do the swap trick
get an original PSX game (preferably something with a lot of audio tracks)
and you'll need something to hold down the lid sensor.
Insert your original CD.
o Remove the original CD when the motor changes to 2x and replace it
with your backup CD.
[If you did this right, you *SHOULD* see the black PS screen now.]
o Watch and listen to the CD motor. It will slow down and then
speed back up to 2x.
o After a few seconds, the CD motor will slow down again. Replace
with your original CD once again.
o After another half second or so, the original CD will speed up again.
Finally replace your backup CD.
from the gamefaqs swap faq http://www.gamefaqs.com/console/psx/game/916392.html
Alternatively all of the modchips made for the PSX were just pic chips, if you can find the hex you can flash your own for about $2 worth of parts (chip + wire) if you don't have a programmer I'm sure you could find someone to program it for you. There are only 6 or 8 VERY EASY wires to solder (depending on your model) and backups/imports/homebrew will play on that console just as well as originals do.
don't buy those stupid plug mods, they're expensive and they basically just make the swap trick easier to do.