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Strange buzzing from LCD monitor

F

Franc Zabkar

Jan 1, 1970
0
If I use Windows Notepad to view a text file consisting of the letter
"a" repeated ad infinitum, my Mitsubishi Diamond View DV152 15" LCD
monitor buzzes noticeably. The same buzzing occurs with other
repetitive patterns. I have noticed that bold face type is louder, and
that shrinking the notepad window progressively reduces the sound
intensity. I wonder if this is normal, or is a sign of impending
problems with the inverter or power supply.


- Franc Zabkar
 
A

Art

Jan 1, 1970
0
Possible noise from the power supply when the load is increased. Does the
noise come specifically from the lit display, from the base, or rear of the
unit?? May want to try an place the unit on a soft surface such as a mouse
pad and see if the noise is mitigated??
 
F

Franc Zabkar

Jan 1, 1970
0
Possible noise from the power supply when the load is increased.

I notice that the noise does not change if I press the "Auto" button
on the monitor. This blanks the screen and brings up a small
calibration message box at the centre. It appears that the noise is
related to the video content in the signal, not to the actual screen
display.
Does the
noise come specifically from the lit display, from the base, or rear of the
unit?? May want to try an place the unit on a soft surface such as a mouse
pad and see if the noise is mitigated??

I didn't realise it before, but the noise comes from the monitor's
built-in speakers. Adjusting the volume setting alters the sound
intensity. Very strange!



- Franc Zabkar
 
J

James Sweet

Jan 1, 1970
0
Franc Zabkar said:
I notice that the noise does not change if I press the "Auto" button
on the monitor. This blanks the screen and brings up a small
calibration message box at the centre. It appears that the noise is
related to the video content in the signal, not to the actual screen
display.


I didn't realise it before, but the noise comes from the monitor's
built-in speakers. Adjusting the volume setting alters the sound
intensity. Very strange!
Perhaps a bad capacitor in the power supply is allowing excessive ripple
into the voltage to the audio amp.
 
A

amstereo

Jan 1, 1970
0
LCD's have shit amps for the speakers. (they pick up way too many RF
signals.
 
T

Tim Mitchell

Jan 1, 1970
0
Franc Zabkar said:
I notice that the noise does not change if I press the "Auto" button
on the monitor. This blanks the screen and brings up a small
calibration message box at the centre. It appears that the noise is
related to the video content in the signal, not to the actual screen
display.


I didn't realise it before, but the noise comes from the monitor's
built-in speakers. Adjusting the volume setting alters the sound
intensity. Very strange!
It must be the audio amp picking up interference from the VGA cable,
when your video signal has lots of transitions from black to white.
Probably down to bad screening inside the unit or interference getting
through on the power supply to the audio amp. Solution: use some
external speakers.
 
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