online website builder

DX9 Servicing 101

One of the realities of owning vintage electronic music equipment like a DX9 is that at some point, something is going to stop working.

However, there is some good news. Inside a DX9 there is a lot less to go wrong compared to an 80's analog polysynth. It's a digital synth with no complex signal paths, moving parts or voice cards to fail. For the most part, the DX9 mainboard consists of fairly standard 7400 series ICs and a handful of custom Yamaha chips - and that's it.  

The second piece of good news is that the most common issues with a DX9 are usually easy to fix. That is not to say that there aren't DX9s out there with serious problems. But, given how few DX9s there are and the fact that most of them have seen limited use, the odds are generally in our favour when trying to repair a DX9.

Note: These guides are provided as is and you undertake any of these repairs entirely at your own risk. These instructions come with no guarantees or warranties and I take no responsibility for any damage to equipment or injuries caused by following these guides.

Battery Failure & Replacement

The single most common fault with a DX9

The single most common fault you will find with a DX9 is a dead internal battery. The DX9 internal battery is a CR2032 permanently soldered on to the mainboard which has an approximate 10 year lifespan. Once it fails, it can be the root cause of several issues and it is generally not worth trying to diagnose any DX9 problems prior to replacing the battery and then loading in a set of factory patches.

To check the internal battery on a DX9, press the Function button and then hit button 19 until the battery voltage is displayed. If the displayed value is not between 2.2 and 3.3 volts, there is a problem with the battery. Readings of 4 volts or more have been the subject of emails to me and also debate on forums where individuals have suggested failed diodes and overcharged batteries which are liable to explode. In my experience, neither is more likely than the battery simply being dead.


The Story of the DX9

Where it came from and why it failed

Worst FM Synth Ever

Is it really that bad?

How it got that label and why we believe it

Patch Conversion

From the new to the old

Applications for generating DX9 patches

The Library

The fun stuff

Collection of original and converted DX9 patches

The 4Op Algorithms

There can be only 8

The how and the why of those algorithms

Data Tape 2

The Missing Patches

Why the initial DX9 data tape patches didn't match their descriptions

Patch Manager

Creating your own DX9 library

Application for managing and converting DX9 patches

Servicing 101

Getting your DX9 up and running

Fixing the most common issues with a DX9