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Posted By: elendil Kawai CA-97 disassembly / stuck key fix? - 01/24/19 05:14 PM
Hi,

I have two stuck keys (E4, G4) on my CA-97. The keys are stuck, but the stuckiness can be temporarily broken, after which they just have higher resistance than normal. The effect lasts for a couple of seconds, then they're stuck again. It started out as them being slightly stuck and has progressed into them being unplayable over the course of some months (without use). I don't know if something was spilled, but I doubt it. I'm very meticulous about that and my children ought to be too (but you never know).

I've tried "breaking them in" by playing them lots and lots, but it doesn't fix anything.

So, firstly: Anyone got any idea what might be wrong?
Secondly: Anyone know how to disassemble it without breaking anything so as to have a look?

I've tried searching for repair manuals, but either Kawai keep them close to their chest or my google skills suck. Or both.

Thanks.

I haven't had time to play for... well, years, so I've just left it for a good while and the warranty is long gone, I think. Now one of my daughters are starting lessons, so it sort of has to work.
Posted By: JoBert Re: Kawai CA-97 disassembly / stuck key fix? - 01/24/19 05:19 PM
Check this thread, it has a lot of information:

http://forum.pianoworld.com/ubbthreads.php/topics/2272103/Kawai_Grand_Feel_key_clinic.html

It's about the CA95 and the GF action, but most of it is applicable to the CA97 and GFII too.

The piano is relatively easy to open, via screws on the back. You have to disconnect a few speaker cables, but that too is not difficult.
That's an old thread, but it contains lots of good information.

If the piano is in warranty I'd seek warranty service.
If not I'd want to have the service manual before continuing.

Really really. Get one. It costs, but it's worth having.
I can't speak to the content of Kawai service manuals, but I'm betting they're similar to those from Yamaha.
Meaning ... very complete in all respects, including diagrams for disassembly.
Have you called Kawai to ask how much it would be for a tech to come inspect and fix the issue? It might be cheaper than you think (and for a CA-97, it would definitely be worth fixing, whatever the problem is).

And the action is pretty easy to understand, if you do care to open it up and look for yourself. The problem is there are parts (foam and felt pads, PTFE strips) that you may not have immediate access to in order to repair the issue.
Posted By: JoBert Re: Kawai CA-97 disassembly / stuck key fix? - 01/24/19 05:40 PM
Originally Posted by MacMacMac
That's an old thread, but it contains lots of good information.

If the piano is in warranty I'd seek warranty service.
If not I'd want to have the service manual before continuing.

Really really. Get one. It costs, but it's worth having.
I can't speak to the content of Kawai service manuals, but I'm betting they're similar to those from Yamaha.
Meaning ... very complete in all respects, including diagrams for disassembly.

I've opened my CA97 (just out of curiosity, not because I had a problem) when I still had it without a service manual. It's really not complicated if you are a bit handy with a screwdriver. First you remove the panel on the back, then you see which wires go to the speakers in the top panel, so you unplug those. Then you can remove that panel, and so on. At some point you may have to cut or untwist some cable ties, but that's about the worst you need to do to remove enough panels to get access to the action. All quite doable as long as you proceed carefully and with forethought.

Of course once the action is accessible, then the question is, if it is possible for the layman to see or fix the problem. My guess is a problem with the Ptfe tab of the affected key.
I've disassembled the MP11 with and without the service manual. It's absolutely doable without, but the manual IS super handy as a resource. It warns you of possible "gotchas" too, such as sliding a piece of paper between two parts so they don't scratch as you move them past each other.

Not having the service manual wouldn't stop me from my own DIY, but it's worth giving Kawai a call and seeing what it would take to get one.
Originally Posted by elendil
So, firstly: Anyone got any idea what might be wrong?
Secondly: Anyone know how to disassemble it without breaking anything so as to have a look?

This thread is about a different Kawai keyboard with a different keyboard action than in the CA97, but might be worth a peek.
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/24/19 09:48 PM
Wow, that’s a lot of quick, helpful replies! Thank you.

I’ll check out the threads linked to.

I reckon I would be able to pull it apart, but as one mentioned it’s just nice to know you’re doing it right and not accidentally breaking impossible-to-buy plastic thingies when you pry something apart the wrong way.

I should maybe have mentioned that I live in Denmark, so a service technician is out of the question, partly because Kawai isn’t a big brand here, but mostly because labour is crazy expensive.

I doubt it’s still under warranty, but I’ll give the (only) dealer a call. Who knows, maybe they’ll sell me a cheap service manual!

I’ll get back to you once i get it open and can’t understand what’s wrong with it.

Thanks again.
Hello elendil, welcome back to the forum.

Yes, I would strongly recommend giving your Kawai dealer a call, and possibly also Kawai's distributor for Sweden and Denmark, Juhl Sorensen. It's difficult to speculate what might have caused this issue, but perhaps the slip tape at the back of those two keys has come loose? If so, it should be a relatively straight-forward fix for a technician.

Best of luck!

Kind regards,
James
x
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/25/19 06:55 PM
Thank you, James. In my case they're the same and the customer support is good. I'll give them a call.

I think I'll try opening it up anyway to see if I can detect something immediately wrong. I'm scared of messing around with the keybed, but hopefully it's something simple as you mention. Since the behaviour of the keys are so distint, I'm guessing the problem should be apparant when you can actually see the action.

Unless it's under warranty a technician is probably my second choice due to cost and availability.
I'll be very interested to hear how you resolve this, I am having the same problem with my MP11, with almost all of my keys. No drinks have ever been allowed near it either.
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/27/19 02:26 PM
I've come somewhat closer now. I took off the top case, which was straight-forward and with little risk of breaking anything, in the hope that I could then see and remedy the problem.

I can see it, but I'm not sure what the remedy is.

First: A working key:


Next: Sticky key:


Take a look at the pivot point of the hammer action. For the working key the movement is smooth. For the sticky key, the pivot point "jumps" out of shape.

