This is a good quality scan of the service manual which includes an assembly diagram, block diagram, schematic, and parts list. Exactly what is needed to repair my KR-V55R receiver.
Text excerpt from page 2 (click to view)
Precaution to replace Optical block (KSS-213C)
Body or clothes electrostatic potential could ruin laser diode in the optical block. Be sure ground body and workbench, and use care the clothes do not touch the diode. 1) After the connection, remove solder shown in the right figure.