Triplex group. Upon arrival F-3 fuse was opened on Number one car, replaced it and opened it right away. Checked out power supply seemed ok, replaced fuse again, and all seemed good, except for no hall calls work, turn off number one and the other two work fine. If we take either side communication cable off of J 2 of CPU on #1, the other cars answer hall calls, and #1 car works as if on independent. Leaning to CPU card, but looking for other inputs,from people that are smarter than me.