Any guesses to the issue? I can't see how I'd be able to fix anything without removing the action, which is... scary.
Posted By: JoBert Re: Kawai CA-97 disassembly / stuck key fix? - 01/27/19 03:36 PM
My guess:
You can see in your video the wooden part of the key at the bottom and the metal, screw-like part at the top (it's called a capstan). Between them you can see a thin black rubber cushion. What you cannot see is, that on top of that cushion, i.e. between the cushion and the metal capstan, there is a thin ptfe (teflon) film, to reduce the friction between the cushion and the capstan. The ptfe bit is like an adhesive film, like a bit of scotch tape (only ptfe). In other words, it is glued to the rubber cushion below with some adhesive.
My guess is, that this adhesive has failed in some way (maybe it got warm, or just old), and the pfte film has slipped, so the capstan is now no longer moving against the ptfe bit (with low friction), but is instead moving directly against the rubber cushion, at least partially, with high friction - or even worse, is even slightly sticking to the cushion, if there is a residue of the adhesive left.
If that is the case, then it can be fixed by putting a new ptfe bit into place on the cushion.
A technician can certainly do that. Or you can do it yourself, but then you need to source a replacement for the ptfe from somewhere. If you plan to do that, see the "GF clinic" thread I linked above. It also discusses this ptfe bit, iirc.
BTW, you don't need to take out the whole action to fix this. Each key can be removed separately. But you first have to remove the fallboard piece (the horizontal wood piece that bears the Kawai logo) - iirc, that requires to disconnect the cables of the tweeters (which is not too difficult) and another wooden strip beneath it that is screwed horizontally over all keys and prevents them from falling out.
All of this is doable (I know, because I did it with no ill effects), but should be done with care and forethought.
Posted By: lolatu Re: Kawai CA-97 disassembly / stuck key fix? - 01/27/19 03:52 PM
I see what you mean with the hammer pivot coming downwards on the sticky key. Not something I ever noticed. It still could be a problem with the PTFE tab that either needs cleaning or replacing: if there's friction there, the capstan would not slide back so quickly so the falling hammer would not change angle, causing the pivot to drop (it's a kind of half-circle resting below an axel, rather than a fixed hinge).

You won't need to remove the entire action - if it's like the CA95, once you've removed the back panel, the top slides off and you just need to remove the key cover and tweeter bar to remove individual keys.
The pivot in the video is the white/cream colored plastic piece directly above the metal capstan. I don't think we can conclude from this that it is a PTFE pad issue, personally. But it really looks like a revolving joint is coming loose from its hinge.
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/27/19 06:35 PM
Thank you for all of your points, gentlemen. I'll try giving the dealer a call and then removing the single key tomorrow if time permits and see if I can spot the issue. Glue or something similar coming undone could be a valid point, since we had a very long, very hot summer here, and I began noticing it in the fall.

You probably can't hear it in the video, but there's a really sticky sound like when your kid drops a lollypop on the floor and you discover it an hour later. In fact that's both the sound and the feeling.

I'll keep you posted.
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 11:02 AM
I called the dealer. They were very helpful, but: out of warranty as I suspected.

I took apart the key cover and the little bar on top of the keys for a better look. There is indeed friction between the capstan (thank you for the name) and the key for the offending key. In fact also for some other keys, but not as much.

I assume that there should be negligible friction between them, right? So that moving the capstan away from the key shouldn't result in any kind of stiction or "lollypop-off-of-carpet" sound. Is that correct?

Can I just pull out the offending key or are there considerations to take into account? In other words: If I remove the key, and maybe the rest of the action, can I put it back together again with little effort and especially little skill?

Now to source some teflon tape thingie.... hrm.
What action does Kawai recommend for such friction?
For my Clav the answer is ... apply lube to the capstan (and to some of the parts thereby driven).
Is that not the Kawai way?
No lube on a grand feel action (grease is only used for the escapement tab). There should be a small foam pad with PTFE/Teflon tape on the key under the capstan (on an acoustic piano it would be a felt pad).

The PTFE tape has been reported to slide off in some cases (temp/humidity?) but can be replaced fairly easily (similar tape to what is on the bottom side of a computer mouse).
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 11:38 AM
I don't know, but it's a good input, and it would surely make it much simpler to do this both now and as regular maintenance.

Through a very special form of telepathy, I've managed to have a glimpse at a Kawai service manual, but it expects a certain amount of knowledge of the reader, I think.
It mentions keyboard grease and has a few figures, but none of them refer to the WR action (even though it's from a CA-97 document) and for the WN action, they have red circles here and there. That's probably lubrication points, but then there are also black X's beside some of them, which could mean... don't lubricate?

Would you be able to chip in, James, regarding whether the capstan ends are to be lubricated? Your answer is yours alone and I won't and can't sue Kawai (or you, of course) if something goes wrong.

I know the obvious suggestion is to call the dealer and ask, and I'll probably end up doing that if I can't get the information here, but I doubt they'd readily know. They're dealers and acoustic technicians most of all (which is fine).
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 11:40 AM
And there's the answer, I guess. There is a small foam or felt pad (I can't tell) with something shiny on top of it. I googled ptfe tape and it appears to be very common and the same as what I have for making pneumatic connections airtight. Apparantly.

If you could confirm whether I can remove and insert the key later without having to pay attention to anything special, I think I'll give it a try,
Originally Posted by elendil
And there's the answer, I guess. There is a small foam or felt pad (I can't tell) with something shiny on top of it. I googled ptfe tape and it appears to be very common and the same as what I have for making pneumatic connections airtight. Apparantly.

If you could confirm whether I can remove and insert the key later without having to pay attention to anything special, I think I'll give it a try,


You can lift the hammer and remove the key. The only thing to look out for is that the hammer will drop to the keybed without the key there to support it, but you can fish it out easily enough (Kawai helpfully suggests using a magnet), but when I take out a single key I just stick a piece of paper under the hammer so it doesn't drop all the way down.

