Film-Tech Forum ARCHIVE: NEC 1200 LPSU Error

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Posted by Chris Daigle (Member # 7347) on 04-07-2015, 06:16 PM:

I'm hoping someone can shed some light on this problem. Earlier today, we had a projector (NEC 1200) shut down on us with the message: "ERROR!! LPSU OVER TEMP". Over the last several years I've had a couple of LPSU FAIL error messages which resulted in the purchase of new power supplies, but we haven't seen the Over Temp message. The booth itself is not hot, about 68 degrees F and there is plenty of exhaust on the projector and the filters are all changed regularly. I actually removed the power supply itself a short time ago and replaced the two rear 24v fans with two newer ones from a spare unit we have, but when I put it all back in and turned on the projector, within a couple of seconds it comes back with the same error. After being totally off for several hours, I know that the unit itself is not hot, but is there some kind of a reset procedure on the projector to turn off the error, or am I looking at yet another new power supply purchase?

Posted by Steve Guttag (Member # 268) on 04-07-2015, 07:23 PM:

So is it an intake Temperature problem or internal to the LPSU? You can use the DCC to see what the projector thinks the temp is. INFO>LOG>System Status. You can also look at the Temperature log to see if it has been rising.

I don't think you can get the LPSU to give its own temperature status...it may just be the LPSU merely complaining and not giving any reason other than a sensor says so. That is, it could be a sensor failure or the control system within the LPSU sending out incorrect information. Or it could be the projector's sensor that has an issue. The thing to start with is to see if the projector itself thinks the temp is too hot and see if the sensor's reading seems way off (compare it to another projector).

Posted by Gordon McLeod (Member # 33) on 04-08-2015, 03:12 PM:

we have had several of them fail in that mode reporting that even with the lamp off
Unless you are a theatre in Japan NEC will not fix the power supplies and the manufacturer Rubicon will not release any service info on them

Posted by Mark Gulbrandsen (Member # 72) on 04-09-2015, 05:42 PM:

I always felt the NC-1200's were the best reason to actually buy the NC-2000! I had one NC-1200 power supply fail under warranty but it was replaced pronto. I only have about a half dozen NC-1200's in service. The NC-2000 has a better supply made by Sanrex.

Mark

Posted by Chris Daigle (Member # 7347) on 04-09-2015, 07:18 PM:

Our tech showed up to diagnose this problem and apparently, for the "LPSU Over Temp" error on the 1200, there was a relatively easy (and inexpensive!) fix. He ended up having to snip the red wire on the ribbon cable inside the power supply. Not sure what that controls, but he simply cut it, re-installed it and the issue went away.

Posted by Steve Guttag (Member # 268) on 04-10-2015, 05:55 AM:

No doubt...it is related to the temp sensor in the power supply itself. It is good to know about the red wire.

As a percentage, I think our NC2000 LPSU are equally problematic though not horribly so. NEC has also switched the NC1200 LPSU and Igniter to Sanrex. Thus far, our power supply failures are actual failures...they are dead as a door nail.

Posted by Marcel Birgelen (Member # 6801) on 04-10-2015, 06:58 AM:

I'll guess the red wire will be the signalling cable for the temperature sensor? [Smile]

The problem with this hack is obviously that you will now not be warned about any REAL temperature problems inside the PSU itself. If it's just the temperature sensor at fault here and not a controller behind it, wouldn't it make sense to just solder a new one in place for a few cents?

Posted by Marco Giustini (Member # 4544) on 04-10-2015, 08:01 AM:

Reminds me of Homer Simpson covering the 'check engine' warning light with a piece of tape.