Video quality revisit
Posted: Sat Jun 06, 2020 10:27 am
Hi,
A few months ago I posted about my dragon behaving poorly with a cheap composite to hdmi converter. I eventually switched out the converter for a different one after testing the machine with a TV that had proper composite in, moved on to sorting out other bits of the machine. The new adapter was by no means perfect (flickering occasionally, green periodically looking washed out), but I decided I could live with it.
Since then I've done some more work on the machine, recapped it, got a CocoSDC and adapted a joystick to work with it. The latter means I've been trying more games and running the machine in graphics modes more often. This has now shown up that in 4 colour Green, Yellow, Blue, Red mode the blue and red seem to be nearly indistinguishable. This also seem to be the case when connecting it to the decent TV, which also shows a lot of 'shimmer' when there are bands of red and green. Fiddling with RV1 allows some tuning of picture stability but doesn't seem to help with the colour issue. This is a later rev board without RV2.
I'm not sure where to concentrate further troubleshooting efforts, and I only have limited tools at my disposal (multimeter primarily). Sugegstions welcome.
Stu
A few months ago I posted about my dragon behaving poorly with a cheap composite to hdmi converter. I eventually switched out the converter for a different one after testing the machine with a TV that had proper composite in, moved on to sorting out other bits of the machine. The new adapter was by no means perfect (flickering occasionally, green periodically looking washed out), but I decided I could live with it.
Since then I've done some more work on the machine, recapped it, got a CocoSDC and adapted a joystick to work with it. The latter means I've been trying more games and running the machine in graphics modes more often. This has now shown up that in 4 colour Green, Yellow, Blue, Red mode the blue and red seem to be nearly indistinguishable. This also seem to be the case when connecting it to the decent TV, which also shows a lot of 'shimmer' when there are bands of red and green. Fiddling with RV1 allows some tuning of picture stability but doesn't seem to help with the colour issue. This is a later rev board without RV2.
I'm not sure where to concentrate further troubleshooting efforts, and I only have limited tools at my disposal (multimeter primarily). Sugegstions welcome.
Stu