Scope measurements:
These are from the second board, after removing the modulator. Channels:
1 = VIC II pin 8 (IRQ) (used for trigger, not shown here)
2 = VIC II pin 14 (color) (to GND via 1k)
3 = VIC II pin 15 (sync/luma) (to 5VCAN via 500 (2 1k in parallel))
4 = VIC II pin 21 (color clock)