Gustavo,
Fran is right...the issue with the defect on the MZ-2000 looks to be very minor....if in doubt,ask if an independent technician can examine it.
Leaving a newer keyboard on for an extended period of time is much less damaging than turning it on and off many times.
The MZ-2000 is probably your best bet.


Fran,
This was an earlier post by you....
" I thought it would be interesting to post our feelings of the Arranger keyboards we each owned...
Casio MZ2000,,First impression was okay, but did not like overall.. "

Your take on the Technics/Casio connection is only a guess,and based on assumptions.There are way more similarities than differences.
The MZ-2000 was a very different product for Casio,and very much like a Technics KN series,which quite possibly,were the reasons that led very many people to believe there was a one time connection.Remember,the MZ was one time model for Casio.The WK series,although very nice, are not in the same league as the MZ-2000.

Ian