I have a weird problem where I don't get any analogue video from some cores. I have a MisterPi with the IO board, using a DE15 to 5xBNC cable.
Specifically, I am having problems with the PCXT and Tandy CoCo 3 cores.
I have a PVM-2950QM connected, and every other core either works flawlessly, or shows a scrambled image (due to not being 15kHz, which is expected).
But for the 2 above cores, I get nothing.
Is there rhyme/reason to this? I can see comments in PCXT's source code saying "force scandouble", which I thought at first may be a clue, but I would expect that I should still see an un-synced image, as I get with, say, ao486. Also, I messed with modelines, and while these affected the output on HDMI, I still had no image on analogue.
Tandy CoCo 3 is especially strange, since CoCo 2 works just fine.
What am I missing here?