Hi to all,
Hi ARC Tech-109,
A quick search yielded the full Sony FD-40A service manual as a free pdf file.
Download it here, file is 6.4Mb :
https://ia904504.us.archive.org/28/i...FD40A_SONY.pdf
Hope this helps you repair your WatchMan, please keep us informed of progress,
Best Regards
jhalphen
Paris/France