Upgrade your Yamaha DX7 II-D to Yamaha DX7 II-FD
February 2009 By CloudsWalker www.cloudswalker.com
Missing Parts on the Yamaha DX7 II-D :
IC5 Integrated Circuit 16 pin DIL : TC40H174P
6 x D-Flip-flop, can be replaced by 74HC174
IC6 Integrated Circuit 14 pin DIL : 7405 (TTL)
IC22 Integrated Circuit 28 Pin DIL : HM65256BLP12
SRAM, can be replaced by HM62256LP12 or equivalent
IC23 EPROM 27512 or 27C512 for the new Operating System
IC24 Integrated Circuit 28 Pin DIL : WD1772-PH (1986)
Western Digital Floppy Disk Controller
!!! 3,5 inch Floppy Disk with Drive Select 0 !!!
CN1 34 pin Floppy Disk Male Connector
34 pin flat cable between Main Board and Floppy Disk
Power cable between Power Supply Board and Floppy Disk
Parts collecting :
74HC174 is easy to found and found also one IC socket 16 pin DIL
7405 is easy to found and found also one IC socket 14 pin DIL
HM62256LP12 or equivalent is relatively easy to found and found also one IC socket 28 pin
EPROM 27C512 is relatively easy to found and found also one IC socket 28 pin DIL
WD1772 can by found on the Web … or removed from one Atari ST !!! + IC socket 28 pin
The floppy Disk can be 1.44Mb/720kb new … BUT with Drive Select 0
Battery replacement :
It will be judicious at this Time to change your Backup Battery ( 3V CR2032 )
It’s better to solder a socket. This socket can be removed from an old PC Mother Board
Procedure :