UPS monitor buzzz
When my new UPS is in battery mode and my monitor is plugged into it it buzzes like a mad bee! I'm just wondering if this is normal with a ups or occasional or rare. To make sure this is clear, the monitor buzzes. It also shows a few horizontal lines that move slowly down the screen sort of like a normal tv with bunny ears. I am running with large crt monitors.
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What is the VA and Watt capacity?
Also what make and model monitors do you have? (I assume you are running 2)
I have a feeling your UPS is not strong enough to handle the load of the monitors. I would like to check the models out first though before I confirm that.
An easy test for you to do is to run only one of them through the UPS and see if that solves the problem.
Computer: negligable because monitor buzzes when computer is unplugged
Monitor: 19" CRT - Samsung SyncMaster 955DF
That's one sweet UPS you have there and is plenty powerful to run multiple monitors.
Your UPS produces a modified or stepped-approximated sine wave, which is different to the pure sine wave you get from the national power grid and is not as clean. I noticed that your monitor is quite an old model and I can only assume that the capacitors in the monitor are beginning to weaken and are not filtering the 'noise' of the output signal as effectively as it should or it never had the built in circuitry back then to handle it.
I'm guessing it's time for a monitor upgrade
NEVA!!! That thing is as bright as the day I bought it and just as clear! ~In my opinion, way better than any display model I see at the store, both lcd and those last few cheapie crts. And anyway, I'm not TOO worried about the monitor thing, it works fine without the ups with no ringing or buzzing at all, however I did have it replaced a couple years ago because my first one was ringing on the tones that nobody could hear but me, and it was driving me crazy.
I however am worried that it was not supplying good power, or that it could damage the monitor, or computer for that matter. Using the old killawatt I was getting 120.0v 59.9hz throughout my entire home last I checked, but with the ups it was down to about 112v, not something I liked, considering the box is talking about "conditioning" and "improving" the regular utility power. Do you think a lot of monitors would act better with this ups? Excuse my laziness to plug in another monitor, I'll get to that sometime...
That UPS should be able to handle 19" CRT monitors no problem. When you do get a chance to test it with another newer model monitor I would be very interested in knowing if it's still doing the same thing.
If so, then it could mean your UPS might have a faulty battery or component in it . The PSU in your PC may be smoothing it out which is why you not noticing any problems with the PC. If that's the case I would get that fixed real quick!
Okay, upon some further investigation...
I plugged in a Hitachi SuperScan 814 21" crt (it's old, but it was owned by an old guy so it's like new!) ~ buzz there too
I also noticed that my Antec Power supply also buzzes. This is a True Power 550w. I can't believe I didn't notice this before.
Now, because there is a certain store closing event, I obtained another ups, the APC 1100 Pro, which is quite a lot heftier. I noticed no noticable buzz with this ups with any devices. The killawatt reads about 126.5v in battery mode on this ups. Compare that to about 112v with the Conext 950va.
It seems to be related to the ups itself... Upon which I conclude is one or more of the following: Conext is cheaper, this particular model is cheaper (and it kind of is, but not too cheap), or this unit isn't perfect. I must also conclude that the APC model is better in many ways it seems, but it still is not perfect, giving off over-voltage power in battery mode. I should also point out that with both of these UPSs the voltage when utility power is on is only about 118.9v, vs 120.0 I get from the wall outlet, per killawatt readings.
I have one no-name brand UPS that hasn't even got the specs and rating labeled on the unit except to say it's a 600VA and the maximum input allowable is 4A. Even that one doesn't cause my PC and monitor to buzz although it gives off a slight buzz itself when it's on batteries (which is understandable as it's always working to it's maximum capacity)
No matter what brand it is, it should still do the job it was rated to do. That UPS of yours is definitely up to the job. I would get it checked out!
The 1V drop in power you experiencing is neither here or there. You'd be amazed at just how high and low the voltage fluctuates from the mains.
Most electronic components are able to handle these fluctuations so we never notice them.