Without going into the PAL/NTSC question (which was explained in detail in the earlier version of the Messiah 2 Install Guide but now removed for simplicity) I would say remove the colour fix cleanly by desoldering it. if you are not confident of your soldering skills, cut the wire in the middle and insulate the ends for another day in case you need to restore it.
Our other PS2 doesn't have the colour fix and it plays NTSC games perfectly on the multi-system TV.
hannanshah, are you sure that you have done the pal fix and not the ntsc fix. There is a difference.
The Ntsc fix(3.3v) is for US PS2 owners as it forces a PS2 to output pseudo-NTSC for Pal games which means 625 lines at a 50hz scan rate and a 3.58mhz colour carrier(NTSC colour coding which US TV's can understand.)
The Pal fix(ground) is for UK PS2 owners as it forces a PS2 to output pseudo-PAL for Ntsc games which means 525 lines at a 60hz scan rate and a 4.43mhz colour carrier(PAL colour coding which UK TV's can understand.)
I have a version 4 PS2 and have absolutely no problems with the PAL colour fix. Make sure you have the correct pins shorted for your Pal machine like in the pic below.
Version 4 PAL 60hz colour fix
You say your TV supports NTSC. If your TV supports NTSC then you don't need RGB. RGB doesn't use a colour carrier it just uses the scan rate to display the picture corectly. A UK TV which truly supports NTSC would support a colour carrier of 3.58mhz and therefore it wouldn't matter if you used a composite or s-video lead, as you would still get colour because of the supported colour carrier. Most UK TV's support 60hz at 4.43mhz(PAL60) but not NTSC(3.58mhz at 60hz).
The colour fix shouldn't affect PS1 imports apart from the fact they would boot in PAL60 just as PS2 games would if the fix was done. The fix should not boot any PS1 NTSC games in 50hz. The only thing I remember doing this was a NEO4 which made all NTSC PSX games run in PAL50hz with a nasty thick black border at the top or bottom of the screen. But Messiah has always displayed PSX games correctly in their native mode.
Also some patched PS2 cd games have an intro screen allowing NTSC/PAL switching even if the game is for instance an NTSC game. By selecting PAL resolution it can cause some odd side effects, like overly large black borders. Always try and select the correct mode for these games. :)
I can see why this subject was toned down on the Messiah2 install docs. :crazy: