NC1600C Convergence

[Jarod Reddig]

To me this is a big enough reason not to ever go with an NEC, unless newer models fixed this issue.

[Marcel Birgelen]

To be fair, when the chip is bolted down, it rarely drifts. Spring-mounted ones are less stable but adjusting them is also much easier and faster.

In my experience, it really depends on the projector itself. It probably also has something to do with how well-maintained the thing is. But the heating and cooling cycle, over the years, certainly has an impact on convergence, no matter of how your DMDs are mounted in-place. I guess if your machine gets very hot, either due to constant high lamp power and/or improper cooling, chances of convergence drift increase. I've also seen convergence issues on machines that have been transported around a lot.

I think the best way to implement stuff in general (not just color convergence) on those kind of machines is to expect that everything that can, will eventually drift. Also, a micrometer on the scale of a DMD will equate to (possibly many) millimeters on screen.

Somehow it's still strange that a budget 3LCD projector often comes with motorized/actuated panel adjustments, but a projector costing a small fortune doesn't.

[Marco Giustini]

Absolutely, I love the idea that I can adjust the convergence using easy to access knobs (Barco or latest Christie if not mistaken). In my experience it was normal to find a little drift on a Barco after 12 months while it was pretty unusual to find a drift on a "bolted down" model. That said, my tolerance for adjusting a drift was much larger on a machine which would require two people and several hours to attempt to adjust - while I could try to adjust a Barco by myself and it would probably take 30-45m top (less time if someone could help by the screen).

motorised panel adjustments? Wow, I have never heard of that. Could you point me to a model that does that, just out of curiosity?

BTW: has TI fixed the issue with ringing when using digital convergence? We were told not to use it years ago, I never seen a bulletin stating the opposite

[Steve Guttag]

Series 1 projectors (NC1600 is in there), often had "challenging" convergence adjustments. The processor almost always required loosening the DMD mount/formatter just enough and then using either crazy long allen driver (and I mean like over 1-foot long) or special tools that threaded in/stuck out far enough to reach. Then it was a process in frustration to tighten up the DMD mount without causing it to drift some and possibly "pre compensating" for that. The DMDs are placed where they optically need to be for the light path...which doesn't necessarily mean getting to the mechanical mounts/adjustments are easy. Factories can converge via fixture that we in the field don't have.

Barco at the end of S1 and into S2 used their flex-shaft system (like the old Strong X-60 lamp adjustments), also the DP100 had easy to get to convergence. The advantage there is convergence no longer requires tools...the downside is that the flex shafts store energy (back off on them once aligned) and the formatters/DMDs are never really tightened down and can/do drift. NEC, for some reason, kept with the special tool theory on their S2 (and they're pricey). One could load the NEC S2 prisms with the resquist cap screws (small, I forget the thread size off of the top of my head) and use the really long allen drivers (make sure to insulate them or you'll have a much pricier repair bill as you WILL short things out). The advantage of loading in cap screws into the prism is not having to remove them. On the NEC...you have to lock things down REAL GOOD before unscrewing the tools and you MUST have three minimum and 6 preferred. Once you loosen the formatter/DMD locking screws, it is spring loaded and WILL jump out of alignment. If you load the adjustment screws in there, it can't jump far. Oddly, the larger NEC S2 do keep screws in...it is just the 1200/2000 that have the "special" situation of no adjusters on-board.

Since I have not worked with the NC1600, I cannot comment on its adjustment but I suspect that it is VERY similar to the NC1200/2000 though you may have to contort yourself more to get at everything. Nobody really got S1 convergence easy, except the DP100.

Barco, with the S4 has gone away from the flex shaft and now has a nifty gear reduction system so you can get a pretty fine adjustment but you do have to control a bit more (you win a little, lose a little but probably better over all, especially since they are 4K with very small pixel pitch).

[Mark Gulbrandsen]

To me this is a big enough reason not to ever go with an NEC, unless newer models fixed this issue.

Yes, S2 NEC is pretty easy to do as the DMD are spring loaded. You also have electronic convergence through the ICP of a few pixels either way. There are specs to torque the DMD's to in inch pounds when you are done. Consult with NEC on that spec and the proper tool.... I sold my torque kit some time back and it's been 7 years since I had to converge one.

[Steve Guttag]

I had a glance at the NC1600 service manual and it looks like the prism is identical or nearly identical to the 1200/2000 and could see the adjustment area. So yeah, you either need to invest in the adjustment tools (just so 3" or so long shoulder screws with a VERY long shoulder and knurled end) get some cap screws and the long allen drivers with insulated shanks. It will not be fun but it is doable (and would be much easier if the USL VCC was still available).