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» Film-Tech Forum   » Operations   » Digital Cinema Forum   » NC900 light engine rebuilds (Page 1)

 
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Author Topic: NC900 light engine rebuilds
Kyle Mitchell
Film Handler

Posts: 21
From: Streator, Illinois, USA
Registered: Jan 2014


 - posted 01-10-2019 01:37 PM      Profile for Kyle Mitchell   Email Kyle Mitchell   Send New Private Message       Edit/Delete Post 
I have two with many blue pixels. What are the non-warranty options?

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16269
From: Bountiful, Utah
Registered: Jun 99


 - posted 01-11-2019 08:32 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
The only option on NC-900 is to send them back to the factory over seas. Its a 6 month wait... I suggest doing it through MIT out in Orange County.

Mark

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12294
From: Annapolis, MD
Registered: Dec 1999


 - posted 01-11-2019 09:13 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
I may be getting fuzzy on this but can't just the Blue Formatter be changed (chip and all)? On the 900, I'm pretty sure that the formatters are a part (each color) and there is no adjustment for them (as-in, they have to build them right, there are no convergence adjustments.)

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Leo Enticknap
Film God

Posts: 7128
From: Loma Linda, CA
Registered: Jul 2000


 - posted 01-11-2019 09:26 AM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
There are no Barco and Christie-style physical convergence adjusters, but on some NECs at least there are electronic ones. Never had to do it on a 900, so don't know if there are on that.

Kyle: if you're interested in returning yours for repair through us (MIT in Orange County), please give Jim Stewart a call on 714-751-7998, ext. 228, and he'd be happy to help.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12294
From: Annapolis, MD
Registered: Dec 1999


 - posted 01-11-2019 12:21 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
All DLP series 2s have "electronic" convergence...that is a function of the ICP and it can merely move by 1-pixel increments (handy if you discover the problem going into a screening but don't have time to do a full convergence...which on an NEC is somewhat annoying (NC1200/2000 because they don't leave the screws/adjusters and often things move as you snug up the screws).

The NC900C-A blue formatter assy is 79TY1241. I can't say definitively that the formatter includes the DMD but I'd think it would have to since critical alignment has to happen there in order for the non-adjustable board (and it doesn't adjust) to work. They'd need a precise jig that guarantees all of them are identical. Since they likely cannot control TI's tolerances on the packages, how they mount the DMD would be where slop would be introduced.

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Mark Gulbrandsen
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From: Bountiful, Utah
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 - posted 01-11-2019 03:47 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
On the larger projectors the DMD and formatter board are separate parts. I have a 900 engine headed my way soon to experiment cleaning...

Mark

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Marco Giustini
Film God

Posts: 2565
From: Reading, UK
Registered: Nov 2007


 - posted 01-12-2019 06:23 AM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
Have TI fixed that issue where using the electronic convergence adjustment causes an issue with some internal signal processing? (a CSC issue if not mistaken?). At the time TI was recommending NOT to use electronic convergence.

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Leo Enticknap
Film God

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From: Loma Linda, CA
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 - posted 01-13-2019 09:23 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
From the release notes of ICP firmware version 4.5, under the heading "Known issues":
quote: TI Release Notes
There is a known issue using electronic convergence with DMDs that have a DDR interface, (the 1.2DC2K and 1.38DC4K DMDs). When electronic convergence is used to move one or more colors in the horizontal direction, the computation for CSC-P7 color correction is incorrect. This could manifest itself as incorrect color particularly noticeable at the edges of objects in the picture.
I don't know whether this issue is also present in earlier versions, or if it was actually (and presumably unintentionally) introduced into 4.5. It's been over two years since 4.5 was published, so I'm not sure if TI has any plans to release a new version of the ICP firmware that fixes it.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12294
From: Annapolis, MD
Registered: Dec 1999


 - posted 01-13-2019 09:37 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
The problem predates ICP 4.5.

Oddly, Christie starts their electronic convergence at -3 for everything. NEC and Barco start at "0" for everything. Why Christie does this, I have no idea.

I've only used electronic convergence as a quick fix when there is insufficient time to do a mechanical convergence with the indication to the customer that a return call will be needed.

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Kyle Mitchell
Film Handler

Posts: 21
From: Streator, Illinois, USA
Registered: Jan 2014


 - posted 01-14-2019 12:40 AM      Profile for Kyle Mitchell   Email Kyle Mitchell   Send New Private Message       Edit/Delete Post 
The formatter board does not include the DMD and swapping out the board does not change the situation. I tried that months ago when the first one occurred, and now I've got one at another location.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12294
From: Annapolis, MD
Registered: Dec 1999


 - posted 01-14-2019 01:51 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
What you need are the DMDs. If they don't include them, they must have them as parts. I figured that the formatter was the only way to get them since alignment would be critical. NEC is pretty good about providing torque specifications if you end up changing them yourself. Torquing those right is key.

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Mark Gulbrandsen
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Posts: 16269
From: Bountiful, Utah
Registered: Jun 99


 - posted 01-21-2019 10:50 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Must also have the right tool kit to do proper torquing. I have one similar to his although mine came as a complete kit. Amazon is the cheapest source for this one. The SK will do all the hardware properly on an NEC light engine.

https://sktools.com/shop/skt0587-1-4-drive-2-36-in-lbs-adjustable-torque-screwdriver.html

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Greg Routenburg
Expert Film Handler

Posts: 159
From: Toronto, ON, Canada
Registered: May 2003


 - posted 01-21-2019 02:58 PM      Profile for Greg Routenburg   Email Greg Routenburg   Send New Private Message       Edit/Delete Post 
From what I recall of my NEC training, the DMD on the 900/1000s and the larger machines is secured to the prism separately from the formatter board. When they do the factory alignment, it must be done as an assembled unit. The formatters can be changed in the field though. I've done it a handful of times. That won't solve a stuck pixel though unless it's a connectivity issue between the formatter and the DMD socket.

The other thing that could be happening is a degradation of the formatter cables unless the captan covers have been installed. That will cause single pixel errors to occur but they usually become greater in numbers rather quickly as the machine vibrations rattle off the damaged insulation from the cables.

I can't speak for how NEC does their factory alignment but I know that Christie "Flies" their DMDs into place on the prism using some sort of robotic arm and then glues them in place. As I understand it, the Formatter with DMD are attached to the flight machine and fed an alignment signal to the formatter. The whole unit is then precisely aligned to a lit prism. When I asked if I could see it on a factory tour, the fellow walking me through said that it was well above his pay grade to let me anywhere near that room and only a very select few have ever seen the process in action. It was still nifty of him to tell me that much.

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Marco Giustini
Film God

Posts: 2565
From: Reading, UK
Registered: Nov 2007


 - posted 01-21-2019 06:49 PM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
I don’t think Christie glue their chips in place. Sony does that and convergence is indeed not adjustable mechanically - but never really experienced a convergence issue with a Sony - or at least it’s not a common issue.

Older Christie’s are not easy to adjust - as series ‘1.5’ Barco’s - later models are spring loaded as Barco does - but without easily accessible knobs.

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Carsten Kurz
Film God

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From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 01-22-2019 06:17 AM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
That would have been my question - how would you do mechanical convergence if you do a one time pick and place and glue process? Also includes the question how difficult it is to replace a single DMD with stuck pixels practically?

- Carsten

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