Sites like Manuals-Pump or Tradebit often list the "Korg Pa700 Service Manual" for $15-$25. Proceed with caution. Many are just the User Manual renamed, or low-res scans missing page 34 (the power amp schematic). Check the preview; look for the actual circuit diagram.
Send your Pa700 to an authorized Korg service center. The cost is usually a $100 bench fee plus $80/hour. They have the manual. This is ideal for power supply issues (risk of fire) or main board swaps. Korg Pa700 Service Manual