Ok.
Thanks a lot, fellows.
I have a RGB A1942 monitor. I live in Brazil: PAL (NTSC automatic) TVs, 220V/60Hz mains.
But missing 200 lines in the bottom of screen is just the not-that-bad issue and trash the sound. Some games simply blurs the screen of my monitor.
I don't want to pull out the Alice pin, but follow it 'till the resistor and put a switch (and a regular resistor) instead of it. Simple like that.
Don't need to change the modulator, I have other PAL and NTSC machines here. But the 1200 is my main machine.