The alarm was on Y-axis. After staying powered on for about 10 minutes, with the machine not even running a Y-axis Excess error and tack generator alarm on a Fanuc O-M control would occur. The drive also showed these LED alarms on them though after testing several times, sometimes only one of the other LEDs would be on.
Checked all connections. Looked for maybe a heat problem. Left the cabinet doors open checked fans and connections.
CNC problem resolution
The X-axis drive and Y-axis drive were the same so I swapped the encoder feedback cables and motor leads. The problem stayed with the drive. I then swapped just the top board on the two drives and found that the problem went with the board. Ordered up a top board for about $3000 and replaced. Problems were gone.