You do NOT need a mod-chip in order to play a copied game all you have to is:
Put a spring on the cd lid sensor. Do this to trick the psx to think the lid is closed.
Now power the playstation with no cd. When the playstation menu apears goto the option that lets you play music. Put in a cd game that works normally. Lift the spring and place it back down to make the playstation think the lid was opened and closed. Now press the play button. Now from the point you have 2 options. The first I'm going to tell you has less music quality during gameplay.The first thing you can do is:
When the cd stops spinning take out the normally working cd, and put in your backup/import. Then exit the music menu. Then your game should start. If the cd is specially protected then sometime during startup you will get an
Software Terminated This system may have been modified. Only game know to do this is Crash Bash and the Crash Bandicoot serious has the potential of giving you this message.
The Second method is:
When the cd stops spinning after pressing play with keeping the normally owrking cd in the drive exit the menu. When the black Playstation logo screen appears quickly swap the cd's. You have few seconds to do this and you eventually do it like nothing. This method is better quality of the two.
Note: If you don't have a spring you can take piece of tape and gently press down on the lid sensor with it.
Also the lid sensor is in the right top corner.
This is for those who don't want to ruin thier warranty on their playstation.