One recommendation (I believe from Lolatu) is to pay attention to the "grain" of the ptfe tape. You want to align the tape with the direction of travel/friction (front/back and not side to side) of the capstan.
https://youtu.be/yMpa43cNlJ0
Posted By: JoBert Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 12:24 PM
Originally Posted by mabraman

Very helpful video!
Happy to help wink
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 02:27 PM
Definitely. I found the problem. The felt and teflon are fine, but the capstan had some sticky stuff on it. I guess it must be from the teflon somehow.

Cleaning the capstan with rubbing alcohol made everything good again. Simple fix.

I'm considering cleaning them all and maybe re-applying a bit of grease to the points already greased, now that I have everything apart. We'll see.

Thank you, all.
Posted By: JoBert Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 02:58 PM
Good that you could fix it!
Be careful when applying grease, that you use the right kind of grease. I think I remember reading here on the forum that when greasing plastic parts (as I guess it would be the case here?) the wrong kind of grease can damage the plastic over time. (But I'm not sure if I remember that correctly.)
The grease ought not be a problem here. The grease problems date from the early 2000s, and those were cases where the key pivots were being greased (not necessary!), and the grease was not meant for the keys nor for that kind of plastic.

The plastic "business" parts of the action are of a different construction. They look and feel like nylon. Mine were greased when new, and were regreased several times since.

But it's moot here, isn't it? This was all about sticky goo on the capstans.
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 03:22 PM
Yes, the problem was sticky capstans, but I thought maybe it would make sense to regrease the hammer pivot point, since I've taken it off and on there and it seems a bit dry. The key works flawlessly at the moment, though, so maybe I should just leave it.

I've thought about grease damage as well, but ended up reasoning that it would have to be pretty strong stuff to damage the plastic. I'm no plastic, or grease, engineer though.
My gut feeling is ... if it works don't lube it.
I also think it wise to check with the service manual for information about where, what, and how to lube.
Perhaps your local tech can advise? Mine did.
I went looking for the CA97 service manual online. I could not find it, but I found the CS8 manual. The actions on these two are similar, so the information will likely apply to both.

Have a look at https://www.manualslib.com/download/1247604/Kawai-Cs8.html to download the manual.

On page 30 it gives information on "keyboard grease up".
There are areas for grease, and there are prohibited areas.
Have a look.
Adjustment and lubrication looks "challenging".

Maybe the CS8 service manual provides some assistance.

https://www.manualslib.com/manual/1247604/Kawai-Cs8.html?page=30#manual

Particularly pages 29-31 forward. Shows 3 specified lubricants (slip tape, let-off, hammer), hammer removal, grease points/prohibited areas, keystroke adjustment, keyheight adjustment, etc.

Not sure how you will source all the lubricants either. Not sure what random lubricants on the unidentified plastics and factory lubricants might do; perhaps if you fully cleaned off the factory lubricants you can estimate reasonable substitutes. Last thing you want is plastics reacting poorly to chemicals and crumbling a few years down the line (I've seen this happen a lot in other types of products).

edit - lol MacMacMacMac beat me again!
Posted By: lolatu Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 03:55 PM
I don't know if PTFE tape would work - as I understand it, it's used by plumbers for its chemical resistance, rather than its smoothness, so I'm not sure if the tape would be smooth or rigid enough. It might work, but I (and the author of mambraman's video, who looks like he followed my technique) used cutouts from a sheet of PTFE, which is readly available on eBay. I used 0.25 mm thick, but 0.5 mm would work too.

Originally Posted by MacMacMac
What action does Kawai recommend for such friction?
Once upon a time, KJ consulted with his peers and recommended teflon powder... Having imported a small pot of this from the USA, I can say categorically that it does not work! (Or maybe something was "lost in translation" and they really meant teflon tape. Interestingly, the Japanese words for "tape" and "powder" are transliterated as "tēpu" and "paudā", so maybe not.)
I would NEVER beat you.
Originally Posted by newer player
lol MacMacMacMac beat me again!
That's your wife's job. smile
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 05:12 PM
Thanks again for all of your suggestions. I think maybe you've scared me off of the grease for now. I'll do a quick clean-up of the capstans and put it back together. It's also less work!
Posted By: Andy R Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 06:47 PM
Originally Posted by elendil
Thanks again for all of your suggestions. I think maybe you've scared me off of the grease for now. I'll do a quick clean-up of the capstans and put it back together. It's also less work!


Note that the CS8 service manual warns against getting grease on the capstan.
Originally Posted by Andy R

Note that the CS8 service manual warns against getting grease on the capstan.


+1. It specifically says not to grease the action/capstan. Grease on this action is a specialized, very thick "friction grease" (think of the grease they use to get the smooth resistance on a manual SLR lens) and is only used in the action on the escapement simulation notch, nothing else (and definitely not on the hammer pivot).
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 01/28/19 09:24 PM
All buttoned up and working. I skipped the re-lubrication as suggested and all is fine. I never intended for grease to go on the capstans, BTW.

Thanks again for all of your help.
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 03/04/19 07:40 PM
Back to square one (or two or three).

The keys are sticking again. Something's obviously applying stickyness to the capstans and I can't see it being anything but the ptfe strip (or whatever's gluing it in place). It just seemed smooth and fine when I had it apart last.
Posted By: lolatu Re: Kawai CA-97 disassembly / stuck key fix? - 03/04/19 08:44 PM
Yep, I found the only solution was to put a new layer of PTFE on. Time to order yours on eBay!
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 03/04/19 08:45 PM
Throw me a link so I know what to look for.
Posted By: lolatu Re: Kawai CA-97 disassembly / stuck key fix? - 03/04/19 08:50 PM
https://www.ebay.co.uk/itm/Thin-PTF...m-thick/361806598951?hash=item543d5a9327
If the capstan is sticky, it's possible that the ptfe tape is sliding off its foam pad slightly, and the capstan is picking up some of the adhesive residue. I agree a ptfe tape replacement seems like the right fix.
A silly question: has anyone tried using a felt strip instead of the PTFE layer? On an acoustic action, the capstan pushes against a felt strip on the wippen heel. These can be ordered online from piano parts stores. Wouldn’t this approach be an alternative to the flimsy PTFE layer?
Posted By: lolatu Re: Kawai CA-97 disassembly / stuck key fix? - 03/04/19 09:22 PM
The Ravenworks people did that with felt strips for their customized VPC1, so it should work. You'd probably want to replace all of them though so they feel the same, which would be quite a job.

