Recent acquisition from the same source as the Astron. Had some burnt components on the control board. Finding information or schematics on this thing is impossible. Kenwood says this unit doesn’t exist and they have no record of it (don’t mind the thousands of brochures it was advertised on) and Astron, who manufactured it for Kenwood, never answered my inquiries. I ended up finding specs from an old advertisement for a Kenwood rig and I matched it to an Astron RS-20. I ordered a control board for that model of Astron and resurrected the Kenwood KPS-21. Works great!