It would help to know a few things:

1. Are your servos analog controlled (+/-10v) slaved by the Galil, or are they digital (Step and Direction) with seperate inputs or do they share the same input?

2. Did this problem come with the retrofit or ran fine then appeared later?

Al's advice would pertain to the analog servos with Galil. The digital control can also be in the form of CW/CCW or A/B signals, S/D being the most common. The slaving can also be done with a master axis running either analog or digital and the slave running digital A/B encoder following off the master axis.