Opening and Cleaning the PX-5S (or, The Comprehensive Guide to Voiding Your Warranty)

[craZivn]

First off, this will void your warranty. However, my keyboard is out of warranty and I experienced the A sharp key going a little velocity-indiscriminate again. Here is what I did to clean the contacts and restore it back to original performance:

 

Step 1: Read this guy's thread. His board isn't a PX-5S but pretty much everything he says still applies, the internals are similar.

 

Step 2. Assemble the required tools:

#2 Phillips screwdriver (you will definitely want one with a magnetic tip!)

#1 Phillips screwdriver

Cotton swabs

Electronics cleaner or electronics-safe solvent

Small flat screwdriver or pick

Paper clip

Small flashlight

 

Some things to take note of before starting!

 

1. There are three face panels (battery compartment, slider/knob bank, center section) but I lifted them off as one piece since they were sort of held together by the blue felt strips.

2. All the screws are the same EXCEPT for the three internal keybed screws, which are easy to tell apart because of their distinctive heads. And also the little screws which secure the access panels, which are distinctive because they're a different size.

3. Since all the screws thread into plastic, it is imperative that you install them carefully and set the threads properly so as not to damage them. I made a short video on how to set the threads here:

 

 

4. Once you remove all the screws, the keyboard will be "loose". Leave a few in the rear bottom edge to keep everything together while you roll the keyboard upright. Then lift the edge of the keyboard and remove them. (I didn't think to do this.)

5. A bed makes a great work surface for this operation.

6. You will need a magnetic-tipped screwdriver to reinstall the inset screws behind the access panels. If you can't get one, use a bit of sticky grease to hold the screw onto the driver when you install.

7. When re-installing screws, be careful not to over-tighten!

8. When reassembling, be careful not to pinch any wires in the process. The battery compartment feeds are especially in a vulnerable spot so just keep an eye on them when you're buttoning everything up.

9. The names for various parts that I use in the captions are made-up by myself, so if you go looking for a Casio part using the terms from these pictures, you probably won't find what you're looking for.

10. If you break something, you could be in for a greater expense than if you just took the keyboard to a service center in the first place! Operate at your own risk.

 

On to the pictures:

 

 

Forgot to mention, re-install key retainer after the keys are back in!

 

 

 

Hopefully this is useful to someone, if there are any questions or if some of the pictures are confusing please let me know. Merry Christmas!

 

Ivan

[Jokeyman123]

Excellent layout, much more detailed than I had the patience to put together.  Then again, I din't have too many good brain cells left after trying to figure this out in the first place! And there are important variations to the PX5s vs. PX350 as you clearly show. Glad to see I'm not the only one who decided this was a doable project. Mine is still holding up well, was worth the trouble to make it more playable. But then, mine was not under warranty and I had done teardowns on many other keyboards, some successful, some not. Not looking forward to having to do this again, but I would if the keys were worth it. Also ramped up the padding on an older PX575 with similar action as these. also successful, the Casios are much easier to work on than say for example the Kurzweils or Yamahas with piano actions.

[craZivn]

Thank you! If it hadn’t been for your original thread, I almost certainly would have broken something taking mine apart. Your pics and descriptions are what gave me the knowledge (and the courage!) to attempt this operation, now I wouldn’t hesitate to do it again! 

 

Hopefully the next guy or girl who does this will have some more pointers to add, and the repair/mod knowledgebase can keep expanding.

 

Regards,

Ivan

[Coffee]

THANKS A LOT! 

Hmm Capxon capacitors. I wish the PX-5S had Japan caps.

[craZivn]

UPDATE: I realized that Step #5 failed to mention the two oddball sunken screws near the ends, updated the #5 picture to correct that mistake.

[JohnMO]

Wow. I appreciate the detail of this post. I landed here because my E3 was out of whack (sounded inordinately loud, even with a light touch) and my efforts with compressed air did not resolve the problem. However, seeing the location of the sensors in these photos enabled me to better target my air blasts and voila! Problem solved. I am thanking my lucky stars, too, because I know that even with the help of this nicely illustrated process I would have screwed something up.

[Knuckles]

Amazing post. I am probably going to need to have a go at doing this. These pictures are going to be priceless for me. Thank you so much for posting them! 😍

[craZivn]

Thank you all for the kind words! I have a quick update: I have found it to be easier to disassemble the keyboard while it's on it's stand. That way I can access the top and bottom without having to roll the keyboard over.

 

 

I've also modded the rubber dome strip as detailed below. Although I can't recommend it yet since I want to give it more time, this is what I did (copied from my blog at crazivn.com):

 

"    Addressing the Bb Velocity Issue:

   If you're here, you're probably already familiar with this issue so I won't go into detail describing it. Cleaning the contacts works well, but the problem will undoubtedly pop up again and most of us don't have the time to pull the board apart every few months to re-clean them. 

