Reply To: Atari ST SYNC loss on demos

Total Eclipse

Adjusting the coast settings doesn’t make any difference.

By way of an experiment, I’ve connected the ST to another LCD TV that has a direct RGB SCART input. For each of the problematic demos, the TV shows the full picture, however there are definite sync issues. The Cuddly Demos fullscreen displays sync tearing at two or three points on the screen, suggesting that for some scan lines the sync pulses are out of spec compared to the rest of the screen.

Similarly the Union mainscreen is displayed correctly apart from the scanlines containing the full-width scroller, which again struggles to sync properly and has random horizontal distortion. When the OSSC tries to display this, you actually see about half the screen displayed just for a single frame, then sync is lost. I assume this is the OSSC being able to display the incoming field right up to the point of the crazy sync pulses for the scroller, at which point it can’t lock on any more.

Incidentally, connecting via a RF modulator doesn’t have any screen distortions at all.

So while it’s a little disappointing that the OSSC can’t sync in these instances, it’s not too surprising either. I’m not sure whether there are any other settings that might improve the chance of getting the OSSC to lock on to the signal? The wiki manual is great for explaining exactly what each setting does, but is there a more simplistic guide to tweaking?