Repairing a Casio Piano Keyboard (CTK 400)

I find the finger movements of accomplished piano players to be poetic and mesmerizing. I don’t have delusions of ever reaching that mastery, but I do want to be able to play a few notes on a piano when accosted by one! So, a few years ago, I bought a cheap (but 61 key) electronic keyboard from Craigslist – a Casio CTK-400. And it sat in the closet till I was suddenly bestowed with oodles of time 2 months ago.

Learning to Play

So, I brought forth the keyboard from the darkness of my closet and embarked on a journey to learn to play Für Elise. I tried an ‘easy’ version for a week, but got disenchanted quickly because it sounded not nearly as pleasant as the true Für Elise. So, I downloaded the original score as a PDF document – and was flummoxed by the complexity of the notation! Mind you, I had no prior training in reading musical scores. That sent me on a detour to learn the basics of musical notation. It turned out to be much easier than I thought – I was able to read the score within an hour of starting out. Of course, I still read one staff at a time, and only by deduction, but at least I know what most of the symbols mean.

The initial few weeks of learning the piano was literally painful. Since the tendons and ligaments on your hands are not accustomed to the kind of reach you need for moving between keys, I couldn’t get more than 10 mins of playing in each session. But that has improved significantly in the 2-3 months I’ve been practicing, and now I can practice easily for one hour each session. I’m can now presentably play the first page of the Für Elise score after 2 months of regular practice.

Unfortunate Mishap

A few weeks ago, while practicing an especially intricate part of the score, I hit the B4 key, and it snapped! Most people would venture out to buy a new keyboard at this point, but pas moi! What’s the fun in buying a brand spanking new gadget when you can fix a broken one!!! My initial plan was to simply replace the broken key with one of the keys in a higher octave. So, I unscrewed the dozen odd screws of the bottom of my Casio CTK 400, took off the plastic enclosure on the top, and was immediately foiled.

You see, they keys on an electronic keyboard aren’t individual keys. They exist in banks of 4-5 connected keys built as a single plastic mould. And each set is shaped differently, so there are very few interchangeable sets. And the sets are layered, typically each octave consisting of 3 layers (2 layers for the white keys and 1 for the black).

That left me with only one option – somehow connect the broken key to the rest of the keys in the set. I could use superglue, but there would be sufficient strain at the join to break the key again at the very next stroke. So, I improvised.

The Repair

The solution I came up with was to brace the joint with a piece of metal. The metal strip would take up most of the strain when the key flexes, leaving the joint strain-free. I got my tin-snips out, located a can of tomato pureé in the recycle bag, and cut a piece of the can. I had to snip the top edge of the can using cutting pliers since the lip is too thick for the tin snips. Cutting the rest of the piece out was easy.

I then cut a thin strip out from the square piece – wide enough to sit inside the key cavity. I shaped the strip to follow the contour of the part where I was gluing. I first glued the 2 plastic parts where it had snapped using super glue. Then I put one drop of superglue on each end of the metal strip, and held it against the plastic surface for 10 seconds to get a firm bond. I had never noticed this before, but for a few seconds, the surface you are glueing heats up!

One thing you need to make sure is that both the metal and plastic surface are completely clean. I scrubbed the metal surface against the cutting edge of the snips and the plastic surface using some rubbing alcohol. The inner surface of cans have a plastic liner, so if you don’t scrape that liner off, you will only get a superficial bond and the metal will come right off since there is no glue on the metal surface itself.

I was then able to put the keys back together, and the piano was working again, save for a slightly harder stroke on the B4 key.

Update: The same key broke again after 2 weeks right beyond the end of the metal strip. I guess the plastic strip meant to provide the flexion is at the end of its life. Not to be defeated easily, I braced it again with a strip of metal on the other side.Let’s see how long this lasts. But the writing on the wall is clear – I need another keyboard if I intend to continue learning!

Acknowledgements: Thanks to FreeFoto.com for the Creative Commons licensed stock image of a keyboard.