1988? Bontempi System 5 AT 808 Electronic Keyboard

A fairly annoying keyboard from the late 1980's or early 1990's. It has some complex rhythm patterns and a few interesting sounds.

Good features:
30 rhythms (many of which are useful)
60 sounds (a few of which are good)
8-note polyphony in "5 Full Keyboard" mode (3 if accompaniment is on)
5 pads that can be set to "special" sounds (bass drum 1, orchestra hit, snare 1, "hey" sample, "huu!" sample) or drum sounds (bass drum 2, snare 2, hi bongo, low bongo, closed hi-hat)
Separate up/down volume buttons for master, accompaniment and rhythm
Accompaniment chords can be major, minor or minor 7 (e.g. D7) as defined by holding two notes in left section. (root + major 3rd = major; root + minor 3rd = minor; root + whole step down = minor 7 (e.g. D7 = C+D))
Tempo up/down buttons

Bad features:
Volume reset to loud when turned on or when built-in demo song is played
"System 5" sample then orchestra hit plays at power on
A short song plays when a sound is selected (this feature can be turned off)
A measure plays when a rhythm is selected (this feature can be turned off)
Drum noise plays when changing settings (vibrato on/off, chorus on/off, sustain on/off, etc.)
No display to indicate what number has been selected
"Ciao" sample played when turned off
Auto power off after about 4 minutes

I could not figure out the "Chord Program" section (6 buttons on left side)