To install the 7800 mod board you will need to remove a 14 pin IC and replace it with a socket. The board includes the socket that you will need to solder in place of the IC. You then insert the board into the socket. There are 5 additional connection that need to be wired to various locations as well.
Step 1. Carefully remove the IC indicated. You will need to
de-solder all 14 pins and remove the solder from the holes.
Step 2. Replace the IC that you just removed with the included 14 Pin socket.
Step 3. Remove 3 resistors indicated below:
Step 4. There are 5 other connections that need to be wired to the mod board to various spots on the 7800. The 5 locations are show below in the two pictures. One is located on the opposite side of the board.
Step 5. Connect your output cables and or jacks to the output connections on the 7800 Mod board.
Step 6. Insert the mod board into the socket. Photo below shows a completed install.