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I don't know about using felt, but FWIW the PTFE sheet / double-sided tape solution is still working perfectly for me several years on.
It depends really what is causing the stickiness: is it that the new pad has moved? In which case you need some different adhesive/tape. Or has it deformed - in which case using some thicker PTFE would probably help. Or is it that grease has dripped onto the pad - in which case just cleaning it might help but I'm not sure how to fix that long-term.
Attaching felt to all the keys sounds like a lot of work, but good luck if you try it!
Kawai CA95 / Steinberg UR22 / Sony MDR-7506 / Pianoteq Stage + Grotrian, Bluethner / Galaxy Vintage D / CFX Lite In the loft: Roland FP3 / Tannoy Reveal Active / K&M 18810
- Inconsistent let-off. The let-off on most keys is near imperceptible, the way it should be I presume. On a few keys however, especially some of the black keys, it is VERY noticeable, to the point where playing softly is not possible without having notes drop out. It actually takes a considerable amount of force, relatively speaking, to get past the let-off when playing softly.
I have this too. I wouldn't say it's a problem, but on my DP, some keys definitely have an extremely light letoff, and the ones with the most pronounced letoff tend to be the black keys. I suspect this is because the rubber letoff nub is in the same position for both white and black keys, though the pivot for the black keys is farther back (though the equivalent would be the same on an AP, right?).
The particular grand I get to play on the most has a much more pronounced letoff, so I tend judge everything against that...but it really just goes to show how widely varying our opinions can be as they're shaped by our own personal experiences on different pianos (which themselves vary a lot).
I also notice that some of the black keys have a more audible "thunk" when the key is released. It sounds EXACTLY like the "fallback noise" you can enable in VT so in a way, kudos to Kawai for the noise in their actions sounding so authentic! But as adjacent keys can be virtually silent when released, at some point I might open the thing up and see if there's a felt or cushion or something that's been compressed more than others.
Hi, sorry for my poor posting skills and many thanks to Iolatu and to all that have contributed to this thread. I bought a few years ago a new CA67 and had immediately problems with inconsistent letoff (as in the posts by travis524 and Gombessa I have 'cited' above). I contacted the seller and they sent a technician, but he kept the instruments for several months without solving the problem. Then, taking advantage from the instructions found here the open the piano, I improved a bit the situation by exchanging the central defective letoff elements with those in the extreme bass and high keyboard sections, just because they were working slightly better and the central region of the keyboard is the most used. I call letoff elements the parts, apparently made of silicone, resembling sort of combs, an octave-long, that support the 'teeth' that are hit by the hammers to provide the resistance that simulate the letoff. (I'm really sorry for this rough, imprecise description). Now, a couple of months ago some keys became very slow and sticky and I'm about to try to fix them with the PTFE layer method. I'm quite confident with this, but I'm wondering if someone has found some improvement with of the uneven letoff problem. I thought that a way could be to buy some new letoff elements to replace the defective ones. However, I wouldn't be sure that the new ones would work better and, in any case, I couldn't find any seller.
Hi everyone. New MP11 owner here. Mine is about 6 years old. Bought it used. I'm also an MP6 owner. Different horses. Both very good stage pianos.
While I'm getting used to the GF I realised that there are some small problems. From the 4th octave onwards nearly all of the black keys make a loud release "thunk", like a fallback noise. Before that point all the black keys are nice and quiet. All the white keys accross the board are very quiet. Maybe something with the casing, the balance rail or is it "normal" for the GF action?
Also the let off is very different to the one of the MP6 RH action - much more discreet - but it's also very incosistent around the keybed. I think this is not how it was designed.
Any ideas how can I sort out these slight problems (for the time being they don't affect my joy while playing this excellent DP)?
PS. Excellent thread for all GF action users who are quite capable with tools. Thanks to all the contributors for the fantastic ideas and suggested solutions.
