Macintosh1/2 XL(Lisa 2/5) : Clobbers Other Nodes On ATalk
PROBLEM DESCRIPTION: A Macintosh 1/2 XL (originally called
Lisa 2/5) may suffer from noise problems on its receiving lines.
This interferes with its ability to hear other network devices,
so may think it is safe to broadcast even if another node is transmitting.
This can result in collisions that clobber other node's transmissions.
The problem only happens with units that have the old I/O PCBs (the
ones with battery packs).
CAUSE: The old I/O PCB needs to be upgraded.
CURE: 1. Cut R38 (location 12E above the battery pack).
2. Cut the trace leading to pin 3 of RP4 (location 12F)
If the above cure doesn't fix the problem, refer to the Lisa
Tech Procedures to obtain a troubleshooting procedure.