I've just had a problem with an LCD monitor, but this question is not about solving this problem. Google did that. I want to know what is happening at the electronic and physical level. Google didn't do that. The problem:
LG Flatron W1943C LCD monitor. Most likely backlit by CCFT. It was manufacturer in September 2011, and I think that's about the time I bought it. Today, I noticed the whole screen flickering at times, which meant the backlight was flickering. Tonight, a black right rectangle appeared in the upper left corner of the screen. The diagonal of the rectangle mixed gradually with the image. The area was much hotter than the rest of the monitor. There was a hissing sound coming from the area. Lowering brightness and contrast had no effect.
The problem is well known and Google offers several ways to fix it yourself, and it's either the CCFT or the inverter, which feeds the CCFT with high voltage. The area around the connectors may be severely damaged by the heat.
But what I want to know is what is happening exactly. If the CCFT is not working properly, why a black rectangle in a corner of the screen? I could theorize it has to do with that area being the last indices of the horizontal and vertical arrays of input, but that's a digital problem. That's why I'm so curious about this matter. This theory makes more sense if you consider some of the cases found in Google that shows a crisp diagonal of the triangle, down to the pixels.
And now a more out of topic question: is this a standard time for this problem to appear?
I'm a Computer Engineering student, so I have some knowledge of several areas of physics, electricity, electronics and computing.
Thanks in advance.