Here is my list:
-Roland (D50, D70, JD800, JD 990, XV 3080, E20, ProE, RA90, G800, VA7): only a software problem with the VA7 which froze due to a wrong key-press sequence; just had to reload the OS and it worked fine.
-Korg (M1, T3): no problems
-Kurzweil (K 1200): no problems
-Akai (S1000, S2800): no problems
-Ensoniq (ASR10m): often freezes and I have to restart it, then it works fine (for a while, that is...)
-Yamaha (DX7, DX7IIFD, SY77, TG77, SY99,PFP100, 9000 pro): no problems
-Ketron (MS50, SD1, XD3): had to take the SD1 two times to the repair center for major hardware problems (three internal boards already replaced); right now I have a problem with a fuse which keeps blowing every time I power up the keyboard, so I think there is something wrong within the power section; next week I will take it to the repair center for the third time in six months.
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Korg Kronos 61 and PA3X-Pro76, Roland G-70, BK7-m and Integra 7, Casio PX-5S, Fender Stratocaster with Fralin pickups, Fender Stratocaster with Kinman pickups, vintage Gibson SG standard.