I was checking out the sources I have and found the following sites:
http://www.earlytelevision.org/images/621_manual.pdf
http://www.earlytelevision.org/holden_621.html
http://www.earlytelevision.org/image...-Rider-TV1.pdf
They look like they have all the things you would be looking for, to include one is a restoration already done. Hope it helps.