The Sony AV-3600 service manual was what I needed for the repair of this unit
Thanks for the good service
Dave
Text excerpt from page 35 (click to view)
3.5.5 Removing the woofer (See Fig.5) � Prior to performing the following procedure, remove the side cover and the front panel. (1) Remove the four screws E attaching the woofer. (2) Disconnect the red and black wires from the two terminals on the woofer. 3.5.6 Removing the woofer (See Fig.5) � Prior to performing the following procedure, remove the side cover and the front panel. (1) Remove the four screws F attaching the woofer. (2) Disconnect the three black wires and the black, red and blue wires from the two terminals on the woofer respectively.