Film-Tech Forum ARCHIVE: NEC 1200c Prism Assembly

This is topic NEC 1200c Prism Assembly in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Tom Wienholt (Member # 1510) on 02-12-2016, 02:53 PM:

When removing this assembly, a very long allen wrench is needed. Does anyone know the size needed? I do not want to purchase an entire set. Thanks!

Posted by Ian Freer (Member # 1940) on 02-12-2016, 03:07 PM:

I'm pretty sure it is removed with just a flat blade screw driver on the 1200/2000...

Posted by Mark Gulbrandsen (Member # 72) on 02-12-2016, 06:06 PM:

Yes, First pull the lens out. Then it's just a flat bladed screw driver to undo the three very long captive screws. They are also hex shaped so a driver of the appropriate diameter can also be used. Two quick disconnects for coolant on the non operating side and the massive 3 billion pin plug at the backplane. The prism is in a cage assembly and once all is disconnected it lifts right on out.

Be extremely careful with the 3 billion pin plug!

Easiest of all light engines to pull and re-install!

The 3200 and 3240 are also identical, just larger.

Mark

Posted by Steve Guttag (Member # 268) on 02-12-2016, 07:42 PM:

Um...no... the Barco DP1200-DB2000 are the easiest. Remove lens (no need to remove front security cover like on the NEC) Two coolant quick disconnects, 4 slotted captive screws...pull...no electronics to disconnect. Reverse to install

Posted by Mark Gulbrandsen (Member # 72) on 02-12-2016, 09:07 PM:

Sounds like you have one more screw to undo than I do [Eek!]

.

Mark

Posted by Marco Giustini (Member # 4544) on 02-13-2016, 05:04 AM:

Yes but no billion pins to worry about and no "cage" to move between light engines.

Probably the Christie is my favourite even though I only did that once: the LEQD is very good.

Posted by Dave Macaulay (Member # 813) on 02-13-2016, 09:35 AM:

I agree the DP1500/2000 light engine swap is super easy.
Getting at the boards is nasty though: the ELCA box is a nice idea but holding the top on with a dozen screws plus a bunch of barely accessible tiny metric nuts is cruel. Then there's changing the button panel - quite a job, and they all seem to be going flaky now. I have a few where the password is something like 5-8-5-8-5-8-5-8 because those are the only two buttons that work.

Posted by Mark Gulbrandsen (Member # 72) on 02-13-2016, 05:19 PM:

Yes Marco, However Christie still has that one DMD chip that is slightly out of focus... red I believe... Christie even admits this. I never see that in Barco or NEC. I agree the NEC cage is a pain to switch out. You can also get the entire assembly from NEC but it's super expensive.

Mark

Posted by Marco Giustini (Member # 4544) on 02-13-2016, 05:55 PM:

I have not a massive experience with Christie but at training I was told it was due to the fact that Red has a different wavelength and that it was unavoidable.

But what has that to do with how easy to swap the light engine is??

Posted by Mark Gulbrandsen (Member # 72) on 02-14-2016, 08:45 AM:

Nothing to do with it actually. This just made me think of that. Don't you find it odd that they are the only ones with that problem? I've switched out two Christie engines in about ten years.

Mark

Posted by Steve Guttag (Member # 268) on 02-14-2016, 11:21 AM:

Actually no...he his correct. RED is the toughest to get aligned up with the others, particularly blue. I've seen it on all three brands. I've noted the problem the most on the .98" machines, in general and on the 1.2" machines when looks at convergence across the width of the image.

Posted by Mark Gulbrandsen (Member # 72) on 02-15-2016, 08:30 PM:

It's almost as though on the Christie prism there is some physical constraint that they can not shim it correctly like they are able to the other two chips. In theory all three ought to be able to be shimmed into proper back focus. They get them literally perfect in three chip Tee Vee cameras... Some of those prisms are similar, just no light input function and they are much smaller.

Mark