Problems with PSX 1000 series and some games

[daz greenfield]

I'm having problems with dino crisis on my playstation 1000 series but not with later model psx. all the psx ive tried have stealth 3 chips in them which i chipped. is there a patch to cure this or do i need to get a later playstation to play these games? also on the later psx i can turn off the chip by holding down reset for 3 secs but it doesn't work on the 1000 series, is this part of the problem?