I had a solo plan (at first Keough and later on 401k) that ws started in 1981. Only filing was a 5500-R in 1985. Having a hard time finding out what the requirements were at that time. IRS has old forms but not old instructions. Even Google Books only goes back to 1987, although the description says it goes back to 1985, it lies.
Plan was terminated in 1997, so I am planning on filing a 5500-EZ final for that year under the current no-penalty late-filer program for solos, which will be open until June 2015.
Was the 5500-R all I needed at that time? Assets in plan were always small, well under $100,000 in 1990, but I don't know what the cutoff was prior to 1990.
Would be happy to read the instructions myself, but where to find them?