   I have a theory that the reason the issue affects this particular key (although it can pop up with adjacent keys also) is that the rubber dome strip doesn't fit flat to the PCB at this point. The rubber dome strip bridges a gap in the PCBs, and the spacing isn't quite perfect so the strip has a slight "wave" to it. This allows moisture to get underneath and contaminate the contact points.
 

   My potential solution was to cut the rubber dome strip, and remove a little bit of material from one of the cut faces to allow the strip to rest flat. However, it should be noted that this will allow the cut ends to "flop" due to the spacing of the mounting dowels on the rubber strip. To secure the cut ends, I used a drop of hot glue on the front and back.
   Make sure the hot glue goes around the top of the rubber, and underneath the bottom of the PCBs to form a sort of "I" shape. This will harden into a sort of clip to hold the rubber to the PCBs. This technique is necessary because hot glue won't adhere to the rubber.
 

   Time will tell if this solves the moisture issue.  "

 

I can't recommend that anyone cut their rubber dome strips (I'm still giving the mod time to see if there are negative consequences) but that's the story so far. Also, I have a complete spare keybed on hand so I do have a safety net in case I destroy components.

 

Ivan

[craZivn]

UPDATE: The moisture issue is back! Here's what I tried this time, will update again if the issue returns. (copied and pasted from my blog at www.crazivn.com.)

 

Update 2019-01-04:

   The Bb issue is back! This time I am of the opinion that it's not condensation collecting as I suspected before, but that the factory-applied grease may be breaking down and the oily residue making it's way underneath the silicone dome strip via capillary action. 

   I replaced my chopped dome strip with a new one, and this time, to eliminate the "wave" in the strip, I decided to move the outer PCB a little bit to the left to widen the gap between it and the center PCB, thus taking up the slack in the dome strip and forcing it to lie flat. 

   First I disassembled the PX5S and removed all the keys over the left-side outer PCB. Then I removed the seven screws which secured the outer PCB. 
 

   The outer PCB is aligned in position by a small tab on the plastic chassis, which nests into a notch on the PCB to register it. In order to shift the PCB outward, I cut this tab off with nail clippers and smoothed the remains by shaving it with an X-Acto knife. 

   Here is the tab before I cut it off. 
 

    When I lifted the PCB off of the plastic chassis, I noticed an oily trail that had collected underneath the PCB. I suspect that this is a separation from the factory grease that was used to lube the key pivot points. 
 

    Just for fun, I installed a cotton ball in the space between the PCB and the plastic chassis, underneath the gap. The theory is that any further seepage will be collected by the cotton rather than allowed to creep up over the PCB and under the dome strip. Whether or not this will have any effect remains to be seen. 
 

   In order to shift the outer PCB to the desired location, I had to remove a bit of material from the inside of the screw holes.
 

 

 

   Here you can see the original location of the registration tab that I cut off to shift the PCB. (Outlined in blue.) 
 

   
   With the PCB shifted over, the dome strip can now lie flat with minimal ripple. Hopefully this will prevent the oily residue from contaminating the contacts. 
 

 

[Tom Williams]

All I can say is "Bravo!"

[Jokeyman123]

Just one more comment for anybody who attempts this-be very careful that you do not get anything! except possibly a little damp clean water on the carbon contacts-these are so easy to contaminate-as this post is describing-no chemicals, no nothing. I learned this the hard way and yes this grease can cause grief-I am surprised it was only one key. these rubber domes are usually very tightly sealed on top of the internal contacts, unfortunately by playing this seal can become open to contamination. and i would also be very careful cleaning the IC board traces under the rubber. After trying several things-most of which will leave enough residue to really foul things up, I reveted to just plain damp lint-free cloth with a little water, even isopropyl (rubbing) alcohol can leave residue and cause these traces to not connect with the carbon contacts. I know, I've done that. If you use alcohol, make sure you wipe off the residue after it dries. If you don't believe this, put some on clean glass and see what it looks like.

[Dave Schreier]

I should thank you craZivn for the instructions and pictures - A few months ago I had one key - lowest Ab as i recall - go berserk.  It took about 4 - 5 hours for me to do this, and it worked - thanks again.

[craZivn]

You're welcome Dave!

 

Quick update: The Ab5 key started doing the same thing so I disassembled the keybed and moved the circuit board, and gave it the cotton-ball implant like I did with the other circuit board months ago. I also took the opportunity to remove all the keys and rubber dome strips and give the contacts a thorough cleaning.

