You can't change the composite or RF modulation outputs by switching PAl/NTSC modes on the custom chipset. The AA chipset allows the RGB modes to switch between PAL or NTSC, but not the composite or RF out.
You can change the A1200 over, but it requires modifications to the logic board and an NTSC RF modulator. US120 power supplies are also hard to come by these days, though at least you did find a solution to that problem.
Hope this helps.
//RC//
P.S. Directed at anyone that complains about the price of USA/NTSC A1200s, anywhere:
This is exactly why NTSC A1200s cost so much more then PAL A1200s. You can buy a PAL system, then have everythign changed over, pay a couple hundred in parts and labour, plus a power supply adapter or a new north american power supply, or you can spend the same total for a NTSC system in the first place.
