Legendary digital synthesizer, released in 1991.

JD800s are known to suffer from the dreaded 'red glue' issue - the glue used to hold the key weights in place goes runny over time, damaging both the keyboard and the electronics. 

This one's had the keyboard stripped out and all residue of the red glue removed.

Modded as a custom expander module with wooden shelf. The modification is discrete, with the shelf slotting into the rails where the keyboard assembly would normally go. No holes drilled!

Powerful synthesis with over 60 front panel controls.
24 voice.
Sample-based oscillators and a fully digital signal path.
108 built-in waveforms.
64 internal patches, each consisting  of four 'tones' which can be blended together.
Built-in effects include Reverb, Phaser, Distortion and Chorus.
Multi mode allows 5 sounds on independent midi channels plus a 'special' patch which allocates different waveforms individual keys for use with drum kits.

As a bonus, this unit also comes with the SL-JD80-02 Drums & Percussion Dance PCM and RAM cards. 
These offer an extra bank of 64 synth sounds on the RAM card and 56 new waveforms on the PCM card, featuring drum samples from the TR-808, TR-909 and CR78 drum machines.
Second bonus: an additional M256E RAM card, offering another bank of 64 synth sounds.