 

The Ab2 key, which was the one giving me issues before, has been problem-free since the last operation with the circuit board and the cotton ball, although I did notice (and clean off) a little more of the grease residue beginning to creep along under the rubber dome on a couple keys.

 

I think the only permanent solution would be to clean out all the factory grease from the pivot and slide points, and replace it with some type that is more resistant to breakdown. Perhaps you fellows over at Casio should consider switching to a different grease in the keyboard's assembly? I'm not knowledgeable about greases but it seems there must be something available that won't separate over time. Aside from this issue I've had almost no problems with this keyboard, it's a workhorse in the studio and an absolute weapon on stage to a cover-band player like myself. It's just an inconvenience to have to disassemble and clean it because of an issue that really shouldn't be there.

 

Ivan

[Jokeyman123]

Again, amazingly detailed work-mu PX350 been good for several years now, and I just did a similar mod to my PX560-also purchased 2nd hand and it needed it, not as sloppy with the grease but keys were too clacky for my taste-the construction is similar internally.  Just posted a CTK6200 breakdown here if anybody needs that. I would agree that a different type of grease, or at least keeping this to a minimal amount would be better. The CTK6200 had this all over-I made sure to clean excess, which was everywhere. I found no contact contamination, but then this one hasn't been played much from what I can see (I acquired 2nd hand) and I'm sure in time the excessive grease would creep into the keybed contacts, especially if in a warmer environment.  

[bob green]

I'm on my SECOND Px5S exhibiting this Bb issue, and honestly as much as I love the instrument if I knew I was purchasing a project(s) I might have looked elsewhere.....

[Casiofun]

Wonder if temperature extremes cause the issue with the grease running. I would think heat would be the culprit playing outdoors in hot environments or in hot auditoriums with bright lights. Dust can also cause this issue so keeping the board covered when not in use would help.

[craZivn]

1 hour ago, Casiofun said:

Wonder if temperature extremes cause the issue with the grease running. I would think heat would be the culprit playing outdoors in hot environments or in hot auditoriums with bright lights. Dust can also cause this issue so keeping the board covered when not in use would help.

 

It could definitely play a part, but I live in Wisconsin and my studio is usually around 65-70 degrees Fahrenheit so definitely not extremely hot here. I occasionally play an outdoor show where it gets up near 90 though but nothing that should cause good grease to separate.

 

Ivan

[Zanna Zabriskie]

Hi Ivan, what about to seal the space between the edge of the ribbon and the PCB with hot glue or a good tape? To prevent infiltrations of grease or something, I say.

Just another thing... where did you buy the strip?

zz

[Zanna Zabriskie]

Ah, by the way, the "definitive" solution to clean contacts:

Clean baby, clean...

 

After this, you will never need to clean your contacts again.

zz

 

[craZivn]

On 12/30/2019 at 11:04 AM, Zanna Zabriskie said:

Ah, by the way, the "definitive" solution to clean contacts:

Clean baby, clean...

 

After this, you will never need to clean your contacts again.

zz

 

 

I think those instructions are for cleaning metal switch contacts, I'd be afraid to let anything with a five-dollar name like "Carbon Tetrachoride" near my keyboard!

 

I don't think it's feasible to seal the ribbon, there are very shallow air channels in the ribbon to allow air to move in and out of the contact domes since they need to collapse when the key is pressed and then pop back up when it's released. So unfortunately they must be allowed a little exposure to the outside world in order to work properly.

 

I got my extra strip from an entire spare keybed that I bought on Ebay some years ago. One of the keys had broken in the bed so I bought it for parts at that time. As far as I know there's no "official" source for parts directly from Casio (although someone may correct me on that) so maybe keep an eye on places like Reverb or the 'Bay for keyboard part-outs.

 

Hope this helps, happy New Year!

 

Ivan

[Jokeyman123]

Carbon tetrachloride-AKA cleaning solution-the source for Superfund sites in the United States as this is what clothes cleaners and tailors used for dry cleaning until it was banned here in the US as an incredibly toxic chemical known to cause cancer. I would not recommend anybody use this for anything. I'm not sure it is even available anymore through typical vendor channels or retail.

 

https://www.atsdr.cdc.gov/phs/phs.asp?id=194&tid=35

 

https://www.fishersci.com/shop/products/carbon-tetrachloride-99-acros-organics-2/AC148170010?gclid=EAIaIQobChMIhrfqlNHx5gIVDJyzCh1W2A3EEAAYASAAEgIgUPD_BwE&ef_id=EAIaIQobChMIhrfqlNHx5gIVDJyzCh1W2A3EEAAYASAAEgIgUPD_BwE:G:s&s_kwcid=AL!3652!3!280010633976!p!!g!!carbon tetrachloride

 

I used this years ago to clean grease from linotype machines before it was banned (yeah i did that working my way through college between gigs)  and it had skull and crossbones on it-one strong whiff could put your lights out and it always gave me a headache. Always had huge ventilation fans going, this stuff was deadly-I still worry I destroyed something from inhaling this years ago! If you clean the carbon contacts inside your rubber strips with anything other than plain distilled water, you will contaminate their conductive qualities and ruin them. Even a tiny hair or speck of something can cause a key to go dead or malfunction, why these rubber strips are sealed so tight initially from the factory. A few keyboards I've disassembled had some kind of glue adhering the rubber strips to the IC boards-what a nightmare to get those off and back on tightly again-I think Roland keys were like this. if you don't believe me, well you are on your own. I've done it before i knew better, I know from experience what not to do...now! As far as grease inside these keyboards, I really wish there wasn't any-I've had many other keyboards apart that had none, and were quiet and worked properly. there should be no need for this, if the assembly is mechanically sound, no offense to Casio, not the only company that does this.

[Zanna Zabriskie]

Ahahah!! But I was joking, I thought it was clear! An army technical manual dated 1954.... The "definitive solution"... But I'm sorry if it wasn't clear enough, my fault.

 

I have a question for you all: how do the sensors work?
Are the contacts in the rubber strip ON/OFF contacts? If yes, how does the piano feel the "touch", the speed, to play piano/forte?

 

The reason of my question: my issues are with 6 keys, but only black keys. I saw a lot of people having problem with black keys too. A strange thing, because for dust and moisture all the contacts are the same ... So i'm asking himsel if there is another kind of problem.
 

[Jokeyman123]

Depending upon the keyboard-most have 2 rubber collapsible boots, some have three-I think I recall the new Casio Privias all have three. Now we come to our physics lesson for the day-or geometry may be better-and it took me awhile to figure this one out. If you look carefully-you may notice that one boot is designed ever so slightly differently than the other-one is just a gerbil-hair taller than the other. Both are on/off contacts underneath to the circuit board but when you press the key-the 2 rubber boots must sense not only which one is contacting first and second, but it compares the rate at which the 2 rubber boots-the time between when the one contacts, then the other. This is what determines the dynamic response-the slower the time between (i am guessing here) the 2 boots contacting-the softer the sound-the faster /harder the response between the 2, the louder. The amazing thing to me is that this design works at all, since the measurements here are so tiny, and must be exactly right-the reason we can end up having so much trouble. If these boots are contaminated (inside) or damaged at all, there goes the key response. In my experience, the dynamic response can disappear but the key will still play-this means one or the other of the rubber boots has lost it's ability to bounce back away, and/or now both rubber boots are the same height and are sending an on/off signal at the same time. All this means-it can be a heckuva project to repair these if there is a problem-even when replacing the rubber strips with new ones-it has to be done very carefully, the rubber boots must be positioned exactly right and secure, with no dust or moose droppings in them! 

[craZivn]

Yep, the PX-5S has three contacts! In Picture #19 of the original post you can see the differing height of the contacts in the rubber strip if you look closely. The contacts on the circuit board, of course, are level. I think Jokeyman hit the nail on the head: The computer in the PX senses the minute time difference between contacts, and a shorter time equals a higher velocity of keystrike.

 

It is curious that there are three contacts. Does the third one add a sort of nuance to the keystrike by measuring the velocity curve at a third point, or is it for reliability in case the computer misses one of the contacts?

 

Ivan

[Jokeyman123]

I am pretty sure this design gives the PX series the extra control of dynamics with each keystroke-and I recall also allows for different triggering of the layers of piano samples to create the "AIR" acoustic resonance effect. amazing considering the miniscule rubber boot movements that must be detected, and instantly in order to duplicate an acoustic piano. Definitely sounds better to my ears than earlier designs. What changed me over to Casio-years ago while still teaching, I ordered 2 portable keys for the music room-we had an acoustic already and i had been using technology/computers. One was a Yamaha PSR I forget which, and the other was a Casio-one of the CTK's. This was a budget instrument, I didn't get much music dept. money for instruments-and it had the most realistic organ and piano sounds I'd heard-and I already had a Kurzweil digital piano, an Ensoniq TS-12 and several other pro workstations, Generalmusic, Yamaha SY77-this blew me away-I could not believe Casio could put such realistic sounds in what most would dismiss as a toy keyboard. I was a bit shaken, considering what my other instruments had cost-that's when I began to pay attention to Casio-and that was way back in the 1990s somewhere, years after my CZ's. Definitely made me pay attention. when I retired years later, that Casio was still working.