Film-Tech Forum ARCHIVE: NEC 2000 possible PSU Issue

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Posted by Stephen Frazza (Member # 2320) on 03-15-2014, 05:15 PM:

I have a NEC 2000 using 2000W bulbs.
I noticed the picture has gotten dim so I took out a bulb with about 1000 hours on it.
I then put a brand new bulb in and had the same issue.

I then noticed in the DCC (pics below) that at 75% it was maxed out at 85 Amps but I was only seeing around 1500 Watts.

I checked the voltage at the panel and at the projector and I was seeing 110 across each 205 across both. The same as another similar setup without issues running off the same panel.

I tried a new breaker and even put it in a different spot in the panel just to be sure. It didn't help the issue.

I am including 2 pics below of the DCC. the first of the problem one and the second of the one without issues on the same panel.

I am thinking it is the PSU. Is there anything else I can check or try to fix this.

Thanks

Posted by Mark Gulbrandsen (Member # 72) on 03-15-2014, 06:15 PM:

Have you checked the error logs yet? Possibly a bad PSU but could also be a CPU error as the CPU controls the PSU via a serial linky. I hope you're NOT using OSRAM lamps, if you are I would immediately first suspect the lamps are bad. I have had issues with but one PSU but it was a brand new out of the box 7kw unit for an NC-3240 that acted temperamentally.

Changing the PSU is not difficult but swapping the CPU module is a lot easier and I would do that first just to rule it out. You'll spend more time swapping the PSU out than the CPU (top module in card cage). So if you have more than one projector in a multiplex you can do some swapping to see what's up. If you are a single screen then NEC and Strong both have toll free numbers you can call for Technical assistance.

Mark

Posted by Stefan Vogels (Member # 5573) on 03-15-2014, 08:52 PM:

Could you include pictures of the information tabs for both projectors ?

Posted by Steve Guttag (Member # 268) on 03-16-2014, 07:24 AM:

The thing is...the LPSU is showing that it is outputting 84.9A (out of 85). But only about 1500 watts...implying that the voltage is low. NEC does not display voltage but it is implied in the wattage...the voltage is likely around 17.6V. This could be due to the lamp or the LPSU. NEC does not have one specify the voltage max for a lamp...just the wattage max and the current max so I would think it does not have voltage regulation...just current and overall wattage. If that is the case, then it is the lamp or the specification in the projector was accidentally set to 1500-watts rather than 2000 or whatever the actual specification is.

I'm going with the lamp and then the LPSU (not able to put out the right voltage for the lamp)...particularly if the lamp isn't an Ushio.

Posted by Marco Giustini (Member # 4544) on 03-16-2014, 07:25 AM:

The wattage depends on the voltage. You may have a lamp which is running at a slightly lower voltage, hence a slightly lower wattage. Check the lamp's specifications, they should contain a range of acceptable voltages.
I'd say if the amps are ok, there's nothing wrong with the PSU, but you should check on the actual cables (and you must not do that unless you know what you're doing, there are fatal currents there!).
Do you have a light metre? Did you align the lamp when you replaced it? On NEC you should check the peak metre, then look at the screen and optimise the light the old fashion way, the metre is not accurate - by far.

Posted by Stephen Frazza (Member # 2320) on 03-16-2014, 10:25 AM:

Yes they are both Osram bulbs but,
the problem happened suddenly on a bulb that had 1000 hours on it and then also on the brand new bulb that I put in. I will try another bulb but I don't think its that.

I have 7 of these NEC's and have always used the same 2000W Osram bulbs without problems.

As to it being set to 1500W instead of 2000W, I'm not sure where this is set in a NEC, but I do doubt that any settings were changed because I would be the only one to have been in there to do it.

I understand that the wattage is implying low voltage that is why I tested it out the panel and at the projector going into the PSU and it was ok.

I did look at the alignment but even after adjustment it is still dim as I do not think that was the problem because of the low wattage.

I have also checked the logs and there isn't any error showing.

So I guess the next steps would be another bulb and then try swapping out the card and then the PSU like Mark suggested.

Posted by Mark Gulbrandsen (Member # 72) on 03-16-2014, 11:59 AM:

I would absolutely suspect the Osrams first and foremost... PERIOD! I too was selling and installing Osram's in my customers NEC's and they were failing left and right and at any random time in the 2400 hour period. Ditto for LTI Helios which I was using early on while waiting for the Osram 2kw to be available. I finally gave up on both of them because they were so unpredictable and the few dollars saved is then lost after the first failure and shows lost. I mean the difference between Ushio and Osram is not very much. The Helios would almost always loose a seal which is a pretty dangerous failure mode in itself. I switched to only selling Ushio and will remain that way. I think you'll find many other tech's here that have been on the Osram boat and jumped off just before it capsized.

Beyond that the CPU module then the LPSU in that order... LPSU failures are extremely rare.

Mark

Posted by Steve Guttag (Member # 268) on 03-16-2014, 02:37 PM:

By low-voltage I was referring strictly to the output of the LPSU...the voltage at the input of the projector...if it was below the range the NEC could handle would result in the entire thing not working. Even "wide-band" power supplies (which the NEC's LVPS is) typically have two operating ranges...100-140 and 200-240...not a continuos 100-240.

As for the wattage on the lamp...that is set on the "SETUP" button of the lamp page...which requires supervisor privileges, also can't be altered while the projector is out of the stand-by state (but you can view it in the operating state).

I have no problem saying that Osrams are junk...all of them and I don't normally berate equipment on this or other sites but they just plain suck. They may or may not be the cause of the problem this time but they will be part of your problem at some point, guaranteed.

So I'm sticking with a bad lamp and the LPSU...and the reason the LPSU could be the problem is if it has voltage regulation...it may have failed and is capping the voltage limit. If the gap is too wide on the lamp, you could easily get the situation you are in...low light, low voltage and the current at the max. Conversely, if the gap is too narrow, you'll get a VERY bright lamp that has voltage WAY over where it should be and will hit the maximum wattage before it hits its current limit.

Don't rule out a bad batch of lamps...particularly from Osram...they excel at bad batches.

Posted by Stephen Frazza (Member # 2320) on 03-22-2014, 06:42 PM:

Just to follow up with the resolution.

I first tried swapping bulbs with another theater and they problem stayed so I figured it wasn't the bulbs.

I then swapped the LPSU with another theater and the problem followed the LPSU, so we have ordered a new one.