Quote:
Originally Posted by jarp
Hold on, it just got better. I suspected that maybe my SCART lead does not offer perfect sync signal for the OSSC since some of the modes partially worked after I enabled aggressive sync LPF from the OSSC. SCART uses composite sync where both hsync and vsync signals are transmitted via the same conductor. Also my Amiga-SCART adapter uses resistor to approximately match TTL-level voltage of Amiga's composite sync to voltage expected by SCART.
So curious I was and I just soldered buffered VGA adapter for my Amiga where hsync vsync are transmitted separately and BOOM. The OSSC now syncs to every mode short of A2024 and Euro36. Also my monitor is able to sync every mode. Woohoo what a difference.
I don't have an oscilloscope at hand but I suspect that either Amiga's composite sync is dirty or resistor messes up voltages too much. VGA fixes everything.
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Apologies for digging up an old thread but I recently purchased an OSSC and although it works brilliantly I'd like to access some of the other screen modes. A search revealed your post above and I wondered if you could give me some more details about exactly what modification you made to improve the sync?