It might be a good idea for OP to try this plumber's PTFE tape first. It's generally much thinner (0.075 mm) than the sheet / double sided tape solution, so it might not work, but if it does it would be a slightly cheaper and more convenient solution for all the other CA-owners who need to do this in the future.
I'm a bit dubious about using PTFE thread seal tape. The kind I have is EXTREMELY thin and wispy, and it has a directional "grain" (don't know the right term) to it, like string cheese. You'd have to find an adhesive that sticks to it, and get it to sit extremely flat/smooth to the foam pad. Or wrap it around the key, and then the grain would be the wrong way so the capstan would quickly split and separate the tape.

Thin adhesive-backed strips used for computer gaming mice seem like they may be the better way to go? It's still dirt cheap, and can be cut to shape/size. This is the kind I got my MP11, but never had a need to use it.

https://www.ebay.co.uk/itm/PTFE-Teflon-Tape-Computer-Gaming-Mouse-Replacement-Feet-Sliders-Pads-Fast/191208383592?hash=item2c84e86468:g:Sn0AAOxyJypTlbvy:rk:1:pf:1&frcectupt=true

https://www.ebay.co.uk/itm/PTFE-Teflon-Tape-Gaming-Computer-Mouse-Replacement-Feet-Pads-Fast-Sliders-35x110/173811323480?hash=item2877f65258:g:QWMAAOSwkXdasXaR:rk:3:pf:1&frcectupt=true
The Yamaha GH series actions have a thin black plastic shim on the capstan equivalent.
It's thicker and sturdier than plumber's teflon tape.
It's about as thick as a standard 3"x5" card stock.

They need lubrication every couple of years.
I've not seen any sign of wear, and none have ever come loose.

I don't think they're teflon. They're not nylon either. But plastic of some sort.

[Linked Image]
Posted By: lolatu Re: Kawai CA-97 disassembly / stuck key fix? - 03/05/19 12:05 AM
Plumber's tape isn't sticky? (I've never done any plumbing. :\ ) Ah, forget that then. Yes those mouse feet might work well.
Originally Posted by lolatu
Plumber's tape isn't sticky? (I've never done any plumbing. :\ ) Ah, forget that then. Yes those mouse feet might work well.


The kind I have is just a reel of single-ply teflon (on some kind of plastic substrate I think), and it has to be extremely thin because you wrap several layers of it around pipe threading in order to ensure an airtight seal. It's thinner than those flimsy plastic bags you put produce in at the grocery store.
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 03/05/19 07:27 AM
Thank you for the link and all the suggestions. They unfortunately only ship to the UK, but now I know what to search for.

I'd rather not experiment too wildly.

I guess I could even ask Kawai, but I'm sure they'd charge an arm and a leg for it.
The typical plumbing PTFE tap does not have adhesive. It uber thin and designed to seal poor quality or slightly damaged threads that are suspect. This is useless for this piano application.

However, there are a variety of adhesive tapes made of PTFE and similar lower cost materials. This video has a good summary:

https://www.youtube.com/watch?v=YKzj7tWBFEg
Originally Posted by elendil

I guess I could even ask Kawai, but I'm sure they'd charge an arm and a leg for it.


You could try contacting them. I've bought parts directly from Kawai, and it wasn't exorbitant (but it depends on what they have stocked, and individual components like PTFE tape might not be warehoused).
Posted By: elendil Re: Kawai CA-97 disassembly / stuck key fix? - 03/10/19 09:53 AM
Which thickness PTFE should I purchase? Lolatus link has 0.25, 0.5 and 1.0 mm as a single package. From sellers who ship to Denmark, I can generally only find 0.5, 1.0 or thicker and not in the same package. Which thickness should I ideally purchase?
If I correctly understand the need ... I'd choose a thickness that is just stiff enough to retain it's shape while in operation, and no thicker.
Posted By: lolatu Re: Kawai CA-97 disassembly / stuck key fix? - 03/10/19 11:39 AM
I used 0.25 mm mainly (0.5 in some cases). The 0.5 mm stuff should work fine. I don't really know what the "ideal" is. 0.5 mm might even be better. I simply observed that the original PTFE is very thin and on a spongy substrate, so I went for the thinnest. However, I think the newest "grand feel compact" action replaces the pads with a solid block that wraps around the key (presumbably so it can't slide off), which I doubt has any sponginess to it.
Hi there!

I'm recently having this "sticky key" problem on my CA97

I investigated how to solve it, and seems to be a solution for it (as mentioned here) but I don't seem to find any information about how to disassemble the CA97 to get to the keybed...

Any clue on that would be appreciated.

Thanks,
David
Posted By: JoBert Re: Kawai CA-97 disassembly / stuck key fix? - 11/24/19 11:40 AM
This is from memory, after a couple of years, so a bit hazy: Start by removing the screws on the back, of the upper part, above the soundboard. Then you can lift off this upper part. I think there's a connection to the speakers for which you need to unplug the wires, but that's not difficult. Then simply continue from there. I found it rather straight forward to see which screws to remove next during each step.
Posted By: KevinM Re: Kawai CA-97 disassembly / stuck key fix? - 11/24/19 12:08 PM
Originally Posted by David Izquierdo
Hi there!

I'm recently having this "sticky key" problem on my CA97

I investigated how to solve it, and seems to be a solution for it (as mentioned here) but I don't seem to find any information about how to disassemble the CA97 to get to the keybed...

