Denial

[...] The only bit that doesn't make sense is that X=35 input. I've simulated this and VCNT.RESET goes high when X=35 on the LAST LINE. It doesn't make sense and clearly I have to check things over a few more times and try to work out why it doesn't reset at that point on the last line. I'm going t...

Bit late to the party. It appears the S-Video mod being talked about here takes the chroma directly off the chip, albeit with a resistor + cap in between. This does not feel right to me. Should there not be a proper buffer/amplifier in between? I.e. similar to how the C64 modulator operates.

I did an audio capture of the high score music. Here are 3 waveforms from the same sample from different VIC20s (VIC20 CR model, NTSC 'old' (2-prong power), PAL old.) vicsamples.png The NTSC old model is the clear winner here with 4 distinguishable levels corresponding to 3 voices. The other models ...

If needed I can do a new capture - in theory I could also measure the phase offset between light and dark colors with my oscilloscope, although how exactly I haven't yet found out.

The order from left to right is black / white red / light red cyan / light cyan purple / light purple green / light green blue / light blue yellow / light yellow orange / light orange so then green would be at index 8 indeed. I also notice that yellow is also very greenish (compared to light yellow....

The NTSC VIC has two variations of cyan apparently. I found this post that may be related https://www.lemon64.com/forum/viewtopic.php?p=979712 My NTSC VIC cyan looks distinctly blue so I guess this is an older variant - see images from capture card (NTSC contrast is a bit off but the color should be...

Apparently early versions of the 6560 had a different palette where cyan would look more like a light blue rather than the colors described here. (I think I may have one of these.) Could be interesting to create a variant for that too.

PAL VIC-20 is 312 lines

Re cyan being off: I seem to recall that older 6560 variations generate a different cyan that is more blue-looking. E.g. this is what my NTSC VIC20 looks like bt848_ntsc_comp_vic20-ntsc.png My PAL VIC20 looks like this bt848_pal_comp_vic20.png apparently the cyan on later 6560 models should look mor...

There is some research data here (partly German) The PAL colour generation is a bit problematic because the even and odd lines have different angles/amplitudes for each of the colours. This is probably due to the way the colours are generated on the chip. In theory all dark colours (2-8) should have...

I would have thought those Meanwell thingies would work fine, but apparently not then. One thing you could do is get a separate 5VDC supply from somewhere and then combine that with the 9VAC from an old VIC-20/C64 PSU. There are Y-cables that let you combine these. Or at least there used to be, I ha...

Very good video. The VIC (6560/6561) in fact has sepearate luma resistors for each colour, see for example this thread (partly in German) https://www.forum64.de/index.php?thread/110862-helligkeiten-der-c64-pal-palette-zum-100-mal/&postID=1699320#post1699320 I think it also may have been discusse...

Sorry if I sound ignorant (which I probably am) but I understand this PSU has basically two sections with transformers in it. Would it be possible that the noise from the 9V section gets coupled into the 5V section or vice versa?

Great, thanks.
I stole a SN7406 off a spare C64 board, VIC-20 now loads from disk properly.

Don't recognize the logo - it's some stylized F
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