Yes I know Kevin M I 've seen that thread while I was searching the forum for an answer. But it seems that there is no obvious DIY solution (or am I wrong). Apparently it's the casing...I guess. I'm not in anyway obsessive to complain about product quality etc. etc. I just love to play. If something is wrong and can be fixed good. If not it's ok with me as long as the instrument is good. And the MP 11 is really good. If there is no solution I will experiment in the near future with loosening the casing on that side.
Dear all Just to give a follow up to my post of July: I repaired my daugther CA67, by replacing all slip tapes (Teraoka 777 sold by Kawai France). Same procedure as stevenk123. Perhaps I made a mistake, but I added a very small amount of silicon oil on the new PTFE layer of each key (advice given by Kawai technician from USA). Remark from stevenk123 about oil and glue migration risk make sense... I hope he is wrong ! Thanks for all your information shared here, especially adrianR2, Terry Michael and stevenk123 My daughter is now playing this piano for 2 months, the action seems to be perfect. I hope it will last for a long time... As it took me hours to repair ! The Teraoka 777 given by Kawai is not exactly the same slip tape as the defective original in my CA 67 piano, but it have the same height, before the capstan start to form it. After the operation, the keys have the same height, no need to tune the keyboard. To show 2 issues seens on our CA 67 before operation, I shared 2 videos: KEY TAKE A LONG TIME TO COME BACK IN INITIAL POSITION KEY HARD TO PRESS
I 'm a very disappointed with Kawai. An issue can happen, but the way they decided to treat it (I shoud say "not to treat") is not correct. Especially for a well known problem on their production, happened just after guarantee period.
18 months after my intervention on my daugther's Kawai CA67, the piano is still OK. Oil didn't cause any issue (that was a very very small amount of silicon oil). That is good because I spent a lot of time to repair this piano! I never got any answer from Kawai support (France) about my oil question.
Symptoms: Key is initially harder to press down, and clicks
Alternatively, keys are slow and heavier to push down.
Fix summary: Clean pad / hammer capstan with WD40
Remove splinters / sand down rough edges
Repair instructions: Open up the piano, and clean the capstan and contact pad on the keys. A small amount of WD40 on a cloth or cotton bud did the trick for me (see second video above).
Another case of splinters appearing after I'd removed the keys to fix the balance rail, though the symptoms are somewhat different to the other case. Simply open up the piano, take out the key and remove rough edges.
Hi --- Any chance you can repost this video? MY P11 was stored on its end for 8 months during the worst of Covid by my landlord while I was stuck 3000 miles away. I"m trying to fix it now - many keys hardly press down at all. Thanks! - Jeff Newton
Selmer Mark VI Tenor (‘73) & Alto Sax (‘57), Yamaha YSS-62 Soprano Sax (‘87), Conn Naked Lady Baritone Sax (‘52), Conn New Wonder Tenor & Alto Sax (‘24), Yamaha WX5 Wind Synth (‘13), Kawai MP11 & ES-110, Numa Compact 2x, Casio PX5S, Roland VR-09, Hammond E-112 (‘69).
VPC1 keys are finally behaving and not sticking. stevenk1231 posted his method on page 17 of this thread and I gathered all the supplies to follow that. Since my VPC1 is still under warranty, and the local repair shop in Atlanta couldn't fix it, Kawai sent replacement slip tape and a little bottle of oil for lubrication. After replacing slip tape on a couple of keys with the McMaster-Carr teflon recommended by stevenk1231, I noticed the teflon tape has a good bit more key clicking noise, so I see why Kawai uses the softer slip tape. stevenk1231's post did help a lot though, with the method he uses to clean the capstans. The adhesive sticking to those seems to be the biggest problem and cleaning capstans with Goo Gone, followed by Simply Green helped tremendously. At some point I'll probably have to open it up and clean other capstans, but for now, I'm very happy to finally have VPC1 playing like it's brand new!
First, thanks to lolatu for starting this super-helpful thread.
