One of my older prototypes for Super OSD always had one little bug. A single pixel in the video, about midway in the frame would always be off. It did not really affect anything as most pixels normally stayed in the off mode, but it was noticeable during test patterns. I could never narrow down what the cause was.
Thinking about it now, could it have been a failed bit in the memory array? Is this at all common with MCU's with SRAM? The prototype was not abused: a fixed +3.38V (within the rated 3.0V - 3.6V), room temperature operation, minimal load on the outputs. It was a dsPIC33FJ128GP802.
I'm designing a new prototype now and I think it's the same chip as I used last time, so I will see if the problem occurs again. Does anyone know if it is prudent to run a "memory test" on a chip?