I've completely disassembled the machine, but I can't find the location of this fan. Where are the locations of fan4 and fan5? Can you help me? NEC LASER NC 1700L WhatsApp Image 2026-06-16 at 10.55.17.jpg
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In the NEC Digital Cinema Communicator app there is a fan map feature that shows you a diagram to help you to locate it (unless your projector is older than the NC900, which was the first projector they introduced it for). At an airport and don't have much time to boarding, but if no-one else has come along with the answer by tomorrow, I''ll fire up DCC in emulation mode and get some screenshots for you. -
So I emulated a stop error on fans 4 and 5 as so:
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...and then pulled up the fan map.
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Here they are:
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They are the cooling fans for the laser driver boards. Not sure how easy they are to get to: it'll depend on if they're accessible by removing the board on top of the laser driver assembly and taking off the assembly's top cover, or if you have to take the entire assembly out of the projector. To order replacements, fan 4 is part 79TPR105, and 5 is 79TPR106.Comment
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I cleaned and reinstalled fan4 and fan5, but I'm getting another error. Can you help me?
WhatsApp Image 2026-06-21 at 13.51.58.jpgComment
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By any chance, did you clean those fans with compressed air, spinning them very fast while still connected?Comment
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I’m a bit suspicious of the fact fhat both have stopped at the same time. If it were just one, then it’s likely a failed fan. If there is no dust contamination or other blockage to explain it (per Marco’s suggestion), maybe check the connections to the slave or thermal board (not sure which in that model), and then voltages?
Edit - just seen those other errors. LD version read fail suggests to me that the CPU or FMT board cannot communicate with the (or a, depending on the system architecture) laser driver board. As a first step, check that all the connections went back in the right places when reassembling: it’s very easy to miss one or two when reassembling after major surgery on an NEC. If those errors are still there after confirming that all the connections are correct, then at that point I’d suspect a bad board. I don’t know that model well enough to make a helpful guess as to which one. I think you’d need a tech who has been trained certified on that model at that point.Last edited by Leo Enticknap; 06-21-2026, 11:52 AM.Comment
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Back in the day when Steven Spielberg still made good movies, you also had the Animaniacs, which were at least, part his idea. In this show, you had a segment called "Good idea, bad idea"...
And now it's time for another Good Idea, Bad Idea:
Using your DCI projector as a wind energy farm: Bad Idea.Comment
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If it wasn’t clear I was asking Volkan if he spun those fans with compressed air to clean them while still connected. That might turn them into generators and damage the circuits they’re connected to.
fans can be cleaned with compressed air but need to be locked in place with a stick or something so they can’t spin.
and to be honest I wouldn’t use clean those fans with compressed air while mounted regardless: compressed air can and will push dust where it wouldn’t normally go.Comment
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Unless the projector ran for years without its air filters being cleaned or replaced (depending on whether wire mesh or paper filters are in use), I'd be surprised if it's significantly dirty inside. In my experience, the intake air filtration on NECs does a very good job at keeping crap out - much better than Barco or Christie.
Again, what rings an alarm bell for me is that two fans, right next to each other, appear both to have kicked the bucket simultaneously. By the same token, AFAIK, there has never been an instance of both engines on a twin engine airliner breaking down in flight separately and for totally unrelated reasons. The only documented cases of multiple engine failure in flight have all had a single, underlying cause (e.g. this one).
If it were me, I'd want to do some harder core detective work at this point. To start with, are the fans actually running when they should be? Is this a PWM problem that is causing them to be misread as stopped, rather than that they're actually stopped? If that's not it, my next step would be to identify the board and headers to which those fans are connected, and measure their output voltage. If that's OK, I'd then want to trace that wire loom from the board to the fans, to see if there is any physical damage. Then, and only then, I'd remove those fans from the laser driver assembly, power them separately, and see if they start to spin. I can't think of anything else to check.Comment
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The oil slick coming out of the corn machine has completely seeped into the machine, and all the fans are in a deplorable state.Comment
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Popcorn oil is to a digital projector, what a flock of birds is to an aircraft, only in slow-motion.
Did you manage to get your laser driver running again? Because if the general condition of the thing is that it's coated in popcorn grease, then I think that this is also just a case of bad contact. Some deep cleaning using a lot of contact cleaner will probably help.
As for those fans: In most cases it's best to simply replace them with new ones instead of trying to get the sticky oil out of all the crevices.
Do you have a booth that's open to the lobby? I know a few cinemas that were constructed this way, they simply put their projectors on an elevated platform in the lobby. When the first iteration of digital projectors came, most of them were completely done for after 5 years, even before the VPF on most of them had expired... Most of them have either closed or closed their booths from the lobby afterwards.Comment
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