I own a Kawai CS11 (GF2 action). Over the last few months, I started working on controlling dynamics (I'm a beginner), and I became aware that I could not maintain a steady dynamic on simple Hanon exercises, or precisely ramp from e.g. p to mf across an octave. My piano teacher confirmed that my technique was fine, and I eventually realized (by moving my piano bench to different positions along the keyboard and playing the same passage at higher or lower octaves) that the CS11 itself was at fault.
To make the situation precise, I measured the piano's velocity profile. I did so by placing a weight at the edge of each white key (holding the key in the up position), and then letting the key drop once the weight was in place. I used three weights (100g, 150g, 200g)  on each of the white keys , and measured the resulting key velocity using standard midi software  on a laptop (connected to the CS11 via USB). To ensure accurate data, each key was tested 3 times with each weight.
The midi data files were then analysed via a Python program (which I wrote) to process the midi data files and to generate figures.
Here is an example of the resulting figures. . As a rough guide, a velocity of 25 corresponds to p, so you can see that the larger of the velocities at 100g correspond roughly to pp, and those at 150g to p. The inconsistencies at 100g are severe (e.g. many keys do not respond at all), making it essentially impossible to maintain a uniform dynamic at pp. A steady dynamic at p is also very hard for me to maintain over much of the keyboard. Similarly, steady ramps from e.g. p to mf are interrupted by noticeable irregularities which are obvious to other listeners (e.g. piano teacher, technician).
Recent replacement of the slip-tape and contact board by a Kawai-directed technician has not resolved the issue. I am still in discussion with Kawai on possible next steps.
It would be helpful to have similar data for some of the newer Kawai digitals or similar options from other manufacturers. If anyone has a newer Kawai digital (e.g. CA99 [GF3] or Novus NV5S [acoustic action]) or one of the higher-end Yamaha digitals (e.g. NU1X), and would like to do a velocity profile, I can assist: if you provide the midi files, I can process them into velocity profiles.
 I used a "Truweigh" 100g weight, which has just the right dimensions to sit nicely on the white keys. I superglued a 50g or 100g weight on top of the 100g weight to create a 150g or 200g weight. I found that heavier weights (e.g. 300g) (created in the same manner) "bounce" when the key drops, leading to unreliable measurements.
 Only the white keys were profiled due to the practical difficulty of placing weights securely on the black keys.
 I used Pianoteq. A free trial version is available, and works just fine with the white keys (IIRC). It records standard midi files.
How many times are you going to cut and paste the same message?
If the digital piano action is working properly, your inability to control dynamics in a simple Hanon exercise is caused by your technique. Every acoustic piano feels different, and we learn to listen critically and make minute technical adjustments, on the fly.
If the digital piano action is working properly, [...]
Well, that is actually the unanswered question. Is the action working according to the design specs of the piano? Or is the original design flawed? At the moment, I'm not sure of the answers to either.
Agreed: the inability to control dynamics is a function of the piano action and technique. The data I collected isolates the effect of the piano action on the dynamics. The data shows that the touch weight of the keys sometimes exceeds 100g. But the more relevant issue in terms of dynamical control is that the touch weight fluctuations so much across the keyboard, from note to note.
Since you have other digitals (e.g. the Yamaha CLP-635) and review digitals, could you collect some data? It would take just a few minutes once you have the laptop & connection set up.
My broader concern is that manufacturers are creating new actions for these digitals that differ from well-tested acoustic actions, are making these available to the public. There are many bugs in these new actions, as e.g. this thread demonstrates. Some of these bugs might be fixable in the field (e.g. slip-tape replacements), but some may be inherent design flaws which cannot be so easily rectified. So, it is valuable to get clean, objective data (insofar that is possible) on how well they are performing so that customers can make informed judgements on purchases.
How many times are you going to cut and paste the same message?
Apologies for any offense. I was trying to reach different audiences, to whom the message was tailored.
The data shows that the touch weight of the keys sometimes exceeds 100g.
Correction: "touch weight" ---> "the minimum weight needed to register a non-zero key velocity" (Is there a technical term for this weight? The touch weight is the minimum weight needed for the key to move, not necessarily to register a non-zero key velocity).