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Well, I'm too squirmish to try that!

I'll see what Kawai headquarters sways is the best solution - which my be just to leave it alone...

I've made a new video with a new approach to regulating slow keys. Enjoy.



Basically instead of liquid lubrication, you can buy thin sheets of PTFE ("Teflon"), and stick patches over the top of the existing PTFE using double-sided tape. It works really well in terms of reducing the friction, and achieving uniform weights to achieve certain MIDI velocities. The tape bond is secure, but does no permanent "damage" to the keys since you could easily peel it off, and is not messy like glue. I used 0.25 mm thickness mainly, but 0.5 mm also worked, giving more rigidity if you think the depression in the pad is too great.

I'm not sure if this works because of the coefficient of friction of the PTFE samples, or because the spongy layer beneath the PTFE has formed a depression that changes the geometry of the pad-capstan contact. Either way, adding the new layer fixes the problem.

Pending what brand/type double sided tape is used, over time, some will lose their stickiness and "slide" sideways. Just a hard earned lesson from a while ago.

Iolatu, excellent video to your excellent research!

Is the depression in the pad something that forms over time or is that present from the start, do you know?

Thanks! My first proper video using Sony Movie Maker.

The existing PTFE sits on what looks like a felt pad, and I think the depressions are there from the start, but I don't really know because I first looked inside when the piano was a year old. So they must form pretty quickly. I'm not sure if the felt is there just to provide some "spring" in the action, or whether it's intended to form a depression - maybe to stop the hammer slipping sideways or something. I *suspect* that the depression in unintended and could probably benefit from slightly thicker PTFE in the factory. What I do know is that in the Ravensworks version of the VPC1, they took out the PTFE and replaced it with felt. But I don't want to make any irreversible changes like that to mine.

@McBuster - that's a possibility. PTFE is used for its slippery nature, so it's hard to get things to stick. I will keep and eye out and maybe check up on it in a few months. I'll report back if there's a problem.

Good job on the new video lolatu.

Cheers,
James
x

Very useful videos lolatu.
Curiosity. Where did you pick up the part names please?
Is there a standard vocabulary?

I agree re maintenance manual. I wonder Kawai don't sell the full one.

I can't guarantee that all the part names are correct. I got some from the CA93 service manual, which can be found online if you look hard enough. I wouldn't say the service manual is very useful to someone just wanting to perform maintenance.

hi, thought I'd add this....

my CA97 started making a clicking noise when releasing (ONLY when releasing) the F key above middle C, if you pressed the E next to it at the same time then it wouldn't make the clicking noise when released

I opened up the back to have a look and it turns out the E and F keys are both at the edge of the 2 parts of the sensor board (the PCB board that the keys/hammers? strike) where they meet in the middle. So when pressing the F it lifts 1 sensor board up a tiny amount (so little you couldn't see it, but could feel it) and rubs/clicks against the other sensor board when it's released, this is why there was no noise when pressing both keys together as both boards were lifted a small amount so didn't bind

my fairly crude solution for now was to jam a wedge between where the 2 sensor boards meet and the metal rail that runs along the back so no movement is possible - I'm pretty glad this worked as I didn't really want to take the thing to bits..

I'm not sure if there's supposed to be any movement on the boards or if something needs adjusted so that movement should be allowed and a small gap between the 2 boards so they don't catch or if something is broken/loose that's allowing ANY movement

Hi paradice, thanks for that! Your description makes perfect sense, and jamming in a shim sounds like a good solution, so long as it works! Pretty sure the sensor boards aren't designed to move at all.

I wonder if it would also be possible to file down the side of the circuit boards by a fraction of a millimetre in the place where they touch? Maybe tricky without unscrewing the boards first, but more permanent.

Hi Lolatu,

first thank you very much for your excellent videos :-). My CA97 is now half year "old" and is now starting to make the noises you describe in your videos of the CA95. Together with a technician of KAWAI Support we could solve some of the poblems you describe here.

The only thing we can't get rid of in the moment is a rather loud noise of both the D4 and D5. Looking and listening closely with open piano we found a "smaking" sound produced inside the hammers bearing. If pressing the keys on one side several times eliminates the Sound for a short time.

We checked the "supporting" polyamide blocks,the key itself, the area of the contacts,...

In the moment we are "stuck"

Alexander

Hello,

I tried to "film" the noise (difficult to "FILM" a Sound :-) ).

Keynoise

Hmmm after slightly tipping or pressing on the "hammer bearing" during movement the smaking sound is gone. Seems to me that (maybe due to the increased hammer weights of the new GF II action??) the hammer bearings are "worn out" or a bit widened after only half a year and the grease inside the bearing produces the smaking sound.

Will try to measure them with a micrometer unit this week, but I could very cleary circle that in :-).

If this is the true sorce of that annoying noise it is time for a huge replacement order @KAWAI for new hammers.

@lolatu: Did you ever had an issue with the hammer bearings? Thanks.

Alex

Alex, may I ask if you have already contacted Kawai Europe to discuss this matter?

Kind regards,
James
x

Galuwen - thanks for your report. Your film is good!

It can be hard to locate the source of the sounds... did you try tapping on the front rail felt as in the video below, to see if that's where the problem is?

[video:youtube]https://www.youtube.com/watch?feature=player_embedded&v=CPTkDLAv228[/video]

If the squeak is coming from the hammer pivot, I don't know what to suggest (except maybe some more grease), since I didn't have that problem.

Hello,

thanks for all the quick replies. Yes I have contacted KAWAI Service and they opened "a case" on that.

And yes I tried to tap the front rail (the Service technician) it is OK :-).

Galuwen

Hi Lolatu,
Thanks a lot for information share.

I am a new guy for Kawai DP.
Just get a new CA67 but a bit dissapoint when recevived.
It is expected DP should be no Hardware issue than AP.

Unfortunately, i got some problem and hope to get some suggestion from you.

The shop said they can repair it by ship the DP back to shop for repair.
But due to the shop is not Kawai oficial dealer, they need to guess how to repair.
So, I want to do by myself rather than ship it here and there.

1. Noise key, will follow lolatu recommendation to check.

2. One key with around 1 to 2mm higher than other, would you mind to share any experience for how to repair it.



Thanks !
Cat

With the top of the piano taken off so that you can lift out individual keys, when you lift up a key, check whether there are paper spacers on the balance rail pins (careful not to lose them, since they may stick to the bottom of the key when you lift it). They are just thin paper rings that lift the key up slightly. If there are, then you can remove them. If not, you'll have to try to work out what is different about that key so that you can correct it. Or place spacers on the surrounding keys if necessary. You can swap the spacers around from other keys that don't need them, or simply make your own.

Glad to know this has been useful!

Wi the lid off you can assess the reason for the key being out of position.
Now then; if it originates at the pivot, you can shim the other 87 keys if necessary. A cereal box material such as cornflakes, will produce a lift. Cereal packets can vary.
The best quality card is found on Bakers Complete Dog Food (chicken flavoured) which has been instrumental in the construction of many model railway bridges and load bearing structures. . .not to mention 18 inch loudspeakers. Its easy to put a hole in one o them. .

Did you found out how to OPEN your piano CA67?

Is it the same procedure as on the CA95? > Just removing the top back panel and then shift the top cover a bit forward and lift it of?

Please be a bit careful not to break something :-).

Galuwen