Any clue on that would be appreciated.

Thanks,
David


There was a mention in this thread that there is recall on Grand Feel. I don't know if that is correct but here is the mention http://forum.pianoworld.com/ubbthre...i-grand-feel-key-clinic.html#Post2913672

Might be worth investigating first up.
Posted By: JoBert Re: Kawai CA-97 disassembly / stuck key fix? - 11/24/19 03:07 PM
Originally Posted by KevinM
There was a mention in this thread that there is recall on Grand Feel. I don't know if that is correct but here is the mention http://forum.pianoworld.com/ubbthre...i-grand-feel-key-clinic.html#Post2913672

Might be worth investigating first up.

I don't know about the recall of the GF (if there is one), but the Ca97 has the GFII anyway...
There is no recall on the GF/GFII keyboard actions.

However, as always, if Kawai customers are experiencing any issues with the keyboard action of their digital piano (regardless of the instrument), it is best to seek assistance from their local Kawai dealer and/or distributor.

Kind regards,
James
x
Originally Posted by David Izquierdo
Hi there!

I'm recently having this "sticky key" problem on my CA97

I investigated how to solve it, and seems to be a solution for it (as mentioned here) but I don't seem to find any information about how to disassemble the CA97 to get to the keybed...

Any clue on that would be appreciated.

Thanks,
David


You will find there are metal corner brackets that hold the wooden case parts together. I suggest trying to leave the metal brackets in the piano, and unscrew only the screws that go into the piece you want to remove. Leaving the brackets in place helps prevent them from scratching things as they come out.

But as above, remove the piece above the soundboard. Then remove the wooden board with the speakers, unplugging and un-routing wires as necessary. It’s easiest to remove all the pieces at the top of the piano, and once they’re out of the way you can remove the fall board. It really is pretty easy and self-explanatory.
Thanks all so much for the advices, now I've checked the link where the several issues of the CA95 GF keybed are explained and well documented, I'll try to solve it by myself.. just need now the time and the little will smile
I have the sticky keys issue with my CA97. Took Kawai a few months but I finally had a technician call me tonight to schedule a repair under warranty. He said that he expects the job to take 8 to 10 hours because the tape on all 88 keys will have to be replaced. Sounds like a thorough job so no complaints from me other than the inconvenience of losing a weekend day.

My question is... will I have the same issue again in a few years when I am out of warranty? If that is the case, it might be worth it to sell it after it is repaired and pick up a CA99 w/ GF III...
If there's no indication that the new tape is any better than the old ... then maybe you're right to think of selling this piano.
Just my opinion.
Posted By: Maartin Re: Kawai CA-97 disassembly / stuck key fix? - 03/11/20 10:58 AM
Does the fact he wants to replace the tape on all keys and not just the affected ones imply there is a new 'fixed tape' which won't suffer from the same issue?
I currently have the same dilemma - my CA97 has a few 'scraping' keys and a few very mildly sticking, so I have a choice of whether to try and get it repaired or trade it in for a CA99.
Originally Posted by Maartin
Does the fact he wants to replace the tape on all keys and not just the affected ones imply there is a new 'fixed tape' which won't suffer from the same issue?
I currently have the same dilemma - my CA97 has a few 'scraping' keys and a few very mildly sticking, so I have a choice of whether to try and get it repaired or trade it in for a CA99.


I had 3 repairs made on my CA65 whilst it was under warranty. Two months ago I had all of the slip tapes replaced by a service engineer and the piano now performs very well.

Interesting, the guy who did the repair (who I now know quite well!) told me that the replacement slip tapes are now very different from the ones they first used on GF I actions - being much bigger (hence larger surface area) then they originally were. I'm keeping my fingers crossed and I will hopefully upgrade my piano before the problem reoccurs.
I wanted to give you guys an update on my repair. The technician came a week and a half ago, and really did spend 8.5 hours replacing the slip tape on every single key. He was an older gentleman and worked pretty slowly.

However, the repair came with a few issues so my piano is still not fixed:

1) He broke the hammer on the last key, and he said he ordered a new one and have to come back to finish the job when received.
2) Another key's action is not performing properly. The key is set lower than the rest, travels less when pressed down, and there is no bounce on the key when you let go.
3) The keys are no longer perfectly even, and there is variation key to key on height.
4) The piano is not put back together (at my request since it took him about an hour just to open the case, and I don't want him to spend an extra hour when he returns).

The key height variance really bothers me. I wrote Kawai US about the issue and hopefully they can take care of me, but just beware if you get your piano worked on. The repair technician works mostly on digital instruments and equipment, so I'm not sure what he knows about setting key height.

Here are some pics:
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So now we're almost in June, and Kawai has been silent on my piano. I last emailed them on April 12 and there has been no response that they will take care of this when everything opens back up post COVID. I chased again, to just ask if this is on their radar. I really hope they stand behind their product and warranty.
Dave, I will send you a PM.

Kind regards,
James
x
I feel for you man. KAWAI left me high and dry after several ‘slip tape’ replacements. Mines still under warranty but I’m not letting any of their techs touch my piano ever again. (Well, they said they can’t anyways due to C-19)

I found a great slip tape replacement at McMaster-Carr and since you seem mechanically inclined let me know if you have any questions. I’ll do my best to help.

Actually , I’m taking the piano apart this weekend as 4 more keys are stuck. I guess ultimately I should dump this piano but I’m not quite ready to do that yet. I should ALSO replace EVERY piece of slip tape but that will take quite some time.
Seems like this problem is not an isolated one... I believe they fixed this faulty design with the slip tape in the CA79/99 at last. It's odd that the key leveling was messed up after replacing the slip tape though. Key leveling is done through the center pin felt washers. On the other hand, the hammers push the rear part of the keys through the capstan, hence through the slip tape. If that tape is too soft or something, it can add some variance to the level of hammer pressing on the key and lead to this irregularity. It's a tricky situation and I wouldn't mess it up further with the center pins. I'd rather request from Kawai a replacement, provided the piano is still in warranty.
That's a wavy set of keys!
Originally Posted by newer player
That's a wavy set of keys!

