If the main chips are socketed and sprung clip type, probably
grime/corrossion , note orientations, clean/joggle the pins and reinsert ,
perhaps with a turned pin socket between IC and the original, if not
prepared to remove the original sockets.

aye, did that already, some of the pins have turned witeish, couldn't remove that white stain

that turned pin socket is a very good idea, i think i'm going to head that way before spending 30$ on chips

thanks a bunch