Film-Tech Forum ARCHIVE: NEC 2000 POWER SUPPLY PROBLEM ?

This is topic NEC 2000 POWER SUPPLY PROBLEM ? in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by David J Hilsgen (Member # 2614) on 09-19-2018, 03:19 AM:

I have one that blows the internal cartridge fuse on that circuit board inside, it will work for a while before it blows .all connections seem good.

Posted by Leo Enticknap (Member # 534) on 09-19-2018, 06:06 AM:

Projector (card cage) power supply or lamp power supply?

Posted by David J Hilsgen (Member # 2614) on 09-19-2018, 01:19 PM:

It's the one for the lamp

Posted by Mark Gulbrandsen (Member # 72) on 09-19-2018, 04:48 PM:

I'd be placing a DC amprobe on the lamp positive to see what the real lamp operating current is rnning at. Because the fuse blows after a delay it is likely running slightly too high and the fuse eventually gives out. If it is running at too high of current it could be a serial control issue or a bad rectifier. Out of over 275 NC-2000's that I installed I never had a rectifier fail. But I have had rectifier failures in early NC-1200's.

Mark

Posted by Leo Enticknap (Member # 534) on 09-19-2018, 06:25 PM:

Try pulling a log and looking at the LPSU output voltage history. Is there a spike at around the times the fuses blew?

Another possibility is a bad lamp. If you have a "used but OK" one lying around, swapping it in costs nothing to try, and might just help you to isolate the problem.

Agreed with Mark, though - the LPSUs on Series 2 NEC xenons tend to be pretty reliable. In fact, the only power supply-related parts I've seen die on NECs on a regular basis are the NC900 ballasts. These burn out so frequently that I'd advise any theater running these projectors to consider keeping a spare in stock.

Posted by Steve Guttag (Member # 268) on 09-20-2018, 12:32 AM:

I've had LPSUs go on both the 1200 and 2000 though the 2000 are more rare. In each case, I've had to change the igniter too because the igniter and LPSU manufacturers have to match. That said, most of those were circa 2012 units. All were in warranty and I haven't had any go since.

As for NC900 ballasts...they don't seem to go of their own accord but during lamp failure. But with version 6 and 7 of the lamps, they are now finally getting to the 3000 hour mark more often than not.

Posted by Mark Gulbrandsen (Member # 72) on 09-20-2018, 02:31 PM:

Yea, on the 900's when lamps explode sometimes the electrodes manage to touch together briefly and that blows the board out.

Mark

Posted by Leo Enticknap (Member # 534) on 09-20-2018, 05:20 PM:

I was told that when you replace a ballast, you must replace the lamp it powers along with it. Presumably that's the reason why: if the lamp has failed in a shorted state, then if you replace the ballast with that lamp still installed, you'll fry the new ballast.

One of the ballast/lamp combos I replaced included a lamp that had done 5,200 hours (and I think that must be genuine, because the hours are stored on the lamp info chip: it's not like they forgot to reset the timer), and so I think that can probably be blamed on the bulb. The others were all with lamps that were well within warranty hours, though. The only common factor I noticed was overheating: two of the affected projectors were in rabbit hutch enclosures in Bel-Air Circuit homes with inadequate ventilation, and the others were in booths that seemed really hot to me. The temperature data in the logs looked gnarly, to put it mildly.

Posted by David J Hilsgen (Member # 2614) on 09-20-2018, 09:42 PM:

Thanks for the info