Agreed. I do not know how this happened, but I'm trying to reach out to DaveCSparty for more details about the technician's visit etc.

Hopefully he returns to this forum before too long.

Kind regards,
James
x
It sounds like the regulation/repair isn't done yet. Just as with an acoustic piano, the Grand Feel action uses paper punchings on the balance rail to regulate the final key height, I would imagine this is the final step after fixing the hammer and the slip tape.

Most likely the tech hasn't done it yet because there is still more work to finish up first, but it would be good to confirm with him that it needs to be done before he closes the unit back up.
Originally Posted by Gombessa
It sounds like the regulation/repair isn't done yet. Just as with an acoustic piano, the Grand Feel action uses paper punchings on the balance rail to regulate the final key height, I would imagine this is the final step after fixing the hammer and the slip tape.

Most likely the tech hasn't done it yet because there is still more work to finish up first, but it would be good to confirm with him that it needs to be done before he closes the unit back up.
The height of the keys shouldn't change if you change the capstan tape. On a real piano the leveling is done be attaching weights in the rear part of the keys with the action removed. The weights will simulate the weight of each hammer and whippen to the capstan and hence the rear part of key dip into the felt beneath the keys. Once leveled, this won't change unless the hammer weight is changed and is pressing the corresponding key more than usual, so the rear part will dip more and consequently the front part will stick up above the other keys. If only changing the slip tape between the capstan and the hammer caused this irregularity, then something is very wrong, although I don't know what.
Originally Posted by CyberGene
If only changing the slip tape between the capstan and the hammer caused this irregularity, then something is very wrong, although I don't know what.

I assume the tech has to remove all the keys in order to perform the tape replacement, and who knows if he removed the punchings as well (though on my MP11 only one in every 3 keys or so needed punchings, it was nowhere near as bad as OP's). The hammer capstans sit against the slip tape at rest, and if the tape height is different, the keys may sit differently. I recall the capstans are adjustable for this very reason. Something is definitely awry here, but again the job isn't done and I would want to see the final regulation before calling it botched.
The punchings are very lightweight paper and come out very easily. Kawai sent someone to work on my piano once and I found punchings all over the place - when you pick up a key there's a good chance a punching comes with it.

Straightening out the keys with punchings is not difficult but it takes a long time, and you need to have a few different thickness punchings which you can get from any piano parts supplier.

Hopefully the technician knew enough to NOT TURN THE CAPSTANS - thats another way to change key height but accomplishes something very different. If he did you have another adjustment mess on your hands.
I talked to a guy at Kawai Service department and he said there have been changes to the slip tape. The older versions actually used felt under the tape. I don't know if there have been iterations in the rubber/slip tape combination - I hope so. Mine's getting fixed next week, I'll see what I can learn. The technician who's doing my piano has done slip tape repairs before so I'll talk to him about it.
Good luck with that . I hope it works out. I finally found time to take my CS10 apart today to fix 6 more stuck keys.

I have an excellent slip tape replacement from McMaster-Carr (great name right? Since that’s exactly what the tape DOES! Either the whole piece slides off to one side or another or the little Teflon upper layer starts to separate and slip off). I’ve had a tech come over to my place several times and replace every keys tape and the problem has always persisted.

To my knowledge, and from what I can see, they’ve used the same tape every time. The tape is a BAD design. The stuff I found has none of the issues that theirs has. When I took her apart today none of the tape I used (I’ll find a link to it and post here tomorrow) If I forget please feel free to PM me. I can’t take credit for finding the tape as I have a materials expert friend who designs products for hi-tech companies and he gets all the credit for sussing this out.

When I looked inside today the new tape I used months ago was in excellent condition and hadn’t moved from the key. FIRST, the tape needs to STICK to the key. SECOND it needs to not separate from itself or the adhesive that’s holding the upper Teflon slippery part will seep out and stick to the little brass rounded head (looks kind of like the head of a round tack) here’s a video showing the area here:

https://youtu.be/pzHZgjhbFS4

The gentleman in the video uses paper to fix his issue but I wanted to go with a solution that would be more permanent.

I had the head tech come over after many frustrated bad fixes from others before him and when HE looked at what they did he said they did a shoddy job. But he also said something that in my opinion is bad advice when using KAWAI’s tape. He said the tape has to be cut as close to flush to the key as possible. Now, since their tape is inferior and the Teflon separates over time , if it’s cut FLUSH to the key then the adhesive that seeps will get onto that little rounded brass area and cause your keys to stick quicker. If the tape is cut a little oversized and the Teflon separates and the adhesive seeps then there’sa better chance that the adhesive may not reach the brass part and cause the keys to stick. The best solution is DONT USE THEIR TAPE!

I HAVE noticed that it is almost ALWAYS your most used keys that get this issue. (Imagine that)

My solution was, even though the piano is under warranty, (doesn’t matter at this point though as no one wants to come over as they claim to have no access to the warehouse and of course we have the Covid issue), was to find a superior tape that doesn’t need replaced.

I DO play the piano a LOT and if your not an avid player you should experience fewer issues (hopefully!)

If I were you I would make SURE the tape they are putting on this time around IS NOT their usual. And, if it’s NOT, ask them what it is that makes it improved. Keep track of the keys repaired and see if the same issues come back later.

After taking my CS10 apart for the 4th time we are seeing a few other design issues that are rather shoddy and are going to remedy those next week. That will just make taking it apart a lot faster and efficiently.

Overall, we are very disappointed in KAWAIs service but we do love their product (overall) .

We just need to find the time to replace ALL 88 keys with the new tape (YES, it is very time consuming).

Let us know how it goes!
What did you use between the wood key and the ptfe tape? Did you re-use Kawai’s foam?

