If you have Larry Pina: Macintosh Repair and Upgrade Secrets First Ed 1990 he has a section on page 217 that your questions and comments encouraged me to read, when I realized it was not ADB! This may be old, but it is all new to me! What I learned tonight in brief was:
1. The correct cable is a straight through cable. Each pin is wired to its same number, position plug conductor at the other end.
2. If a telephone coiled handset cable is unfortunately substituted, the chip in the keyboard on a socket blows, and sometimes the chip at the inside the Mac128 blows too! Phone handset cables connect mirrored plug positions 1:4, 2:3, 3:2, 4:1 and are really bad news!.
3. The Mac128 intended keyboard is MO110, no suffix A. But the MO110 is mutually interchangeable with the MO110A. There is a replaceable 8021H or 8415 located near the caps lock key for the MO110, and a replaceable 8550 or 8728 on a socket under the spacebar in the MO110A model .
4. No info found on the Mac128K end of troubleshooting this.
So right off, it's important to make sure the cable is the right straight through kind, when the plugs are both held in parallel pointing towards you, leftmost position better connect to the other leftmost position, etc.
1. The correct cable is a straight through cable. Each pin is wired to its same number, position plug conductor at the other end.
2. If a telephone coiled handset cable is unfortunately substituted, the chip in the keyboard on a socket blows, and sometimes the chip at the inside the Mac128 blows too! Phone handset cables connect mirrored plug positions 1:4, 2:3, 3:2, 4:1 and are really bad news!.
3. The Mac128 intended keyboard is MO110, no suffix A. But the MO110 is mutually interchangeable with the MO110A. There is a replaceable 8021H or 8415 located near the caps lock key for the MO110, and a replaceable 8550 or 8728 on a socket under the spacebar in the MO110A model .
4. No info found on the Mac128K end of troubleshooting this.
So right off, it's important to make sure the cable is the right straight through kind, when the plugs are both held in parallel pointing towards you, leftmost position better connect to the other leftmost position, etc.