The Sony AV-3600 service manual was what I needed for the repair of this unit
Thanks for the good service
Text excerpt from page 7 (click to view)
<Removal of the MD mechanism>
Removing the spindle motor (See Fig.9)
1. Unsolder the part e of the flexible wire extending from the underside of the chassis assembly to the spindle motor. At this time, do not spill flux on the gear and others. 2. Remove the three screws G attaching the spindle motor and detach it from the chassis assembly.
Slit washer Worm gear
Shaft holder e
Spindle motor f g Pickup unit
Removing the pickup unit (See Fig.9)
1. Remove the slit washer and the worm gear from the underside of the chassis assembly. 2. Remove the screw H then detach the shaft. attaching the shaft holder,
3. Pull out the part f and g in the directions of the arrows to remove the pickup unit and the lead screw.
Removing the pickup (See Fig.10 and 11)
1. Remove the screw I attaching the lead spring, then detach the lead spring. 2. Pull out the shaft from the pickup. ATTENTION: When handling the pickup unit, touch the parts marked in Fig.11 only. Fig.10