This is the tranciever that established Yaesu in the world ham market. It was able
to sucessfully compete against Swan, Drake, Clegg and Gonset, and started a trend that led to the eventual demise of those US ham radio manufacturers.
This rig is all solid-state except for a 12BY7 driver and a pair of 6JS6 finals. Features plug-in cards containing circuits for ease of service. The 'E' model featured an RF speach processor for the transmitter, the 'EE' did not have it. Rear sockets
are for connection of frequency counter, transverters, VFOs, all of which were sold by Yaesu.
There were a number of improvments made during the E/EE production run. The most obvious is the relocation of the processor level on the outside of the clarifier from inside the top cover. (pictured is a late-model E - look in the lower right corner of the front) The processor control required some adjustment to sound right
depending on the band that you were operating on. Improvments were also made in the noise blanker and power regulator boards during E/EE production.