I noticed the screen only died when playing videos and always died at the same point if I rewatched a video. Notably, greyscale videos never caused the issue. Then I went through a video frame by frame to get to the frame it died on. Then I erased parts of the frame to find which part caused it. Eventually I found that if the red or blue pixel in the 481st column and the green pixel in the 482nd column have a difference of brightness of too much, and neither are 255 or 0, the screen dies.
I'm pretty sure the problem is the column drivers (which put data onto the column lines). They take in serial data, and my 1920 screen has 4 column drivers, each responsible for 480 columns, so the 481st pixel is the first column that the 2nd column driver deals with.
It uses more power during the row sync pulse (because it has to drive all the column lines to the correct voltages for whatever is being displayed). It uses more power for grey values (because 255 or 0 are solid on or off, while mid values are typically dithered, wasting energy in the column capacitance). I would guess all these worst-case events for power consumption within the column driver, combined with probably 'barely passing qa' silicon, means that in edge cases the power sags, something gets reset, and the whole screen fails.
So my fix is a shader to make sure the worst case conditions can never happen all at once. Visually, it isn't really noticeable. And with more work it could probably be turned into something that could be shipped to customers (within the GPU driver) without any customer complaining (for example if you are a laptop manufacturer who has purchased millions of screens with this fault).
I did consider replacing the screen, but the only source I could find was China with 60 day delivery by boat, and I decided to find a workaround till the screen arrived... The screens now arrived, but the workaround is so good I can't be bothered to fit it.
It’d be wonderful if we were in a world where working things like this out was worthwhile. I shudder to think how many perfectly working monitors are dumped each year, let alone ones with problems like this.
It's likely one of the power bond wires from the glass screen to the silicon IC. Without equipment stretching into the millions of dollars, you won't be fixing that.
Why would that cause a current-dependent symptom? Do they rely on a lot of parallel bond wires? If so, breaking one isn't realistically going to do anything.
I'm pretty sure the problem is the column drivers (which put data onto the column lines). They take in serial data, and my 1920 screen has 4 column drivers, each responsible for 480 columns, so the 481st pixel is the first column that the 2nd column driver deals with.
It uses more power during the row sync pulse (because it has to drive all the column lines to the correct voltages for whatever is being displayed). It uses more power for grey values (because 255 or 0 are solid on or off, while mid values are typically dithered, wasting energy in the column capacitance). I would guess all these worst-case events for power consumption within the column driver, combined with probably 'barely passing qa' silicon, means that in edge cases the power sags, something gets reset, and the whole screen fails.
So my fix is a shader to make sure the worst case conditions can never happen all at once. Visually, it isn't really noticeable. And with more work it could probably be turned into something that could be shipped to customers (within the GPU driver) without any customer complaining (for example if you are a laptop manufacturer who has purchased millions of screens with this fault).