Don O'Rourke of International Calculator and Computer has been in business for many years in the same location in Orlando, Florida. I patronized Don's shop in person for a number of years when I was in college nearby.
He's a great calculator historian, well versed in all that is HP, and has a national client base; all this from a small and very unassuming store front, complete with 'bargain table' for those hard to find, and sometimes hard to identify, items.
Don is an absolutely safe bet for HP repairs and service.