Category Archives: Yamaha DX7

Found Another DX7 Bug

This one isn’t a huge bug, but anyone with an original DX7 running OS version 1.7 or earlier (on an expander based on it) can see this bug.  If you edit a patch and set an oscillator mode for Fixed … Continue reading

Posted in Yamaha DX7 | 1 Comment

MIDI Velocity Tester

While looking into the DX7 and some of the expansions for it, I needed a way to capture all the possible velocities that a given MIDI keyboard could put out. Not all of them send all 127 possible velocities. I … Continue reading

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DX7 Velocity Issues

A lot of comments, cliche’s, criticisms and chit-chat exists about the original DX7 Velocity limitations.  I will address a few of those, mainly from the perspective of someone looking at the underlying code. It’s another level of fun for someone … Continue reading

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Yamaha DX7 OS without Active Sensing

While peeking around at the various DX7 firmware versions I was able to identify the code that is responsible for the DX7 transmitting $FE (MIDI Active Sensing) constantly.  I did not have the time to look at adding a menu … Continue reading

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Hitachi HD6303 Monitor

The Hitachi 6303 is a variation on the Motorola MC6800/6801/6803 Motorola microprocessors and microcontrollers from the late 70’s and early 80’s.  I have an interest in reverse engineering embedded systems from that era.  Previously I have created a 6809 EPROM … Continue reading

Posted in Hitachi HD6303, Yamaha DX7 | 6 Comments

A DX7 Expansion “for the rest of us”

The DX7 E! expansion is known for being very hard to use. The SuperMAX+ is easier, but still there are so many features that it can be hard to remember them all, … and not everyone needs them.  So I’m … Continue reading

Posted in Yamaha DX7 | Tagged , | 14 Comments

CR2032 Battery Holder PCB Saver Adapter (for DX7, etc)

Here is a quick “freebie” of sorts. I’ve had this PCB for a while and used them now and then to fix dead 3v coin cell batteries on Yamaha DX7’s and other synth’s and drum machines. You can order the … Continue reading

Posted in Uncategorized, Yamaha DX7 | Tagged , , , | 1 Comment

Yamaha DX7 ROM Cartridge BINs

I needed to get the BIN data from some DX7 cartridges, but I don’t have them all. I only have ROM3. So I desoldered the EPROM in the ROM 3 and compared that to the .SYX files found easily on … Continue reading

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Yamaha DX7 SuperMAX Redux

Something else I’m working on… The new circuit boards just arrived and the testing so far is good. The boards are a slight improvement over the original: I’ve increased the size to allow for a screw to hold the board … Continue reading

Posted in Yamaha DX7 | 13 Comments

Vintage Synth CPU Updates, Upgrades and Expansions

There are so many CPU upgrades now for our beloved synths of old, that I thought it would be nice to have a catalog of them all in one place. If someone else has done this already, please let me … Continue reading

Posted in Pro One CPU, Uncategorized, Yamaha DX7 | 4 Comments