Please register or login. There are 0 registered and 722 anonymous users currently online. Current bandwidth usage: 326.30 kbit/s June 30 - 11:53am EDT 
Hardware Analysis
Forums Product Prices

  Latest Topics 

More >>


  You Are Here: 
/ Forums / Monitors /

  Monitor makes constant screeching; changes with brightness of screen image. 
 Date Written 
Nathan Daniels Aug 25, 2011, 02:00pm EDT Report Abuse
I have an LCD monitor that works just fine but has recently started making a very high pitched electrical-sounding screech at all times. I noticed the noise gets lower pitched with darker images on the screen (such as a full screen command prompt) and higher pitched with brighter images (such as this website.) Now the sound isn't terribly loud or annoying but I just wanted to know if it could be a sign of something wrong. I have the refresh rate at the default 60Hz and no crazy settings. The monitor brand is Sceptre.

"The more we sweat in peace, the less we bleed in war."
Want to enjoy fewer advertisements and more features? Click here to become a Hardware Analysis registered user.
micro Aug 25, 2011, 03:17pm EDT Report Abuse
>> Re: Monitor makes constant screeching; changes with brightness of screen image.
You are either having a problem with the monitors power supply, or a very noisy electrical line.

If it is your power supply, i can't tell you what is wrong with it, or even how long it will last.
If it is your AC power into your house, a good quality line cleaner should fix the problem. Most of these are made for home theatre systems. I know Monster cable makes one. This indicates that there is a problem with your electrical service such as a place where the electricity is arcing to ground somewhere, not necessarily in your house, but anywhere in your neighborhood.

He is my previous post about almost the same problem, though yours seems worse:

I have also heard of some lcd tv's doing this, there problem was bad capacitors on their power supply.
Here is my post on having and fixing this problem my self:

GA-Z68X-UD3H-B3, 2600k @ 4.0
16 gig Corsair Vengeance
Evga gtx 260 216, samsung 2253lw"
Baracuda 7,200.12 CoolerMaster 212 +
Win 7 64, fsp fx700-gln, Razer DA,G15
Evil is powerless if the good are unafraid
Silence in the face of evil is it's self Ev
Nathan Daniels Aug 25, 2011, 03:55pm EDT Report Abuse
>> Re: Monitor makes constant screeching; changes with brightness of screen image.
Thanks for your helpful reply. If power could be causing it, there are a few more variables to add. The monitor is hooked up to a UPS which is hooked up to the wall. I get networking in this room via powerline networking but wouldn't the UPS block any sort of fluctuation in the power stream? The problem isn't bad enough to warrant me buying something made by Monster cables nor to get a new monitor unless this one actually dies.

"The more we sweat in peace, the less we bleed in war."
john albrich Aug 25, 2011, 04:35pm EDT Report Abuse
>> Re: Monitor makes constant screeching; changes with brightness of screen image.

If you do decide to replaced your cables for any reason...Monster Cables empty your pockets when far less expensive cables will work just as well in terms of video and audio quality and distance. Just get them from a reputable company and don't go for the cheapest you can find. Look for the better wire-gauge, shielding, and insulation specs.

Also, make sure your cables match the HDMI specification requirements for your card and display. Unfortunately, last rule I read stated that cable manufacturers per their license are not allowed to stipulate which spec (e.g. 1.3a, 1.4, etc) they meet, so they have to use other words like specifying the frequency the cables support, that they support the data channel, etc. Although some mfgs have slipped in spec numbers from time to time.

Same goes for HDMI switch boxes and Home Theatre Receiver HDMI I/O.

john albrich Aug 25, 2011, 04:55pm EDT Report Abuse
>> Re: Monitor makes constant screeching; changes with brightness of screen image.

Re: the source and cause of the screeching sound, I agree with micro. It's most likely the display's main power supply.

In general a screeching power supply is a sign that it is being over-loaded. Either because the load has increased for some reason, or the PSU itself has been degraded (e.g. a capacitor has failed or is failing/has changed value over time) and can no longer support its specified load.

If you have a non-LED display...

Whether the power supply is internal or an external brick the source of the noise can be the inverter power circuit for the cold-cathode lamps but the cause can be an unstable display power supply.

However, if the display power supply is an external brick (and it's not the source of the screeching) and you have a non-LED display, than it's most likely the high-voltage inverter circuits for the cold-cathode lamps that are making the sound...but still can be caused by an unstable display power supply.



  Topic Tools 
RSS UpdatesRSS Updates

  Related Articles 

A weekly newsletter featuring an editorial and a roundup of the latest articles, news and other interesting topics.

Please enter your email address below and click Subscribe.