I have a Samsung SyncMaster 940BW monitor. Around 4 months ago (with a graphics board upgrade) I passed from using VGA to a DVI connection.
Around a month or so, I have been hearing strange, hi-pitched sounds coming from the back of the monitor (more or less where the power cable connects to the monitor) and also a very faint burning plastic odor coming from the back.
The sounds seemed to be more audible when the monitor was off (but still connected to power) and also seemed to be in sync with the power LED at front. It also took a long time to turn on from sleep, reaching as much as 10 minutes. As of yesterday it no longer shows any image, even the test pattern.
From the information I could gather online, it seems as though the monitor reached the end of its live and/or there are some bad capacitors, although this being the first time it happened I have no way to tell. Hence I ask:
- Has my monitor "died"?
- Why does it make the hi-pitched sound I mentioned earlier?
- Would it be feasible to repair by an end user?
Best Answer
The sound is coming from the power supply of the monitor.
You say it is more audible when in stand-by and in-sync with the power LED. I have an LG monitor which does the same.
It's a power supply design issue. Most devices nowadays are using switched mode power supplies which adjust the switching frequency depending on the load (the power needed by your monitor). When in stand-by the switching frequency (which is above the human ear limit of 20 kHz) drops below this limit.
The "issue" is that this is the frequency of an electrical current and by no means you'd be able to hear it. So something must have become loose (probably the switching transformer's core or some pin of the power transistor that controls the transformer which would explain the overheating and the smell).
Power supplies of LCD monitors can be repaired/replaced if you have electronics knowledge. Most probably, there is a dry joint somewhere.
Just as a measure of safety, don't let the monitor plugged into mains even in stand-by for long times or when not using.