I came across multiple computer displays (computer monitors) that had strange noise emanating from the back of it.
The noise is high pitched and often people might not hear it at all. It resembles a high pitch buzz, high pitch humming or high pitch sizzling.
The problem, I believe, is because of the monitor power supply which is faulty somehow or became faulty over time and this is the culprit.
Often it is fixed by raising the Brightness setting to 100%. However, one of my displays (I have three) is showing the same symptoms even when he is on stand by.
Any idea on how to fix or what to do with this would be appreciated.
Open it up, check capacitors to see if they're swollen or not, get an esr meter and check the capacitors even if they're not visually faulty..
if that still doesn't fix it sound may come from inductors... get electric grade silicon and put some on inductors (coils of wire around a magnetic material - as electricity moves through the wire shrinks and expands around the material making sound)
If that still doesn't fix it, the fluorescent lights (if the monitor uses fluorescent and not led) may be old and use more current than new lamps so the power supply now works harder to output that current - switching power supplies will change the frequency of operation and that new frequency may go into the audible range.