The new Grand Feel 3 has a different design, looks like they went away from slip tape.
Joe, I'll try and remember and update my post above with the part number and link Monday to the McMAster-Carr item.

The ptfe tape is permanently mounted to foam. The foam is stickyback and available in different densities and thicknesses. We just picked something close to Kawais in terms of thickness but went a tad denser.

An old timers prop effects trick (if you want that tape to REALLY hold onto the wood) is to mask the key and lightly spray the area with spray 77 you are using the sticky back on and it will REALLY hold. At least the tape won't slip. The problem with the design and there are a few! is that the little rounded tack area is never really CENTERED over the slip tape so as it keeps hitting the tape its PUSHING the tape to one side or another. I'll be glad to be rid of this piano one day and would NEVER invest in another KAWAI due to lack of support/inept support. I could not even in good conscience sell the piano knowing the design flaws.
The tape we used is from: https://www.mcmaster.com/catalog/126/3677

Its item #76475A18

It is just a High-Bond Low-Friction Tape Made with Teflon® PTFE.
Wow! $19 for one foot of 1" wide tape!
Yes sir, don’t track the expense, Instead, track the joy and benefit the tape will bring you.
Posted By: Mickey_ Re: Kawai CA-97 disassembly / stuck key fix? - 06/10/20 08:58 AM
Best. Comeback. Ever.

Thanks for the laugh, Terry!
This thread is in serious need of a 'Like' button!

Thanks Terry!
Hi all,

I've repaired my CA97 several times, each time different keys..

While watching a CA99 review, the guy mentioned that they were retrofitting any GF2 actions with genuine felt like in acoustic pianos before they sold the piano, because of the very problem mentioned in this thread. That resulted yet in an presumably better repetion..

Minute 13:40

https://www.youtube.com/watch?v=QoS2ghGCgCg

My question is, any thoughts or guesses out there about what that felt exactly is? I'm willing to repair all 88 keys from scratch but this time hopefully with a definite solution.

Regards,
David
That’s very interesting. I wonder why the felt gives a better repetition speed. I think we will try a few keys on the CS-10 and see what it feels like vs the new slip tape were using to replace all of our failed KAWAI ones.

Today we took her apart again! It’s getting quite tedious but we’re improving this piano with EVERY disassembly! Next we’re going to cut down on removing the back sound board by incorporating a piano hinge and quick disconnect lock for release. (Oh the irony using a piano hinge...).

Since NONE of our McMaster-Carr Teflon (slip tape) has failed we are quite happy but sooo many other keys need replacing. I’m thinking of hosting a slip tape assembly line party to kick this in the arse. So far I have 2 sound engineers onboard and one product design specialist. Curious to see how fast but accurate we can bang it out.
I'm tremendously interested on what the results will be like.. I'd really appreciate your feedback on whatever improvements and actions you took on your CS10 since we share same key action I guess..

I've ordered some felts and a foam tape to try them out on my CA97 and see whether any of those do the trick so I replace the pads on all 88 keys, but it will still take some weeks to arrive.


Meanwhile, I'd love to know what the guy on the video was meaning when he said the natural felt like in acoustic pianos, I'd immediately buy the same if he advised and I'd replace it in mine.


Good luck with your attempts!

Regards,
David
I talked to a product specialist/materials expert friend today and mentioned this thread. He’s also really knowledgeable when it comes to physics. (He has that unfortunate job where he has to tell potential inventors why there idea won’t work because we have physical laws we all have to abide by. Things like gravity!)

Anywho, he looked at that video and doesn’t understand why the felt would result in better repetition vs the Teflon tape. The felt is , hmmm, how do I describe it, ‘soft and mushy’ and the tape in his opinion has a surface that would allow better repetition for playing. It’s one of the reasons he selected that particular McMaster-Carr replacement.

I’m not sure how much stock I would put in that video as the main issue with Kawais slip tape is not even really described properly in the video. The issues with their tape is 1) it doesn’t stay put and 2) the top Teflon part slides off from the foam part leaving the adhesive exposed and that’s bad because that little brass round tack head part starts to stick to it. Sorry for my horrible parts description. I need to learn the names of the piano action parts to sound half intelligent. Lol.

But sure! I’d love to try some felt but as you say you would have to settle on a felt. It would need to be the right thickness, density and very durable AND it would need to stay put.

I’m like my product specialist friend and believe EVERYTHING needs to be ‘mechanically fastened’ to stay put. Obviously you can’t do that with everything but what that means is we are VERY weary of anything that uses a double sided tape adhesive to it. Usually, the adhesive fails on one or both sides. To get around THAT, he has a cool trick where he uses spray 77 on the surface that he is attaching the part that has the double stick tape on it and IT REALLY WORKS! It’s very tedious and takes time and usually involves masking off areas you don’t want the spray 77 on.

He’s already told me that when he speced the new Teflon tape for me I should be removing the old slip tape, gently sanding the part (the wooden key) that the new tape will go onto to remove ALL remnants of the old adhesive and then masking each key and spraying it with 77 BEFORE applying the new tape. Yeah, it’s a LOT of work and I’ve only done 20 keys so far! But I’m very happy with results and have had zero failures. But to do ALL the keys will take probably (assuming 3 people assembly line fashion) maybe 12 hours?
Originally Posted by Terry Michael
I’m like my product specialist friend and believe EVERYTHING needs to be ‘mechanically fastened’ to stay put. Obviously you can’t do that with everything but what that means is we are VERY weary of anything that uses a double sided tape adhesive to it. Usually, the adhesive fails on one or both sides. To get around THAT, he has a cool trick where he uses spray 77 on the surface that he is attaching the part that has the double stick tape on it and IT REALLY WORKS! It’s very tedious and takes time and usually involves masking off areas you don’t want the spray 77 on.

