Hi Bill
I also have a Mk IV (C3 DKV). I experience the pedal problem often, 3 times in the space of an hour when playing files on the HDD through DKVBrowser. I can fix it simply by going to standby mode and on again. I rarely have the problem when playing midi files from my laptop using VanBasco's Karaoke Player.
I power down and turn the power off at the wall socket every night.
This seems to be an identifiable and common bug affecting a lot of users - probably every Mk IV user. Do you know why Yamaha doesn't put out a fix for it?
Many thanks for your knowledge, wisdom and help in these pages.
Geoff
Long live Disklavier