#'Budgie' chip
The clocks are generated by the 'Budgie' chip, from a main oscillator.
That osc is 28.63696 mHz for NTSC and 28.37516 for PAL. The NTSC color
burst is generated from it, so I'd say that you'd have to have the right
crystal to generate NTSC *composite* video. The power supply only supplies
DC, so there's no way the system could decide pal vs/ ntsc that way. It
must be internal… Now that I look at the prints again, I do see the
jumper. it's R203, which grounds a signal called \ntsc. Looks like you'd
have to move R245 to R246 as well. Then you'd have to change the RF
modulator- it's a sealed can. If you only wanted composite video, you
could get away with the 3 jumpers & changing the main osc.
At least, that's what I think after looking over the schematics. It's been
a while since I opened up a 1200.
-Jim
MOS via Autopilot & Amiga