You will find a lot of info, including a schematic and service manual in the library on this site.
Just click on "library" on top of this page and look for "Marantz", then 6300.
The manuals are available for free download.
Hope this helps.
Dual 1019/Shure M97xE/Jico SAS stylus.
Thorens TD 146 & TD 166/Ortofon OMB5 and OM40 carts.
Marantz Mod 6170/Marantz E 5000 cart.
RCA 45 J-2 RP 190 record changer (1950).