 The Mono/Poly also did not include a digital memory like its sister the Polysix, because its focus was again on experimentation.Other drawbacks are the chipboard construction on the base and sides of the unit, which tend to get damaged easily or allow screws to come out, and the rubber contacts under the keyboard, which tend to wear over time resulting in dead keys; this may be fixed with a little cleaning and/or obtaining a new rubber strip, as Mono/Polys are fairly easy to disassemble.As far as circuit reliability, they tend to fare well by the standard of most analog synths.