[Milsurplus] Looking for Technical manual for PRC-515 or RU-20, maintenance chapter

[Dongen, Nico van]

I'm looking for the technical manual for the Collins PRC-515 or RU-20 as it was called in Yugoslavia.

I know the website http://www.radista.info has the Collins PRC-515 manual but this manual does not contain chapter III and IV, maintenance and parts list. I assume these two chapters are listed in a separate document.   

Because I'm troubleshooting my set these documentation is most welcome.
Anyone with experience in faultfinding on these sets? My set is only producing audio noise that can be controlled by the volume control but nothing else is working.

Thanks