very good manual, with detail and clarity in esquematic diagrams and waveforms .
Text excerpt from page 14 (click to view)
CDX-5V661/5V661A/5V661D/5V661S
2-17. OP BLOCK ASSY
1 two flexible board (CN201, 301)
3 cover (flexible)
2 two screws (special flat head M1.7)
5 Rotate the OP block assy in the direction of arrow B. Remove the OP block assy up straight carefully to prevent the portion a from being caught by the tray. a
tray
4 Slide the lever fully in the direction of arrow A. A A
A B A
4 Slide the lever fully in the direction of arrow A.