Piano World Home Page Forums Our Most Popular Forums Digital Pianos - Electronic Pianos - Synths & Keyboards Kawai CA-97 disassembly / stuck key fix?

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.

Very helpful video!

Happy to help

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.

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.

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!

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.

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.That's your wife's job.

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.

+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).

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.

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.

Yep, I found the only solution was to put a new layer of PTFE on. Time to order yours on eBay!