It has OS 2.3 Through tweaking I found that it does not freeze (as much) when I switch its master MIDI mode to POLY and MIDI enable to everything - e.g. in 2 days it froze once and when I used keys on the keyboard - and when it freezes - it still accepts sysex messages over MIDI and plays as it shou...

Got me an ESQ-1 from eBay. Connected power and a single audio output - but nothing else. It turns on, says battery power is low, but all buttons seem to respond well and all presets play well and sound good until one minute passes - then whatever sound gets stuck as well as all controls do not respo...