Thanks you very much for this "hard to find" service manual.
Will help a lot in repairing this receiver.
Text excerpt from page 4 (click to view)
SS-WS550
REVISION HISTORY
Clicking the version allows you to jump to the revised page. Also, clicking the version at the upper right on the revised page allows you to jump to the next revised page. Ver. 1.0 Date 2001.08 New Description of Revision