Zenithfan over on the Antique Radio Forum is working on an RCA Strato-World 3-BX-671 portable shortwave receiver, and he was having trouble finding PDFs of the manuals. I had collected the RCA service manual, the Riders service info, and the Sams service info from various sites on the internet, so I'm putting them up in my manual archive for him.
The RCA service data is from Brian McCallister's Vintage Radio and Audio Pages. I converted Brian's GIFs to a PDF.
The Riders service info is from Nostalgia Air.
I think the Sams info is from BAMA.
RCA Strato-World 3-BX-671 service data: