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

[anotherscott]

On 3/30/2020 at 2:00 PM, craZivn said:

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?

 

The middle sensor (which is what makes a board "tri-sensor" or "triple sensor") is an alteranate starting point which is used to allow the key to be restruck from a lower point in its travel. Also, it means that (without holding the sustain pedal down) you can restrike a note without silencing it first.  (Without the third sensor, in order to restrike a given note, you'd have to lift the key high enough to again be above the trigger point for the top sensor, which on the key's way up, also performs the function of silencing the note.) This better duplicates the behavior of a real grand piano.  People often say that the lower restrike point aids with quick reptitions, but it is more about the quiet repetitions. A loud repetition still requires lifting the key high, in order to achieve the velocity. Billy Joel's introduction to "Angry Young Man" has fast repetition, but a third sensor won't make a difference since the key comes up so high between each strike anyway. But a more gentle repetition will be easier to achieve if you don't have to lift the key as high between strikes, and you will be able to achieve it with more of a real piano technique. Trills are a common way this comes into play. That said, the middle sensor of the PX-5S triggers a bit on the high side, and is not as beneficial/authentic as on some other implementations.

[Solly]

On 6/1/2018 at 6:43 AM, craZivn said:

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

 

[Solly]

I've done the same for my Keyboard but the situation got worse. instead of not have only 3 dead notes the Whole keyboard doesn't have contact. and it was after I Cleaned under the the rubber dome contacts and replaced everything. there was some type of blackish grey substance there. please help. and its a light weighted keys.