when they redeem them, and (b) a lot of them will get lost, forgotten about, etc. and (c) maybe some of them will come with a new "paid" person. I haven't completely decided to do this though, waiting on the overall time-line.

I think, that's extremely gratuitous, maybe overly so.

I'd say that if you warn them beforehand that the picture quality isn't up-to-par, but a new, fancy laser projector is underway and people still buy into it, it's fair to give them some form of compensation for the degraded picture. An entire "free meal", while honorable, is a pretty big freebie, especially since you're going to hand them out to everyone in the coming few weeks.

Putting an expiry date on them, like Frank indicated, may also not be a bad idea. Expiry dates do come with some legal limits though, depending on local laws and regulations. A gift card needs to be at least 5 years valid, but since this isn't technically a gift card, but a "promo" (people didn't pay extra to buy the voucher), you're probably fine putting in an earlier expiry date on them.

But, to misquote THE Dude from that 1998 movie: You know, that's just like my opinion, man.

[Randy Stankey]

How about you give out invitations to the grand opening of your new projector?

[Steve Guttag]

Marcel,

Are the SP4K-C projectors available in your part of the world? They've been on "pause" around here for quite some time. I've had them on order since December and until the stuck pixel issue is resolved, they aren't shipping. What Barco did do was quickly come up with the SP4K-15B through the SP4K-25B to have something to offer in that lumen range and 4K. The lower-lumen SP4K-B do not show up on the products page and show as discontinued on the support page (Barco's) (I've seen different messages, including "not available in your area" on the SP4K).

Mike, why not claim that the cyan or "aqua tinting" was done for "theming" on Little Mermaid! Or, explain the issue and assure people that you have a replacement projector ordered. I like the idea of an "invitation" to see the new projector in action.