March 1, 2024

Repairing A Old Casio Casiotone MT-520 Keyboard

I found Casiotone keyboard in pretty bad shape at Goodwill. The keyboard bed was floating inside the case, two of the keys broke off. It was an interesting keyboard with the drum pads and since it still making sound, I wanted to give it a shot at repairing it.

My first step to getting this old keyboard in good condition again was to replace the keys. Unfortunately researching on the internet I couldn’t find any replacement keys for sale, other than buying an entire keyboard. I had no choice but to attempt a repair.

The Plastic key broke off. Here I’m placing where it should go to repair it.
Plastic molding repair keys
Using plastic molding I reattach the key back to the key bed

Unfortunately during the process of removing the keys for repairing them. The standoffs that hold the keys to the case broke. This needed to be repaired since the key bed will just float inside the case making it awkward to play. To repair, I simply superglue the standoffs and use plastic molding to ensure they stay on. Overall it doesn’t look the best, but you won’t see it anyways since it’s inside the keyboard.

Repaired standoffs

Capacitor Repair

There was one other issues I needed to address. One of the capacitors pop. While the keyboard was still functioning, I wanted to get this repaired before putting it back together. I use my solder pump which makes it much easier to remove through-hole opponents. I had to order the capacitors which took about a week to get.

While waiting for that, I found out one of the connectors for the external drum pad rusted away. I tried to find a replacement but I had no luck. So I decided to leave it, this wasn’t a critical part of the keyboard but it did annoy me. I don’t know what’s with Casiotone keyboards but finding parts for them ain’t easy, you would think it be easier for something mass-produced.

Putting Casiotone Back Together

After putting it all back together, It wouldn’t turn on. But I tried using batteries instead and it turned on fine. This is probably an issue with the power adapter. As I know it did power on in the store just fine with a power adapter. But I will come back to this later.

Two of the keys were not functioning very well and required pushing a bit harder for them to work. I think it was the heat gun, it caused the plastic to warp misaligning the keys.

For now, I decided to end the repair and come back to it later. I’m pretty happy with how The Casiotone MT-520 turned out. It’s a blast to play with Its old-sounding drums and cheesy-sounding loops. This Keyboard is great to annoy any family member within 20 feet, makes me feel like a kid again.


Computer guru with years working with technology. I find it fun to tinker with computer new and old, and make them do my work for me.

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