I have a Samsung Sync Master 1200NF monitor that has been working flawlessly until a couple of days ago.
A few days ago, I noticed that as I moved the mouse to wake the machine from standby mode, the monitor made some surge electrical noises in the back, similar to a loud degaussing followed by pops and cracks (Not the normal noises). I thought this was not good, the monitor synchronized and gave the usual high res, crisp and clear image after all that noise no problems.
Once again, a couple of days ago did the same thing in the morning, when waking up the machine from standby (monitor is scheduled to standby after 30 mins of inactivity), loud pops and the clicking sound of the monitor trying to sync, and it did sync, No problems.
Then at night, I shook the mouse / hit the space bar in the keyboard to wake the machine, and this time the popping, clicking and degaussing sound combined were much louder and this time there was no picture.
The green LED in the front Blinks steadily approximately one second on, one second off, but no picture, no syncing noises, no clicking, nothing.
I unplugged the monitor from the video card to run the self-test, and there is no response at all. (It is supposed to give me an image of the color bars and the connection type (Dsub - BNC)), the monitor is unresponsive now, the USB hubs / connection are working just fine and it seems it is the only thing working out of the monitor. So now, I have an 86-pound USB hub on my desk.
Any ideas, help?
This sounds like FBT T501 failure, the popping/cracking sound is due to the EHT arcing, because of overshoot on start up. The problem is caused by the FBT T501 internal capacitor having gone low in value.
The capacitor is used as part of the EHT feedback compensation loop.
It has either killed Q524 the EHT transistor or some other component due to the arcing.