[sdiy] Upgrading a DX7

[Brett Maddaford]

Robin Whittle used to do just this amongst other things, email him and
see if he still does.

Brett

-----Original Message-----
From: Scott Juskiw [mailto:scott at tellun.com] 
Sent: Wednesday, 7 September 2005 12:51 PM
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] Upgrading a DX7


Has anyone ever upgraded the ROM on a DX7? The TX816 manual mentions 
that some of the early DX7s have a bad MIDI implementation. Mine is 
one of those, I've wanted to upgrade it for years.

I found a pdf that discusses a DX7 "special edition" ROM with a 
number of enhancements (this is not as fancy as the e! upgrades). I 
found the DX7 schematics and in there it says that the ROM is:

IC14: HN613128P

Is there an EEPROM version of this chip? Does anybody have a hex dump 
of this "special edition" ROM, or even a proper version of the DX7 
ROM that sends the proper aftertouch over MIDI and doesn't send an 
endless stream of "F0 43" bytes? I have an EEPROM burner, I might be 
able to burn it myself if I had the chip and a ROM dump.

Thanks.