Have just copied my circa 1982 O & K RH6 manual. These are pretty sparse on the internet so thought it might be of use to someone here.
If printing it double sided make sure to specify that it is landscape and flip the page up. It should read properly then with info on the top page referring to stuff on the bottom page.
Content is - Operation, Working Equipment, Servicing/Maintenance, Hydraulic systems, Gears/ Slew Ring, Brakes, Travelling Gear, Scheduled servicing, Repairs - undercarriage - hydraulic cylinders, troubleshooting, Parts list including wiring diagram. Cheers
File uploaded to the download-area /Holger