Turns out the E! Card was not fully seated into the main board. In fact, the design of the E! Card precludes it being fully seated. The pins aren't long enough to be inserted completely into the ROM socket on the mainboard and this lifts the pins that go into the SRAM socket. I haven't come up with a clever solution for this yet. Additional symptoms of a loose E! Board are mainly refusal to boot with displays ranging from '88' on the LED display and a row of blocks across the LCD to random segments lighting on the LED display. Going Back To Stock I decided to revert back to the original stock setup, but this DX7 didn't come with its original pre-E! Fortunately, there are plenty of resources for DX7 repair on the Internet. Installing the E!Ĭard requires pulling IC14 and IC21. So, going back to stock means replacing them. IC14 - Firmware ROM IC14 turns out to have been a Toshiba TMM24128AP (16Kx8bit ROM). On ebay you can find folks selling a 'Special Edition' (SER-7) version of this ROM for the DX7. I also found that a.bin file of the original DX7 ROM (v1.8) is available in the YamahaDX Yahoo group's file collection. If you ask nicely, one of the ROM sellers on ebay will be more than happy to burn that.bin image to a ROM for you. I now have both the SER-7 special edition ROM and the original v1.8 DX7 ROM. IC21 - Static RAM IC21 is one of the three SRAM chips on the mainboard that comprise the internal memory. It is a Mitsubishi M5M5118P-15L (2Kx8bit SRAM). The DX7 can transfer patches back and forth via sysex.

See page 56 in the manual for instructions for configuring the DX7 to send/receive. (Function 8, set MIDI channel to 1, and SYSINFO to AVAIL. With the original chips in place, I've had no trouble at all with the DX7.

Occasionally, a bank from the Internet will crash it. Also, it has trouble handling certain MIDI messages. But then the DX7 MIDI implementation was always a bit weak as it predated the MIDI standard.

Dx7 patches fm8