APPLE //C & GS DISK ][ ADAPTER CABLES Parts needed: 1 IDP 20 plug (two for GS Dual Drive adapter) 1 DB 19 pin male connector 3' 20 conductor ribbon cable to build the adapter cables get an IDP-20 plug for //c adapter (Two for GS) one DB-19 male socket and three feet of 20 conductor ribbon cable for each drive and connect the connectors as shown. IDP-20 pins DB-19 pins 1 GND-------------------> 1 GND 2 PHASE 0---------------> 11 PHASE A 3 GND-------------------> 2 GND 4 PHASE 1---------------> 12 PHASE B 5 GND-------------------> 3 GND 6 PHASE 2---------------> 13 PHASE C 7 GND-------------------> 4 GND 8 PHASE 3---------------> 14 PHASE D 9 -12 V-----------------> 5 -12V 10 WRITE REQ-------------> 15 WRITE REQ 11 +5V-------------------> 6 +5V 12 +5V-------------------> 6 +5V 13 +12-------------------> 7 +12V 14 DRIVE ENABLE----------> 17 Drive one or 9 for drive 2 on GS 15 +12V------------------> 7 +12V 16 READ DATA-------------> 18 READ DATA 17 +12V------------------> 8 +12V 18 WRITE DATA------------> 19 WRITE DATA 19 +12V------------------> 8 +12V 20 WRITE PROTECT---------> 10 WRITE PROTECT 16 NOT CONNECTED One reliable source I've found for male DB19 connectors is JDR Micro Devices 800-538-5000 or 408-866-6200. I find it's easiest to connect the IDP connector to the ribbon cable first then soldering the various wires to the DB19. (Explains why I layed out the list the way I did doesn't it?). Once the cable is made connect the IDP connector to the twenty pin connector on your Disk ][ taking care that pin 1 of the plug connects to pin 1 of the drive connector. !!!!Failure to do this will destroy your motherboard!!!! These cables can be tricky and tedious to make. Be very careful and check all connections thoroughly. It's easy to mix them up. It is usually best to have someone else check the cable for the proper connections, since they will usually catch mistakes you might miss. To be safe ohm out the connections or use a continuity tester. !!!An incorrectly made cable can destroy your GS or //c motherboard!!! I can accept no responsibility for incorrectly made cables. Layout of IDP 20 1 3 5 7 9 11 13 15 17 _____________====_____________ | o o o o o o o o o o | | o o o o o o o o o o | |______________________________| 2 4 6 8 10 12 14 16 20 Pin one is usually marked with an arrow. Layout of DB19 1 2 3 4 5 6 7 8 9 10 _______________________________ \ . . . . . . . . . . / \ . . . . . . . . . / \ _________________________ / 11 12 13 14 15 16 17 18 19