Harold Rhodes is truly one of the great innovators in electro-mechanical keyboard design. (btw, here is a fantastic tech page for all of these Fender Rhodes instruments.) He began constructing his first prototypes out of B-17 bomber hydraulic parts and so on and eventually became the father of one of the four most used keyboard sounds in popular music. (The Hammond organs with percussion, the Wurlitzer EP and the Honher Clavinet.) I recently worked on a "pre-piano" which many people built from instructions after WW2 and Harold received a medal for his work developing the idea. Erie sounding thing.
The products seen below relate very little to Harold. Fender continued using his name here for two keyboard products which ARP engineers designed from what I can tell. The Roland Rhodes MK units were actually voiced by Harold Rhodes I'm told.
The synth instruments below though represent the culmination of the efforts of one of the greatest synth companies, ARP. Chroma is the first computer controllable synthesizer. A DB-25 type port on back referred to as a 'chroma port' could interface to an Apple II and I imagine commodore probably did something with it as well. The Polaris brought back sliders though some are 'lo res'. (resonance in particular). It kept the chroma port but added MIDI also. Both very cool instruments.
Later on Roland would take a crack at more Rhodes labelled products also, the MK80 and MK60 and model 760 keyboards. The MK's were nice weighted feel machines and Harold I was told by Lee Sebel actually did take part in voicing those units. Some day I'll try to put up some more info on them. Meanwhile here's a link for other Rhodes Information
Rhodes Chroma Fender Chroma Polaris