Looking at your signature seems like destroys the amiga too, heh
Seriously, this fix allow this resolitions without flickerings and glitches?
As I said in the thread over on EAB, it takes about 15 mins to try it....what have you got to lose? Just lay the guts of your 1200 upside down on a desk, then when it starts to flicker short out the resistor with a flat bladed screw driver and see if it works.