He’s already told me that when he speced the new Teflon tape for me I should be removing the old slip tape, gently sanding the part (the wooden key) that the new tape will go onto to remove ALL remnants of the old adhesive and then masking each key and spraying it with 77 BEFORE applying the new tape. Yeah, it’s a LOT of work and I’ve only done 20 keys so far! But I’m very happy with results and have had zero failures. But to do ALL the keys will take probably (assuming 3 people assembly line fashion) maybe 12 hours?

Hi and thanks for your thoughts, I'm really excited about your findings, it would be great if you shared some photos and links to the used felt and materials, so we all can benefit of your experience.. (if it helps, the actual cushion currently present on the keys is about 1mm thick, not more, but I guess that's something that eventually can be altered)..

Replacing felts on all keys are presumably taking 7 to 8 hours as per Kawai technicians, so make sure to put some good music and order some pizza during the break smile

Good luck and let's know whether succeed at the job!

Regards,
David
Originally Posted by Terry Michael
I’m like my product specialist friend and believe EVERYTHING needs to be ‘mechanically fastened’ to stay put. Obviously you can’t do that with everything but what that means is we are VERY weary of anything that uses a double sided tape adhesive to it. Usually, the adhesive fails on one or both sides.
I don't see why Teflon needs to be used in this application. Other high density plastics may perform nearly as well and be easier to apply & safer.

One could find/mold a lightweight cup that slides over the key end (inspired by Kawai's GF3 fix). That cup could be mechanically fastened with one wood screw (carefully drill the key far from edges, pour some wood adhesive in the hole, install the screw). Molding the plastic would be expensive, there is a risk of splitting the wood with the screws, and there may be a weight penalty.
____

FYI - Ski binding makers figured how to adhere rectangle teflon pads reliably a few decades ago. These pads suffer physical abuse and extreme temperature swings. I would guess some of the tricks:

- The teflon was typically adhered to a high density, smooth plastic surface (maybe delrin).

- The smooth plastic surface typically had a depression of c. 1mm (or more). That "tray" might have provided some mechanical restraint. It might have been just to help the assembler position the pad. Some of these trays were slightly oversided, so maybe provided a secondary mechanical restraint if the pad started to slip. Some of these trays seemed high tolerance.

- It appeared some pads were self-adhesive whilst others had a blob of glue underneath

One could use this ski binding to inspire piano fixes.

- Find smooth plastic rectangle trays with the right sized depression
- Apply self-adhesive teflon rectangle that tightly fits the depression
- Adhere the plastic tray to the wooden key

** If you can't find a generic plastic tray on alibaba, molding trays would be very expensive

**The plastic tray needs to be fastened to the wooden key. One option is for the tray to have 2 wings which accept wood screws. Then drill the wood key, add some wood glue, and carefully install 2 screws.

---> Screws at the end of some keys would likely split the wood

**Alternatively, skip the plastic tray, drill holes in the Teflon. Drill holes in the wooden key and fill with wood adhesive. Fasten the tray with two screws and the self-adhesive. I don't know if any of the self adhesives will work well on wood, particularly rough surfaces. You still have the problem of wood screws splitting the ends of the keys.

** Alternatively, skip the plastic tray and the screws; strap the teflon on the wood key. That might require notching the teflon to prevent movement.

These ideas all have risk of breaking wooden keys, weight penalty, time consuming.

Also teflon may be a very dangerous material so research that. I would particularly avoid drilling or cutting it in a domestic environment and leave that to the professionals with proper health & safety protocols. Out of an abundance of caution, I avoid touching or cooking with teflon.

[Linked Image]
Teflon is harmful???
Originally Posted by MacMacMac
Teflon is harmful???

https://www.democracynow.org/2018/1/23/dupont_vs_the_world_chemical_giant
I would not use it on any of my cooking utensils. And I would wear a mask (respirator/organic vapors filter) if I were spraying it or using it for mold release. But I think it’s safe on one side of a piece of tape.

http://m.fjbluesea.com/info/is-ptfe-tape-toxic-31607323.html
David, I’ll try some felt the next time we open up the CS10. I’m VERY curious to see if how it affects repetition speed!
Teflon is perfectly safe as long as you don't heat it past 500F. Dupont got sued because the chemicals used to make it are nasty, but the end product is very inert.

I don't know if Teflon is the best material to use for this pad though, because its wear resistance isn't great and the brass capstan puts high localized forces on it. A more wear resistant plastic like UMHWPE might be better, and you could use molybdenum or tungsten sulfide to reduce friction further.

While the action is apart, I would personally go cut down some of those weights. The GF1 and GF2 keyboards are WAY TOO HEAVY even with well-lubricated pads.

My own CA95 has wavy keys and lots of sticky ones too. I've lubricated and glued some pads back on, but haven't bothered replacing them yet because I use the ultra-heavy high-friction keys as a practice aid. If I knew it was going to be this annoying though, I would've bought a Roland LX706 instead. I abused my old Roland FP-7F's keyboard for around 4000 hours and it played like it was brand new. I can't say the same about my Kawai, though the GF3 equipped CA99 I tried in the store admittedly felt much much better and probably has fixed the problem.
This is what I had read long ago ...
Originally Posted by trigalg693
Teflon is perfectly safe as long as you don't heat it past 500F. Dupont got sued because the chemicals used to make it are nasty, but the end product is very inert.
But birds are very susceptible to the fumes emitted from teflon cookware, especially on first use. These items are instant death for any bird nearby.

Fortunately the days of such teflon coatings are long past.
Hmmm. I just checked McMaster-Carr for sticky backed FELT and Wow! They offer sooooo many kinds in so many densities and thicknesses, it would be quite a long term experiment to see which works best.

I’m VERY happy with the High-Bond Low-Friction Tape we used to replace that awful tape that comes with the piano so I think I’ll stick (no pun intended) with it!
You know... there is one thing you CAN do though if your really into the felt replacement. Check out this link. It’s an education on felt used in pianos.

http://www.stevespianoservice.com/O...lt-action-felt-damper-felt-and-tools.htm

You could call the guy and tell him what your trying to do and he may even sell you felt that he has. Or at the very least recommend a density.
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