I had to replace the audio out board in my PA2x ages and ages ago after a drunk dancer knocked the 1/4 inch jacks and broke the outs. (I use right angle connectors now
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)
My STRONG recommendation would be to replace the main audio board. They are tricky to remove, but not difficult if you take your time. And the part should still be available.
Theoretically you COULD hotwire from the Main Outs tracks to the 1/2 outs tracks, but you STILL need to remove the card to do so , as these are on the underneath side. You would need a good quality multi to isolate the tracks you need, as they are not obvious.
If it is just the actual socket that is broken, again with the board removed from the keyboard, you can replace JUST the sockets. Again, tricky, but not all that difficult if you are handy with a soldering tool, and de-solder techniques.
I had to do a full replacement as my board was cracked as well..
If you need further info, as Nick suggested, get on over to the KOrg forums.
Dennis