Repeated keys muffled in Kawai CN39

[Stephen M]

Hi,
I bought a Kawai CN39 2 years ago and it's got something like a digital sound flaw in the hammer action. When you quickly repeat a key, the sound of it (that specific key) is muffled. It's noticed especially in fast repetition or in repetition of chords - even more in organ sounds than with piano. It doesn't stop playing quite nicely but it's very annoying. Anyone know what to do?

[chrisw]

Does it make any difference if you ensure that the key you are playing comes back to the very top before playing it again ? Do you know if the CN39 has double or triple sensors ? Is this something that has just developed or has this behaviour been there since new ? If it is the same on all keys my guess is that it is not a fault. On an acoustic upright piano the key has to almost fully return to the top before playing it again in order for that note to fully sound a second time.

[Stephen M]

The muffled volume when a key is repeated immediately may indeed occur when the key hasn't bounced all the way back up (with piano or organ sounds). When it does happen (it doesn't always), it hardly matters how hard the key is played. I've never experienced that effect in any other of the pianos I've played in 48 years, though, and I'm not sure normal piano keys will always bounce all the way up in very fast trills. The problem tends to be especially when playing songs with notes repeating 2 or 3 times (not necessarily fast). No such problem existed with the several Yamaha and Kawai digital pianos I went to try out with one same song and piece at Richard Lawson's Amersham yesterday. I went there because the Kawai technician had suggested by email that I go to a shop, but I'd ordered it online on 19th March 2020 from Rimmers that's very far away. The flaw existed ever since I assembled it new, and the warranty recently expired. I hadn't complained or sought refund originally because Covid-19 lockdown was introduced the same month.
Apparently it has triple sensor action, and this is supposed to make trills smoother - maybe it's something wrong with that sensor. Lawsons say they'll be unlikely to buy it from me though (suggested private like Gumtree).