NEC 2490 Buzzing/Humming?

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soujir0u

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Aug 14, 2008
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Hi, long time lurker, first time poster here.

I recently purchased an NEC MultiSync LCD2490WUXi monitor here in Australia. The manufacturing date is 2008/06.

The screen itself looks fantasic. The only problem is that there's an audible high pitch hum/buzz coming from the screen, probably the backlight.

Has anyone else encountered this? Is this normal or do I have a problematic sample?

Thanks.
 
I have a slight hum/buzz with my 2690. Apparantly it is inaudible in countries that use 110V electricity like the USA. Those of us with 230/240V supplies may have to put up with a hum/buzz.
 
My LCD2690 does not do this, but I'm in Canada > 110V as well. I only hear a very quiet click when it turns on or comes out of power save.
 
My 2690 has a little buzz too. I don't hear it when I sitting in front of the panel unless I put my ear on the display. The manufacturing date is 2008/05. Anyone else has the same issue with NEC 2490/2690 displays ? Is this a norm for NEC displays ?
 
My 2690 buzzes too. But I practically ignore it now.
I agree that it is related to 220 V.
 
Wow, that's a shame for a monitor of this price.

Judging from the labels at the back the monitor should have a universal power supply. Can someone confirm this?

I might try using a 110V transformer that I have and see if it really solves the problem.
 
Yes, it is a shame. The monitor also produces another sound when I set the brightness over 25 %.
 
Yeah, it seems like it produces 2 different noises. One is a hum and the other is an 'electrical' buzzing sound.

I just tried it on 110V and the buzzing is gone. The hum, however, remains. Sounds like I have to live with it. :(
 
soujir0u said:
Yeah, it seems like it produces 2 different noises. One is a hum and the other is an 'electrical' buzzing sound.

I just tried it on 110V and the buzzing is gone. The hum, however, remains. Sounds like I have to live with it. :(
Click to expand...

Thanks for the test. I don't have problem with "buzz", since my brighness is 20 %. Too bad the transofrmator does not make "humm" go away.
 
It's disappointing that NEC displays still buzz and hum. I have an early (European) 2690 which went in to NEC for "the fix" (see earlier exchanges for background to the 2690 buzz problem). This did not work and the buzz and hum (for both are present) are if anything worse.

I wish I could find a 26", or 27" or 30" lcd display that provides good IQ and sRGB (through native gamut, hardware calibration or factory setting) that definitely does not hum.
 
I think many larger monitors are plagued by various sound related problems, not only NEC :(
 
I sent the monitor back for repair and they replaced the power supply. It's a bit quieter now but I can still hear the hum. It doesn't fluctuate with the brightness now though.

Another problem I sent it back for was that there was (and still is) a particle stuck inside the panel, which they didn't fix. It's causing a shadow on the screen about 2 x 2 pixels and is rather annoying. It's just as bad as dead pixels. Wonder if I should bother sending it back again. Sigh...
 
soujir0u said:
I sent the monitor back for repair and they replaced the power supply. It's a bit quieter now but I can still hear the hum. It doesn't fluctuate with the brightness now though.

Another problem I sent it back for was that there was (and still is) a particle stuck inside the panel, which they didn't fix. It's causing a shadow on the screen about 2 x 2 pixels and is rather annoying. It's just as bad as dead pixels. Wonder if I should bother sending it back again. Sigh...
Click to expand...

Did you mention to them the problem about the particle? If so, then you should send them the monitor back and let them pay the postage.
 
Yup, I did tell them about it. This time I'll send them a photo with an arrow pointing to the problem. :D
 
Has anyone been able to collate information, in tabular form, which shows which NEC2690 revisions have the hum/buzz issue? I have seen a lot of reference to various european revisions such as 4A, 4B, 4F.

I have just bought a NEC2690 and my monitor is labelled revision 1A manufactured 2008/08 with a serial that starts 881...

I am located in the UK. The monitor box says - "assembled in the EU" and the name of "TVP displays - poland"

I am amazed that my monitor is revision 1A at roughly 18 months since the monitor was first released. Should I read anything into this revision number? Is it a repaired early unit maybe? Or do they restart the revision numbering at the start of each year? Any thoughts?

It certainly has no dead pixels and performs well on all lagom.nl LCD tests.

I do experience the infamous hum and it appears to be related to the brightness setting.
I find it worst from brightness 0-25 and from brightness 75-100. from about 25-75 it is less noticable. Does this tie in with others experience?
 
An update on the buzz/hum on my NEC2690. I followed soujir0u's idea and got a transformer to test the monitor at 110v. In my case it made no difference to the hum/buzz - it was still there. I can only conclude that the buzz/hum is related to the backlight. (When my ear is pressed near the side of the frame at ANY place I can hear this buzz/hum distinctly from within - like a fly or a bee The backlight is shown to be the source of the problem by the fact that when I change the brightness level the hum/buzz changes in pitch and amplitude. Its a real shame these monitors have this problem. It's clearly a design flaw. I know the HP2475w is 1.4" smaller in diagonal but it is wide gamut and there is no hum/buzz at all so this shows they can be designed without this flaw. I wll probably go for 24" LED backlit display (there are several coming out in the near future - including the Eizo EV241W) and live with the VA colourshift - which has to be better than a constant humming/buzzing due to CCFL backlighting.
 
So I got a replacement monitor from NEC.

This one has no dead pixels or stuck particles in the screen.

<delete>It also seems to hum less than the previous one that had its power supply replaced, but fluctuates according to brightness similar to pedrito's.</delete>

Actually, I think it hums a bit more than the one that came back with a replaced power supply but hums less than the one I originally had. It does sound like its the backlight.

I guess I'll just have to live with it.
 
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